Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * prepjointree.c
4 : : * Planner preprocessing for subqueries and join tree manipulation.
5 : : *
6 : : * NOTE: the intended sequence for invoking these operations is
7 : : * preprocess_relation_rtes
8 : : * replace_empty_jointree
9 : : * pull_up_sublinks
10 : : * preprocess_function_rtes
11 : : * pull_up_subqueries
12 : : * flatten_simple_union_all
13 : : * do expression preprocessing (including flattening JOIN alias vars)
14 : : * reduce_outer_joins
15 : : * remove_useless_result_rtes
16 : : *
17 : : *
18 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
19 : : * Portions Copyright (c) 1994, Regents of the University of California
20 : : *
21 : : *
22 : : * IDENTIFICATION
23 : : * src/backend/optimizer/prep/prepjointree.c
24 : : *
25 : : *-------------------------------------------------------------------------
26 : : */
27 : : #include "postgres.h"
28 : :
29 : : #include "access/table.h"
30 : : #include "catalog/pg_type.h"
31 : : #include "funcapi.h"
32 : : #include "miscadmin.h"
33 : : #include "nodes/makefuncs.h"
34 : : #include "nodes/multibitmapset.h"
35 : : #include "nodes/nodeFuncs.h"
36 : : #include "optimizer/clauses.h"
37 : : #include "optimizer/optimizer.h"
38 : : #include "optimizer/placeholder.h"
39 : : #include "optimizer/plancat.h"
40 : : #include "optimizer/prep.h"
41 : : #include "optimizer/subselect.h"
42 : : #include "optimizer/tlist.h"
43 : : #include "parser/parse_relation.h"
44 : : #include "parser/parsetree.h"
45 : : #include "rewrite/rewriteHandler.h"
46 : : #include "rewrite/rewriteManip.h"
47 : : #include "utils/rel.h"
48 : :
49 : :
50 : : typedef struct nullingrel_info
51 : : {
52 : : /*
53 : : * For each leaf RTE, nullingrels[rti] is the set of relids of outer joins
54 : : * that potentially null that RTE.
55 : : */
56 : : Relids *nullingrels;
57 : : /* Length of range table (maximum index in nullingrels[]) */
58 : : int rtlength; /* used only for assertion checks */
59 : : } nullingrel_info;
60 : :
61 : : /* Options for wrapping an expression for identification purposes */
62 : : typedef enum ReplaceWrapOption
63 : : {
64 : : REPLACE_WRAP_NONE, /* no expressions need to be wrapped */
65 : : REPLACE_WRAP_ALL, /* all expressions need to be wrapped */
66 : : REPLACE_WRAP_VARFREE, /* variable-free expressions need to be
67 : : * wrapped */
68 : : } ReplaceWrapOption;
69 : :
70 : : typedef struct pullup_replace_vars_context
71 : : {
72 : : PlannerInfo *root;
73 : : List *targetlist; /* tlist of subquery being pulled up */
74 : : RangeTblEntry *target_rte; /* RTE of subquery */
75 : : int result_relation; /* the index of the result relation in the
76 : : * rewritten query */
77 : : Relids relids; /* relids within subquery, as numbered after
78 : : * pullup (set only if target_rte->lateral) */
79 : : nullingrel_info *nullinfo; /* per-RTE nullingrel info (set only if
80 : : * target_rte->lateral) */
81 : : bool *outer_hasSubLinks; /* -> outer query's hasSubLinks */
82 : : int varno; /* varno of subquery */
83 : : ReplaceWrapOption wrap_option; /* do we need certain outputs to be PHVs? */
84 : : Node **rv_cache; /* cache for results with PHVs */
85 : : } pullup_replace_vars_context;
86 : :
87 : : typedef struct reduce_outer_joins_pass1_state
88 : : {
89 : : Relids relids; /* base relids within this subtree */
90 : : bool contains_outer; /* does subtree contain outer join(s)? */
91 : : Relids nullable_rels; /* base relids that are nullable within this
92 : : * subtree */
93 : : List *sub_states; /* List of states for subtree components */
94 : : } reduce_outer_joins_pass1_state;
95 : :
96 : : typedef struct reduce_outer_joins_pass2_state
97 : : {
98 : : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
99 : : List *partial_reduced; /* List of partially reduced FULL joins */
100 : : } reduce_outer_joins_pass2_state;
101 : :
102 : : typedef struct reduce_outer_joins_partial_state
103 : : {
104 : : int full_join_rti; /* RT index of a formerly-FULL join */
105 : : Relids unreduced_side; /* relids in its still-nullable side */
106 : : } reduce_outer_joins_partial_state;
107 : :
108 : : static Query *expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
109 : : RangeTblEntry *rte, int rt_index,
110 : : Relation relation);
111 : : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
112 : : Relids *relids);
113 : : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
114 : : Node **jtlink1, Relids available_rels1,
115 : : Node **jtlink2, Relids available_rels2);
116 : : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
117 : : JoinExpr *lowest_outer_join,
118 : : AppendRelInfo *containing_appendrel);
119 : : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
120 : : RangeTblEntry *rte,
121 : : JoinExpr *lowest_outer_join,
122 : : AppendRelInfo *containing_appendrel);
123 : : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
124 : : RangeTblEntry *rte);
125 : : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
126 : : int parentRTindex, Query *setOpQuery,
127 : : int childRToffset);
128 : : static void make_setop_translation_list(Query *query, int newvarno,
129 : : AppendRelInfo *appinfo);
130 : : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
131 : : RangeTblEntry *rte,
132 : : JoinExpr *lowest_outer_join);
133 : : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
134 : : RangeTblEntry *rte);
135 : : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
136 : : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
137 : : RangeTblEntry *rte,
138 : : AppendRelInfo *containing_appendrel);
139 : : static bool is_simple_union_all(Query *subquery);
140 : : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
141 : : List *colTypes);
142 : : static bool is_safe_append_member(Query *subquery);
143 : : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
144 : : Node *jtnode, bool restricted,
145 : : Relids safe_upper_varnos);
146 : : static void perform_pullup_replace_vars(PlannerInfo *root,
147 : : pullup_replace_vars_context *rvcontext,
148 : : AppendRelInfo *containing_appendrel);
149 : : static void replace_vars_in_jointree(Node *jtnode,
150 : : pullup_replace_vars_context *context);
151 : : static Node *pullup_replace_vars(Node *expr,
152 : : pullup_replace_vars_context *context);
153 : : static Node *pullup_replace_vars_callback(const Var *var,
154 : : replace_rte_variables_context *context);
155 : : static Query *pullup_replace_vars_subquery(Query *query,
156 : : pullup_replace_vars_context *context);
157 : : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
158 : : static void reduce_outer_joins_pass2(Node *jtnode,
159 : : reduce_outer_joins_pass1_state *state1,
160 : : reduce_outer_joins_pass2_state *state2,
161 : : PlannerInfo *root,
162 : : Relids nonnullable_rels,
163 : : List *forced_null_vars);
164 : : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
165 : : int rtindex, Relids relids);
166 : : static bool has_notnull_forced_var(PlannerInfo *root, List *forced_null_vars,
167 : : reduce_outer_joins_pass1_state *right_state);
168 : : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
169 : : Node **parent_quals,
170 : : Relids *dropped_outer_joins);
171 : : static int get_result_relid(PlannerInfo *root, Node *jtnode);
172 : : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
173 : : static bool find_dependent_phvs(PlannerInfo *root, int varno);
174 : : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
175 : : Node *node, int varno);
176 : : static void substitute_phv_relids(Node *node,
177 : : int varno, Relids subrelids);
178 : : static void fix_append_rel_relids(PlannerInfo *root, int varno,
179 : : Relids subrelids);
180 : : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
181 : : static nullingrel_info *get_nullingrels(Query *parse);
182 : : static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
183 : : nullingrel_info *info);
184 : :
185 : :
186 : : /*
187 : : * transform_MERGE_to_join
188 : : * Replace a MERGE's jointree to also include the target relation.
189 : : */
190 : : void
1499 alvherre@alvh.no-ip. 191 :CBC 399136 : transform_MERGE_to_join(Query *parse)
192 : : {
193 : : RangeTblEntry *joinrte;
194 : : JoinExpr *joinexpr;
195 : : bool have_action[NUM_MERGE_MATCH_KINDS];
196 : : JoinType jointype;
197 : : int joinrti;
198 : : List *vars;
199 : : RangeTblRef *rtr;
200 : : FromExpr *target;
201 : : Node *source;
202 : : int sourcerti;
203 : :
204 [ + + ]: 399136 : if (parse->commandType != CMD_MERGE)
205 : 397576 : return;
206 : :
207 : : /* XXX probably bogus */
208 : 1560 : vars = NIL;
209 : :
210 : : /*
211 : : * Work out what kind of join is required. If there any WHEN NOT MATCHED
212 : : * BY SOURCE/TARGET actions, an outer join is required so that we process
213 : : * all unmatched tuples from the source and/or target relations.
214 : : * Otherwise, we can use an inner join.
215 : : */
766 dean.a.rasheed@gmail 216 : 1560 : have_action[MERGE_WHEN_MATCHED] = false;
217 : 1560 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
218 : 1560 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
219 : :
220 [ + - + + : 5466 : foreach_node(MergeAction, action, parse->mergeActionList)
+ + ]
221 : : {
222 [ + + ]: 2346 : if (action->commandType != CMD_NOTHING)
223 : 2278 : have_action[action->matchKind] = true;
224 : : }
225 : :
226 [ + + ]: 1560 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
227 [ + + ]: 105 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
228 : 80 : jointype = JOIN_FULL;
229 [ + + ]: 1480 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
230 : 25 : jointype = JOIN_LEFT;
231 [ + + ]: 1455 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
1499 alvherre@alvh.no-ip. 232 : 674 : jointype = JOIN_RIGHT;
233 : : else
234 : 781 : jointype = JOIN_INNER;
235 : :
236 : : /* Manufacture a join RTE to use. */
237 : 1560 : joinrte = makeNode(RangeTblEntry);
238 : 1560 : joinrte->rtekind = RTE_JOIN;
239 : 1560 : joinrte->jointype = jointype;
240 : 1560 : joinrte->joinmergedcols = 0;
241 : 1560 : joinrte->joinaliasvars = vars;
242 : 1560 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
243 : 1560 : joinrte->joinrightcols = NIL; /* ditto */
244 : 1560 : joinrte->join_using_alias = NULL;
245 : :
246 : 1560 : joinrte->alias = NULL;
247 : 1560 : joinrte->eref = makeAlias("*MERGE*", NIL);
248 : 1560 : joinrte->lateral = false;
249 : 1560 : joinrte->inh = false;
250 : 1560 : joinrte->inFromCl = true;
251 : :
252 : : /*
253 : : * Add completed RTE to pstate's range table list, so that we know its
254 : : * index.
255 : : */
256 : 1560 : parse->rtable = lappend(parse->rtable, joinrte);
257 : 1560 : joinrti = list_length(parse->rtable);
258 : :
259 : : /*
260 : : * Create a JOIN between the target and the source relation.
261 : : *
262 : : * Here the target is identified by parse->mergeTargetRelation. For a
263 : : * regular table, this will equal parse->resultRelation, but for a
264 : : * trigger-updatable view, it will be the expanded view subquery that we
265 : : * need to pull data from.
266 : : *
267 : : * The source relation is in parse->jointree->fromlist, but any quals in
268 : : * parse->jointree->quals are restrictions on the target relation (if the
269 : : * target relation is an auto-updatable view).
270 : : */
271 : : /* target rel, with any quals */
766 dean.a.rasheed@gmail 272 : 1560 : rtr = makeNode(RangeTblRef);
273 : 1560 : rtr->rtindex = parse->mergeTargetRelation;
579 274 : 1560 : target = makeFromExpr(list_make1(rtr), parse->jointree->quals);
275 : :
276 : : /* source rel (expect exactly one -- see transformMergeStmt()) */
277 [ - + ]: 1560 : Assert(list_length(parse->jointree->fromlist) == 1);
278 : 1560 : source = linitial(parse->jointree->fromlist);
279 : :
280 : : /*
281 : : * index of source rel (expect either a RangeTblRef or a JoinExpr -- see
282 : : * transformFromClauseItem()).
283 : : */
284 [ + + ]: 1560 : if (IsA(source, RangeTblRef))
285 : 1490 : sourcerti = ((RangeTblRef *) source)->rtindex;
286 [ + - ]: 70 : else if (IsA(source, JoinExpr))
287 : 70 : sourcerti = ((JoinExpr *) source)->rtindex;
288 : : else
289 : : {
579 dean.a.rasheed@gmail 290 [ # # ]:UBC 0 : elog(ERROR, "unrecognized source node type: %d",
291 : : (int) nodeTag(source));
292 : : sourcerti = 0; /* keep compiler quiet */
293 : : }
294 : :
295 : : /* Join the source and target */
1499 alvherre@alvh.no-ip. 296 :CBC 1560 : joinexpr = makeNode(JoinExpr);
297 : 1560 : joinexpr->jointype = jointype;
298 : 1560 : joinexpr->isNatural = false;
579 dean.a.rasheed@gmail 299 : 1560 : joinexpr->larg = (Node *) target;
300 : 1560 : joinexpr->rarg = source;
1499 alvherre@alvh.no-ip. 301 : 1560 : joinexpr->usingClause = NIL;
302 : 1560 : joinexpr->join_using_alias = NULL;
766 dean.a.rasheed@gmail 303 : 1560 : joinexpr->quals = parse->mergeJoinCondition;
1499 alvherre@alvh.no-ip. 304 : 1560 : joinexpr->alias = NULL;
305 : 1560 : joinexpr->rtindex = joinrti;
306 : :
307 : : /* Make the new join be the sole entry in the query's jointree */
308 : 1560 : parse->jointree->fromlist = list_make1(joinexpr);
309 : 1560 : parse->jointree->quals = NULL;
310 : :
311 : : /*
312 : : * If necessary, mark parse->targetlist entries that refer to the target
313 : : * as nullable by the join. Normally the targetlist will be empty for a
314 : : * MERGE, but if the target is a trigger-updatable view, it will contain a
315 : : * whole-row Var referring to the expanded view query.
316 : : */
796 dean.a.rasheed@gmail 317 [ + + + + ]: 1560 : if (parse->targetList != NIL &&
318 [ + + ]: 35 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
319 : 35 : parse->targetList = (List *)
320 : 35 : add_nulling_relids((Node *) parse->targetList,
321 : 35 : bms_make_singleton(parse->mergeTargetRelation),
322 : 35 : bms_make_singleton(joinrti));
323 : :
324 : : /*
325 : : * If the source relation is on the outer side of the join, mark any
326 : : * source relation Vars in the join condition, actions, and RETURNING list
327 : : * as nullable by the join. These Vars will be added to the targetlist by
328 : : * preprocess_targetlist(), so it's important to mark them correctly here.
329 : : *
330 : : * It might seem that this is not necessary for Vars in the join
331 : : * condition, since it is inside the join, but it is also needed above the
332 : : * join (in the ModifyTable node) to distinguish between the MATCHED and
333 : : * NOT MATCHED BY SOURCE cases -- see ExecMergeMatched(). Note that this
334 : : * creates a modified copy of the join condition, for use above the join,
335 : : * without modifying the original join condition, inside the join.
336 : : */
579 337 [ + + + + ]: 1560 : if (jointype == JOIN_LEFT || jointype == JOIN_FULL)
338 : : {
339 : 105 : parse->mergeJoinCondition =
340 : 105 : add_nulling_relids(parse->mergeJoinCondition,
341 : 105 : bms_make_singleton(sourcerti),
342 : 105 : bms_make_singleton(joinrti));
343 : :
344 [ + - + + : 500 : foreach_node(MergeAction, action, parse->mergeActionList)
+ + ]
345 : : {
346 : 290 : action->qual =
347 : 290 : add_nulling_relids(action->qual,
348 : 290 : bms_make_singleton(sourcerti),
349 : 290 : bms_make_singleton(joinrti));
350 : :
351 : 290 : action->targetList = (List *)
352 : 290 : add_nulling_relids((Node *) action->targetList,
353 : 290 : bms_make_singleton(sourcerti),
354 : 290 : bms_make_singleton(joinrti));
355 : : }
356 : :
357 : 105 : parse->returningList = (List *)
358 : 105 : add_nulling_relids((Node *) parse->returningList,
359 : 105 : bms_make_singleton(sourcerti),
360 : 105 : bms_make_singleton(joinrti));
361 : : }
362 : :
363 : : /*
364 : : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
365 : : * use the join condition to distinguish between MATCHED and NOT MATCHED
366 : : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
367 : : * NULL, saving cycles during planning and execution.
368 : : *
369 : : * We need to be careful though: the executor evaluates this condition
370 : : * using the output of the join subplan node, which nulls the output from
371 : : * the source relation when the join condition doesn't match. That risks
372 : : * producing incorrect results when rechecking using a "non-strict" join
373 : : * condition, such as "src.col IS NOT DISTINCT FROM tgt.col". To guard
374 : : * against that, we add an additional "src IS NOT NULL" check to the join
375 : : * condition, so that it does the right thing when performing a recheck
376 : : * based on the output of the join subplan.
377 : : */
378 [ + + ]: 1560 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
379 : : {
380 : : Var *var;
381 : : NullTest *ntest;
382 : :
383 : : /* source wholerow Var (nullable by the new join) */
384 : 105 : var = makeWholeRowVar(rt_fetch(sourcerti, parse->rtable),
385 : : sourcerti, 0, false);
386 : 105 : var->varnullingrels = bms_make_singleton(joinrti);
387 : :
388 : : /* "src IS NOT NULL" check */
389 : 105 : ntest = makeNode(NullTest);
390 : 105 : ntest->arg = (Expr *) var;
391 : 105 : ntest->nulltesttype = IS_NOT_NULL;
392 : 105 : ntest->argisrow = false;
393 : 105 : ntest->location = -1;
394 : :
395 : : /* combine it with the original join condition */
396 : 105 : parse->mergeJoinCondition =
397 : 105 : (Node *) make_and_qual((Node *) ntest, parse->mergeJoinCondition);
398 : : }
399 : : else
400 : 1455 : parse->mergeJoinCondition = NULL; /* join condition not needed */
401 : : }
402 : :
403 : : /*
404 : : * preprocess_relation_rtes
405 : : * Do the preprocessing work for any relation RTEs in the FROM clause.
406 : : *
407 : : * This scans the rangetable for relation RTEs and retrieves the necessary
408 : : * catalog information for each relation. Using this information, it clears
409 : : * the inh flag for any relation that has no children, collects not-null
410 : : * attribute numbers for any relation that has column not-null constraints, and
411 : : * expands virtual generated columns for any relation that contains them.
412 : : *
413 : : * Note that expanding virtual generated columns may cause the query tree to
414 : : * have new copies of rangetable entries. Therefore, we have to use list_nth
415 : : * instead of foreach when iterating over the query's rangetable.
416 : : *
417 : : * Returns a modified copy of the query tree, if any relations with virtual
418 : : * generated columns are present.
419 : : */
420 : : Query *
287 rguo@postgresql.org 421 :GNC 434052 : preprocess_relation_rtes(PlannerInfo *root)
422 : : {
423 : 434052 : Query *parse = root->parse;
424 : : int rtable_size;
425 : : int rt_index;
426 : :
427 : 434052 : rtable_size = list_length(parse->rtable);
428 : :
429 [ + + ]: 981707 : for (rt_index = 0; rt_index < rtable_size; rt_index++)
430 : : {
431 : 547655 : RangeTblEntry *rte = rt_fetch(rt_index + 1, parse->rtable);
432 : : Relation relation;
433 : :
434 : : /* We only care about relation RTEs. */
435 [ + + ]: 547655 : if (rte->rtekind != RTE_RELATION)
436 : 179784 : continue;
437 : :
438 : : /*
439 : : * We need not lock the relation since it was already locked by the
440 : : * rewriter.
441 : : */
442 : 367871 : relation = table_open(rte->relid, NoLock);
443 : :
444 : : /*
445 : : * Check to see if the relation actually has any children; if not,
446 : : * clear the inh flag so we can treat it as a plain base relation.
447 : : *
448 : : * Note: this could give a false-positive result, if the rel once had
449 : : * children but no longer does. We used to be able to clear rte->inh
450 : : * later on when we discovered that, but no more; we have to handle
451 : : * such cases as full-fledged inheritance.
452 : : */
453 [ + + ]: 367871 : if (rte->inh)
454 : 312817 : rte->inh = relation->rd_rel->relhassubclass;
455 : :
456 : : /*
457 : : * Check to see if the relation has any column not-null constraints;
458 : : * if so, retrieve the constraint information and store it in a
459 : : * relation OID based hash table.
460 : : */
461 : 367871 : get_relation_notnullatts(root, relation);
462 : :
463 : : /*
464 : : * Check to see if the relation has any virtual generated columns; if
465 : : * so, replace all Var nodes in the query that reference these columns
466 : : * with the generation expressions.
467 : : */
468 : 367871 : parse = expand_virtual_generated_columns(root, parse,
469 : : rte, rt_index + 1,
470 : : relation);
471 : :
472 : 367871 : table_close(relation, NoLock);
473 : : }
474 : :
475 : 434052 : return parse;
476 : : }
477 : :
478 : : /*
479 : : * expand_virtual_generated_columns
480 : : * Expand virtual generated columns for the given relation.
481 : : *
482 : : * This checks whether the given relation has any virtual generated columns,
483 : : * and if so, replaces all Var nodes in the query that reference those columns
484 : : * with their generation expressions.
485 : : *
486 : : * Returns a modified copy of the query tree if the relation contains virtual
487 : : * generated columns.
488 : : */
489 : : static Query *
490 : 367871 : expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
491 : : RangeTblEntry *rte, int rt_index,
492 : : Relation relation)
493 : : {
494 : : TupleDesc tupdesc;
495 : :
496 : : /* Only normal relations can have virtual generated columns */
497 [ - + ]: 367871 : Assert(rte->rtekind == RTE_RELATION);
498 : :
499 : 367871 : tupdesc = RelationGetDescr(relation);
500 [ + + + + ]: 367871 : if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
501 : : {
502 : 1100 : List *tlist = NIL;
503 : : pullup_replace_vars_context rvcontext;
13 dean.a.rasheed@gmail 504 : 1100 : List *save_exclRelTlist = NIL;
505 : :
287 rguo@postgresql.org 506 [ + + ]: 4346 : for (int i = 0; i < tupdesc->natts; i++)
507 : : {
508 : 3246 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
509 : : TargetEntry *tle;
510 : :
511 [ + + ]: 3246 : if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
512 : : {
513 : : Node *defexpr;
514 : :
515 : 1475 : defexpr = build_generation_expression(relation, i + 1);
516 : 1475 : ChangeVarNodes(defexpr, 1, rt_index, 0);
517 : :
518 : 1475 : tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
519 : 1475 : tlist = lappend(tlist, tle);
520 : : }
521 : : else
522 : : {
523 : : Var *var;
524 : :
525 : 1771 : var = makeVar(rt_index,
526 : 1771 : i + 1,
527 : : attr->atttypid,
528 : : attr->atttypmod,
529 : : attr->attcollation,
530 : : 0);
531 : :
532 : 1771 : tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
533 : 1771 : tlist = lappend(tlist, tle);
534 : : }
535 : : }
536 : :
537 [ - + ]: 1100 : Assert(list_length(tlist) > 0);
538 [ - + ]: 1100 : Assert(!rte->lateral);
539 : :
540 : : /*
541 : : * The relation's targetlist items are now in the appropriate form to
542 : : * insert into the query, except that we may need to wrap them in
543 : : * PlaceHolderVars. Set up required context data for
544 : : * pullup_replace_vars.
545 : : */
546 : 1100 : rvcontext.root = root;
547 : 1100 : rvcontext.targetlist = tlist;
548 : 1100 : rvcontext.target_rte = rte;
549 : 1100 : rvcontext.result_relation = parse->resultRelation;
550 : : /* won't need these values */
551 : 1100 : rvcontext.relids = NULL;
552 : 1100 : rvcontext.nullinfo = NULL;
553 : : /* pass NULL for outer_hasSubLinks */
554 : 1100 : rvcontext.outer_hasSubLinks = NULL;
555 : 1100 : rvcontext.varno = rt_index;
556 : : /* this flag will be set below, if needed */
557 : 1100 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
558 : : /* initialize cache array with indexes 0 .. length(tlist) */
559 : 1100 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
560 : : sizeof(Node *));
561 : :
562 : : /*
563 : : * If the query uses grouping sets, we need a PlaceHolderVar for each
564 : : * expression of the relation's targetlist items. (See comments in
565 : : * pull_up_simple_subquery().)
566 : : */
567 [ + + ]: 1100 : if (parse->groupingSets)
568 : 10 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
569 : :
570 : : /*
571 : : * Apply pullup variable replacement throughout the query tree.
572 : : *
573 : : * We intentionally do not touch the EXCLUDED pseudo-relation's
574 : : * targetlist here. Various places in the planner assume that it
575 : : * contains only Vars, and we want that to remain the case. More
576 : : * importantly, we don't want setrefs.c to turn any expanded
577 : : * EXCLUDED.virtual_column expressions in other parts of the query
578 : : * back into Vars referencing the original virtual column, which
579 : : * set_plan_refs() would do if exclRelTlist contained matching
580 : : * expressions.
581 : : */
13 dean.a.rasheed@gmail 582 [ + + ]: 1100 : if (parse->onConflict)
583 : : {
584 : 50 : save_exclRelTlist = parse->onConflict->exclRelTlist;
585 : 50 : parse->onConflict->exclRelTlist = NIL;
586 : : }
587 : :
287 rguo@postgresql.org 588 : 1100 : parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
589 : :
13 dean.a.rasheed@gmail 590 [ + + ]: 1100 : if (parse->onConflict)
591 : 50 : parse->onConflict->exclRelTlist = save_exclRelTlist;
592 : : }
593 : :
287 rguo@postgresql.org 594 : 367871 : return parse;
595 : : }
596 : :
597 : : /*
598 : : * replace_empty_jointree
599 : : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
600 : : * relation.
601 : : *
602 : : * By doing this, we can avoid a bunch of corner cases that formerly existed
603 : : * for SELECTs with omitted FROM clauses. An example is that a subquery
604 : : * with empty jointree previously could not be pulled up, because that would
605 : : * have resulted in an empty relid set, making the subquery not uniquely
606 : : * identifiable for join or PlaceHolderVar processing.
607 : : *
608 : : * Unlike most other functions in this file, this function doesn't recurse;
609 : : * we rely on other processing to invoke it on sub-queries at suitable times.
610 : : */
611 : : void
2654 tgl@sss.pgh.pa.us 612 :CBC 434052 : replace_empty_jointree(Query *parse)
613 : : {
614 : : RangeTblEntry *rte;
615 : : Index rti;
616 : : RangeTblRef *rtr;
617 : :
618 : : /* Nothing to do if jointree is already nonempty */
619 [ + + ]: 434052 : if (parse->jointree->fromlist != NIL)
620 : 288302 : return;
621 : :
622 : : /* We mustn't change it in the top level of a setop tree, either */
623 [ + + ]: 145750 : if (parse->setOperations)
624 : 5520 : return;
625 : :
626 : : /* Create suitable RTE */
627 : 140230 : rte = makeNode(RangeTblEntry);
628 : 140230 : rte->rtekind = RTE_RESULT;
629 : 140230 : rte->eref = makeAlias("*RESULT*", NIL);
630 : :
631 : : /* Add it to rangetable */
632 : 140230 : parse->rtable = lappend(parse->rtable, rte);
633 : 140230 : rti = list_length(parse->rtable);
634 : :
635 : : /* And jam a reference into the jointree */
636 : 140230 : rtr = makeNode(RangeTblRef);
637 : 140230 : rtr->rtindex = rti;
638 : 140230 : parse->jointree->fromlist = list_make1(rtr);
639 : : }
640 : :
641 : : /*
642 : : * pull_up_sublinks
643 : : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
644 : : * semijoins or anti-semijoins.
645 : : *
646 : : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
647 : : * sub-SELECT up to become a rangetable entry and treating the implied
648 : : * comparisons as quals of a semijoin. However, this optimization *only*
649 : : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
650 : : * distinguish whether the ANY ought to return FALSE or NULL in cases
651 : : * involving NULL inputs. Also, in an outer join's ON clause we can only
652 : : * do this if the sublink is degenerate (ie, references only the nullable
653 : : * side of the join). In that case it is legal to push the semijoin
654 : : * down into the nullable side of the join. If the sublink references any
655 : : * nonnullable-side variables then it would have to be evaluated as part
656 : : * of the outer join, which makes things way too complicated.
657 : : *
658 : : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
659 : : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
660 : : *
661 : : * This routine searches for such clauses and does the necessary parsetree
662 : : * transformations if any are found.
663 : : *
664 : : * This routine has to run before preprocess_expression(), so the quals
665 : : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
666 : : * to be AND/OR-flat either. That means we need to recursively search through
667 : : * explicit AND clauses. We stop as soon as we hit a non-AND item.
668 : : */
669 : : void
6470 670 : 33189 : pull_up_sublinks(PlannerInfo *root)
671 : : {
672 : : Node *jtnode;
673 : : Relids relids;
674 : :
675 : : /* Begin recursion through the jointree */
6278 676 : 33189 : jtnode = pull_up_sublinks_jointree_recurse(root,
677 : 33189 : (Node *) root->parse->jointree,
678 : : &relids);
679 : :
680 : : /*
681 : : * root->parse->jointree must always be a FromExpr, so insert a dummy one
682 : : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
683 : : */
684 [ + + ]: 33189 : if (IsA(jtnode, FromExpr))
685 : 24292 : root->parse->jointree = (FromExpr *) jtnode;
686 : : else
687 : 8897 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
6470 688 : 33189 : }
689 : :
690 : : /*
691 : : * Recurse through jointree nodes for pull_up_sublinks()
692 : : *
693 : : * In addition to returning the possibly-modified jointree node, we return
694 : : * a relids set of the contained rels into *relids.
695 : : */
696 : : static Node *
697 : 111751 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
698 : : Relids *relids)
699 : : {
700 : : /* Since this function recurses, it could be driven to stack overflow. */
1230 701 : 111751 : check_stack_depth();
702 : :
6470 703 [ - + ]: 111751 : if (jtnode == NULL)
704 : : {
6470 tgl@sss.pgh.pa.us 705 :UBC 0 : *relids = NULL;
706 : : }
6470 tgl@sss.pgh.pa.us 707 [ + + ]:CBC 111751 : else if (IsA(jtnode, RangeTblRef))
708 : : {
709 : 61679 : int varno = ((RangeTblRef *) jtnode)->rtindex;
710 : :
711 : 61679 : *relids = bms_make_singleton(varno);
712 : : /* jtnode is returned unmodified */
713 : : }
714 [ + + ]: 50072 : else if (IsA(jtnode, FromExpr))
715 : : {
716 : 33380 : FromExpr *f = (FromExpr *) jtnode;
717 : 33380 : List *newfromlist = NIL;
718 : 33380 : Relids frelids = NULL;
719 : : FromExpr *newf;
720 : : Node *jtlink;
721 : : ListCell *l;
722 : :
723 : : /* First, recurse to process children and collect their relids */
724 [ + - + + : 69516 : foreach(l, f->fromlist)
+ + ]
725 : : {
726 : : Node *newchild;
727 : : Relids childrelids;
728 : :
729 : 36136 : newchild = pull_up_sublinks_jointree_recurse(root,
730 : 36136 : lfirst(l),
731 : : &childrelids);
732 : 36136 : newfromlist = lappend(newfromlist, newchild);
733 : 36136 : frelids = bms_join(frelids, childrelids);
734 : : }
735 : : /* Build the replacement FromExpr; no quals yet */
6278 736 : 33380 : newf = makeFromExpr(newfromlist, NULL);
737 : : /* Set up a link representing the rebuilt jointree */
738 : 33380 : jtlink = (Node *) newf;
739 : : /* Now process qual --- all children are available for use */
5212 740 : 33380 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
741 : : &jtlink, frelids,
742 : : NULL, NULL);
743 : :
744 : : /*
745 : : * Note that the result will be either newf, or a stack of JoinExprs
746 : : * with newf at the base. We rely on subsequent optimization steps to
747 : : * flatten this and rearrange the joins as needed.
748 : : *
749 : : * Although we could include the pulled-up subqueries in the returned
750 : : * relids, there's no need since upper quals couldn't refer to their
751 : : * outputs anyway.
752 : : */
6470 753 : 33380 : *relids = frelids;
6278 754 : 33380 : jtnode = jtlink;
755 : : }
6470 756 [ + - ]: 16692 : else if (IsA(jtnode, JoinExpr))
757 : : {
758 : : JoinExpr *j;
759 : : Relids leftrelids;
760 : : Relids rightrelids;
761 : : Node *jtlink;
762 : :
763 : : /*
764 : : * Make a modifiable copy of join node, but don't bother copying its
765 : : * subnodes (yet).
766 : : */
146 michael@paquier.xyz 767 :GNC 16692 : j = palloc_object(JoinExpr);
6470 tgl@sss.pgh.pa.us 768 :CBC 16692 : memcpy(j, jtnode, sizeof(JoinExpr));
6278 769 : 16692 : jtlink = (Node *) j;
770 : :
771 : : /* Recurse to process children and collect their relids */
6470 772 : 16692 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
773 : : &leftrelids);
774 : 16692 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
775 : : &rightrelids);
776 : :
777 : : /*
778 : : * Now process qual, showing appropriate child relids as available,
779 : : * and attach any pulled-up jointree items at the right place. In the
780 : : * inner-join case we put new JoinExprs above the existing one (much
781 : : * as for a FromExpr-style join). In outer-join cases the new
782 : : * JoinExprs must go into the nullable side of the outer join. The
783 : : * point of the available_rels machinations is to ensure that we only
784 : : * pull up quals for which that's okay.
785 : : *
786 : : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI,
787 : : * JOIN_RIGHT_SEMI, or JOIN_RIGHT_ANTI jointypes here.
788 : : */
789 [ + + + + : 16692 : switch (j->jointype)
- ]
790 : : {
791 : 7775 : case JOIN_INNER:
792 : 7775 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
793 : : &jtlink,
794 : : bms_union(leftrelids,
795 : : rightrelids),
796 : : NULL, NULL);
797 : 7775 : break;
798 : 8817 : case JOIN_LEFT:
799 : 8817 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
800 : : &j->rarg,
801 : : rightrelids,
802 : : NULL, NULL);
803 : 8817 : break;
804 : 20 : case JOIN_FULL:
805 : : /* can't do anything with full-join quals */
806 : 20 : break;
807 : 80 : case JOIN_RIGHT:
808 : 80 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
809 : : &j->larg,
810 : : leftrelids,
811 : : NULL, NULL);
812 : 80 : break;
6470 tgl@sss.pgh.pa.us 813 :UBC 0 : default:
814 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
815 : : (int) j->jointype);
816 : : break;
817 : : }
818 : :
819 : : /*
820 : : * Although we could include the pulled-up subqueries in the returned
821 : : * relids, there's no need since upper quals couldn't refer to their
822 : : * outputs anyway. But we *do* need to include the join's own rtindex
823 : : * because we haven't yet collapsed join alias variables, so upper
824 : : * levels would mistakenly think they couldn't use references to this
825 : : * join.
826 : : */
6278 tgl@sss.pgh.pa.us 827 :CBC 16692 : *relids = bms_join(leftrelids, rightrelids);
828 [ + - ]: 16692 : if (j->rtindex)
829 : 16692 : *relids = bms_add_member(*relids, j->rtindex);
830 : 16692 : jtnode = jtlink;
831 : : }
832 : : else
6470 tgl@sss.pgh.pa.us 833 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
834 : : (int) nodeTag(jtnode));
6470 tgl@sss.pgh.pa.us 835 :CBC 111751 : return jtnode;
836 : : }
837 : :
838 : : /*
839 : : * Recurse through top-level qual nodes for pull_up_sublinks()
840 : : *
841 : : * jtlink1 points to the link in the jointree where any new JoinExprs should
842 : : * be inserted if they reference available_rels1 (i.e., available_rels1
843 : : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
844 : : * point to a second link where new JoinExprs should be inserted if they
845 : : * reference available_rels2 (pass NULL for both those arguments if not used).
846 : : * Note that SubLinks referencing both sets of variables cannot be optimized.
847 : : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
848 : : * and/or jtlink2 in the order we encounter them. We rely on subsequent
849 : : * optimization to rearrange the stack if appropriate.
850 : : *
851 : : * Returns the replacement qual node, or NULL if the qual should be removed.
852 : : */
853 : : static Node *
854 : 122270 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
855 : : Node **jtlink1, Relids available_rels1,
856 : : Node **jtlink2, Relids available_rels2)
857 : : {
8506 858 [ + + ]: 122270 : if (node == NULL)
859 : 5300 : return NULL;
860 [ + + ]: 116970 : if (IsA(node, SubLink))
861 : : {
8310 bruce@momjian.us 862 : 4475 : SubLink *sublink = (SubLink *) node;
863 : : JoinExpr *j;
864 : : Relids child_rels;
865 : :
866 : : /* Is it a convertible ANY or EXISTS clause? */
6473 tgl@sss.pgh.pa.us 867 [ + + ]: 4475 : if (sublink->subLinkType == ANY_SUBLINK)
868 : : {
869 : : ScalarArrayOpExpr *saop;
870 : :
396 akorotkov@postgresql 871 [ + + ]: 3795 : if ((saop = convert_VALUES_to_ANY(root,
872 : : sublink->testexpr,
873 : 3795 : (Query *) sublink->subselect)) != NULL)
874 : : {
875 : : /*
876 : : * The VALUES sequence was simplified. Nothing more to do
877 : : * here.
878 : : */
879 : 70 : return (Node *) saop;
880 : : }
881 : :
54 rguo@postgresql.org 882 [ + + ]:GNC 3725 : if ((j = convert_ANY_sublink_to_join(root, sublink, false,
883 : : available_rels1)) != NULL)
884 : : {
885 : : /* Yes; insert the new join node into the join tree */
5212 tgl@sss.pgh.pa.us 886 :CBC 3638 : j->larg = *jtlink1;
887 : 3638 : *jtlink1 = (Node *) j;
888 : : /* Recursively process pulled-up jointree nodes */
889 : 3638 : j->rarg = pull_up_sublinks_jointree_recurse(root,
890 : : j->rarg,
891 : : &child_rels);
892 : :
893 : : /*
894 : : * Now recursively process the pulled-up quals. Any inserted
895 : : * joins can get stacked onto either j->larg or j->rarg,
896 : : * depending on which rels they reference.
897 : : */
898 : 3638 : j->quals = pull_up_sublinks_qual_recurse(root,
899 : : j->quals,
900 : : &j->larg,
901 : : available_rels1,
902 : : &j->rarg,
903 : : child_rels);
904 : : /* Return NULL representing constant TRUE */
905 : 3638 : return NULL;
906 : : }
907 [ + + - + ]: 92 : if (available_rels2 != NULL &&
54 rguo@postgresql.org 908 :GNC 5 : (j = convert_ANY_sublink_to_join(root, sublink, false,
909 : : available_rels2)) != NULL)
910 : : {
911 : : /* Yes; insert the new join node into the join tree */
5212 tgl@sss.pgh.pa.us 912 :UBC 0 : j->larg = *jtlink2;
913 : 0 : *jtlink2 = (Node *) j;
914 : : /* Recursively process pulled-up jointree nodes */
5482 915 : 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
916 : : j->rarg,
917 : : &child_rels);
918 : :
919 : : /*
920 : : * Now recursively process the pulled-up quals. Any inserted
921 : : * joins can get stacked onto either j->larg or j->rarg,
922 : : * depending on which rels they reference.
923 : : */
924 : 0 : j->quals = pull_up_sublinks_qual_recurse(root,
925 : : j->quals,
926 : : &j->larg,
927 : : available_rels2,
928 : : &j->rarg,
929 : : child_rels);
930 : : /* Return NULL representing constant TRUE */
6278 931 : 0 : return NULL;
932 : : }
933 : : }
6473 tgl@sss.pgh.pa.us 934 [ + + ]:CBC 680 : else if (sublink->subLinkType == EXISTS_SUBLINK)
935 : : {
5212 936 [ + + ]: 630 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
937 : : available_rels1)) != NULL)
938 : : {
939 : : /* Yes; insert the new join node into the join tree */
940 : 520 : j->larg = *jtlink1;
941 : 520 : *jtlink1 = (Node *) j;
942 : : /* Recursively process pulled-up jointree nodes */
5482 943 : 520 : j->rarg = pull_up_sublinks_jointree_recurse(root,
944 : : j->rarg,
945 : : &child_rels);
946 : :
947 : : /*
948 : : * Now recursively process the pulled-up quals. Any inserted
949 : : * joins can get stacked onto either j->larg or j->rarg,
950 : : * depending on which rels they reference.
951 : : */
952 : 520 : j->quals = pull_up_sublinks_qual_recurse(root,
953 : : j->quals,
954 : : &j->larg,
955 : : available_rels1,
956 : : &j->rarg,
957 : : child_rels);
958 : : /* Return NULL representing constant TRUE */
5212 959 : 520 : return NULL;
960 : : }
961 [ + + + - ]: 126 : if (available_rels2 != NULL &&
962 : 16 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
963 : : available_rels2)) != NULL)
964 : : {
965 : : /* Yes; insert the new join node into the join tree */
966 : 16 : j->larg = *jtlink2;
967 : 16 : *jtlink2 = (Node *) j;
968 : : /* Recursively process pulled-up jointree nodes */
969 : 16 : j->rarg = pull_up_sublinks_jointree_recurse(root,
970 : : j->rarg,
971 : : &child_rels);
972 : :
973 : : /*
974 : : * Now recursively process the pulled-up quals. Any inserted
975 : : * joins can get stacked onto either j->larg or j->rarg,
976 : : * depending on which rels they reference.
977 : : */
978 : 16 : j->quals = pull_up_sublinks_qual_recurse(root,
979 : : j->quals,
980 : : &j->larg,
981 : : available_rels2,
982 : : &j->rarg,
983 : : child_rels);
984 : : /* Return NULL representing constant TRUE */
6278 985 : 16 : return NULL;
986 : : }
987 : : }
988 : : /* Else return it unmodified */
6473 989 : 231 : return node;
990 : : }
2653 991 [ + + ]: 112495 : if (is_notclause(node))
992 : : {
993 : : /* If the immediate argument of NOT is ANY or EXISTS, try to convert */
6473 994 : 11992 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
995 : : JoinExpr *j;
996 : : Relids child_rels;
997 : :
998 [ + - + + ]: 11992 : if (sublink && IsA(sublink, SubLink))
999 : : {
54 rguo@postgresql.org 1000 [ + + ]:GNC 5012 : if (sublink->subLinkType == ANY_SUBLINK)
1001 : : {
1002 [ + + ]: 210 : if ((j = convert_ANY_sublink_to_join(root, sublink, true,
1003 : : available_rels1)) != NULL)
1004 : : {
1005 : : /* Yes; insert the new join node into the join tree */
1006 : 75 : j->larg = *jtlink1;
1007 : 75 : *jtlink1 = (Node *) j;
1008 : : /* Recursively process pulled-up jointree nodes */
1009 : 75 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1010 : : j->rarg,
1011 : : &child_rels);
1012 : :
1013 : : /*
1014 : : * Now recursively process the pulled-up quals. Because
1015 : : * we are underneath a NOT, we can't pull up sublinks that
1016 : : * reference the left-hand stuff, but it's still okay to
1017 : : * pull up sublinks referencing j->rarg.
1018 : : */
1019 : 75 : j->quals = pull_up_sublinks_qual_recurse(root,
1020 : : j->quals,
1021 : : &j->rarg,
1022 : : child_rels,
1023 : : NULL, NULL);
1024 : : /* Return NULL representing constant TRUE */
1025 : 75 : return NULL;
1026 : : }
1027 [ - + - - ]: 135 : if (available_rels2 != NULL &&
54 rguo@postgresql.org 1028 :UNC 0 : (j = convert_ANY_sublink_to_join(root, sublink, true,
1029 : : available_rels2)) != NULL)
1030 : : {
1031 : : /* Yes; insert the new join node into the join tree */
1032 : 0 : j->larg = *jtlink2;
1033 : 0 : *jtlink2 = (Node *) j;
1034 : : /* Recursively process pulled-up jointree nodes */
1035 : 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1036 : : j->rarg,
1037 : : &child_rels);
1038 : :
1039 : : /*
1040 : : * Now recursively process the pulled-up quals. Because
1041 : : * we are underneath a NOT, we can't pull up sublinks that
1042 : : * reference the left-hand stuff, but it's still okay to
1043 : : * pull up sublinks referencing j->rarg.
1044 : : */
1045 : 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1046 : : j->quals,
1047 : : &j->rarg,
1048 : : child_rels,
1049 : : NULL, NULL);
1050 : : /* Return NULL representing constant TRUE */
1051 : 0 : return NULL;
1052 : : }
1053 : : }
54 rguo@postgresql.org 1054 [ + - ]:GNC 4802 : else if (sublink->subLinkType == EXISTS_SUBLINK)
1055 : : {
5212 tgl@sss.pgh.pa.us 1056 [ + + ]:CBC 4802 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
1057 : : available_rels1)) != NULL)
1058 : : {
1059 : : /* Yes; insert the new join node into the join tree */
1060 : 4793 : j->larg = *jtlink1;
1061 : 4793 : *jtlink1 = (Node *) j;
1062 : : /* Recursively process pulled-up jointree nodes */
1063 : 4793 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1064 : : j->rarg,
1065 : : &child_rels);
1066 : :
1067 : : /*
1068 : : * Now recursively process the pulled-up quals. Because
1069 : : * we are underneath a NOT, we can't pull up sublinks that
1070 : : * reference the left-hand stuff, but it's still okay to
1071 : : * pull up sublinks referencing j->rarg.
1072 : : */
1073 : 4793 : j->quals = pull_up_sublinks_qual_recurse(root,
1074 : : j->quals,
1075 : : &j->rarg,
1076 : : child_rels,
1077 : : NULL, NULL);
1078 : : /* Return NULL representing constant TRUE */
1079 : 4793 : return NULL;
1080 : : }
1081 [ - + - - ]: 9 : if (available_rels2 != NULL &&
5212 tgl@sss.pgh.pa.us 1082 :UBC 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
1083 : : available_rels2)) != NULL)
1084 : : {
1085 : : /* Yes; insert the new join node into the join tree */
1086 : 0 : j->larg = *jtlink2;
1087 : 0 : *jtlink2 = (Node *) j;
1088 : : /* Recursively process pulled-up jointree nodes */
5482 1089 : 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1090 : : j->rarg,
1091 : : &child_rels);
1092 : :
1093 : : /*
1094 : : * Now recursively process the pulled-up quals. Because
1095 : : * we are underneath a NOT, we can't pull up sublinks that
1096 : : * reference the left-hand stuff, but it's still okay to
1097 : : * pull up sublinks referencing j->rarg.
1098 : : */
1099 : 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1100 : : j->quals,
1101 : : &j->rarg,
1102 : : child_rels,
1103 : : NULL, NULL);
1104 : : /* Return NULL representing constant TRUE */
6278 1105 : 0 : return NULL;
1106 : : }
1107 : : }
1108 : : }
1109 : : /* Else return it unmodified */
6473 tgl@sss.pgh.pa.us 1110 :CBC 7124 : return node;
1111 : : }
2653 1112 [ + + ]: 100503 : if (is_andclause(node))
1113 : : {
1114 : : /* Recurse into AND clause */
8310 bruce@momjian.us 1115 : 23699 : List *newclauses = NIL;
1116 : : ListCell *l;
1117 : :
8014 neilc@samurai.com 1118 [ + - + + : 86875 : foreach(l, ((BoolExpr *) node)->args)
+ + ]
1119 : : {
1120 : 63176 : Node *oldclause = (Node *) lfirst(l);
1121 : : Node *newclause;
1122 : :
6278 tgl@sss.pgh.pa.us 1123 : 63176 : newclause = pull_up_sublinks_qual_recurse(root,
1124 : : oldclause,
1125 : : jtlink1,
1126 : : available_rels1,
1127 : : jtlink2,
1128 : : available_rels2);
1129 [ + + ]: 63176 : if (newclause)
1130 : 56125 : newclauses = lappend(newclauses, newclause);
1131 : : }
1132 : : /* We might have got back fewer clauses than we started with */
1133 [ + + ]: 23699 : if (newclauses == NIL)
1134 : 69 : return NULL;
1135 [ + + ]: 23630 : else if (list_length(newclauses) == 1)
1136 : 942 : return (Node *) linitial(newclauses);
1137 : : else
1138 : 22688 : return (Node *) make_andclause(newclauses);
1139 : : }
1140 : : /* Stop if not an AND */
8506 1141 : 76804 : return node;
1142 : : }
1143 : :
1144 : : /*
1145 : : * preprocess_function_rtes
1146 : : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
1147 : : * attempt to "inline" any that can be converted to simple subqueries.
1148 : : *
1149 : : * If an RTE_FUNCTION rtable entry invokes a set-returning SQL function that
1150 : : * contains just a simple SELECT, we can convert the rtable entry to an
1151 : : * RTE_SUBQUERY entry exposing the SELECT directly. Other sorts of functions
1152 : : * are also inline-able if they have a support function that can generate
1153 : : * the replacement sub-Query. This is especially useful if the subquery can
1154 : : * then be "pulled up" for further optimization, but we do it even if not,
1155 : : * to reduce executor overhead.
1156 : : *
1157 : : * This has to be done before we have started to do any optimization of
1158 : : * subqueries, else any such steps wouldn't get applied to subqueries
1159 : : * obtained via inlining. However, we do it after pull_up_sublinks
1160 : : * so that we can inline any functions used in SubLink subselects.
1161 : : *
1162 : : * The reason for applying const-simplification at this stage is that
1163 : : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
1164 : : * we can be sure that pull_up_constant_function() will see constants
1165 : : * if there are constants to be seen. This approach also guarantees
1166 : : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
1167 : : * preprocess_expression() to skip doing it again.
1168 : : *
1169 : : * Like most of the planner, this feels free to scribble on its input data
1170 : : * structure.
1171 : : */
1172 : : void
2469 1173 : 428697 : preprocess_function_rtes(PlannerInfo *root)
1174 : : {
1175 : : ListCell *rt;
1176 : :
6622 1177 [ + - + + : 1120235 : foreach(rt, root->parse->rtable)
+ + ]
1178 : : {
1179 : 691542 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
1180 : :
1181 [ + + ]: 691542 : if (rte->rtekind == RTE_FUNCTION)
1182 : : {
1183 : : Query *funcquery;
1184 : :
1185 : : /* Apply const-simplification */
2469 1186 : 36371 : rte->functions = (List *)
1187 : 36371 : eval_const_expressions(root, (Node *) rte->functions);
1188 : :
1189 : : /* Check safety of expansion, and expand if possible */
164 tgl@sss.pgh.pa.us 1190 :GNC 36371 : funcquery = inline_function_in_from(root, rte);
6622 tgl@sss.pgh.pa.us 1191 [ + + ]:CBC 36367 : if (funcquery)
1192 : : {
1193 : : /* Successful expansion, convert the RTE to a subquery */
1194 : 205 : rte->rtekind = RTE_SUBQUERY;
1195 : 205 : rte->subquery = funcquery;
2786 1196 : 205 : rte->security_barrier = false;
1197 : :
1198 : : /*
1199 : : * Clear fields that should not be set in a subquery RTE.
1200 : : * However, we leave rte->functions filled in for the moment,
1201 : : * in case makeWholeRowVar needs to consult it. We'll clear
1202 : : * it in setrefs.c (see add_rte_to_flat_rtable) so that this
1203 : : * abuse of the data structure doesn't escape the planner.
1204 : : */
1205 : 205 : rte->funcordinality = false;
1206 : : }
1207 : : }
1208 : : }
6622 1209 : 428693 : }
1210 : :
1211 : : /*
1212 : : * pull_up_subqueries
1213 : : * Look for subqueries in the rangetable that can be pulled up into
1214 : : * the parent query. If the subquery has no special features like
1215 : : * grouping/aggregation then we can merge it into the parent's jointree.
1216 : : * Also, subqueries that are simple UNION ALL structures can be
1217 : : * converted into "append relations".
1218 : : */
1219 : : void
4073 1220 : 428693 : pull_up_subqueries(PlannerInfo *root)
1221 : : {
1222 : : /* Top level of jointree must always be a FromExpr */
1223 [ - + ]: 428693 : Assert(IsA(root->parse->jointree, FromExpr));
1224 : : /* Recursion starts with no containing join nor appendrel */
1225 : 857386 : root->parse->jointree = (FromExpr *)
1226 : 428693 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
1227 : : NULL, NULL);
1228 : : /* We should still have a FromExpr */
1229 [ - + ]: 428693 : Assert(IsA(root->parse->jointree, FromExpr));
5014 1230 : 428693 : }
1231 : :
1232 : : /*
1233 : : * pull_up_subqueries_recurse
1234 : : * Recursive guts of pull_up_subqueries.
1235 : : *
1236 : : * This recursively processes the jointree and returns a modified jointree.
1237 : : *
1238 : : * If this jointree node is within either side of an outer join, then
1239 : : * lowest_outer_join references the lowest such JoinExpr node; otherwise
1240 : : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
1241 : : *
1242 : : * If we are looking at a member subquery of an append relation,
1243 : : * containing_appendrel describes that relation; else it is NULL.
1244 : : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
1245 : : * items, and puts some additional restrictions on what can be pulled up.
1246 : : *
1247 : : * A tricky aspect of this code is that if we pull up a subquery we have
1248 : : * to replace Vars that reference the subquery's outputs throughout the
1249 : : * parent query, including quals attached to jointree nodes above the one
1250 : : * we are currently processing! We handle this by being careful to maintain
1251 : : * validity of the jointree structure while recursing, in the following sense:
1252 : : * whenever we recurse, all qual expressions in the tree must be reachable
1253 : : * from the top level, in case the recursive call needs to modify them.
1254 : : *
1255 : : * Notice also that we can't turn pullup_replace_vars loose on the whole
1256 : : * jointree, because it'd return a mutated copy of the tree; we have to
1257 : : * invoke it just on the quals, instead. This behavior is what makes it
1258 : : * reasonable to pass lowest_outer_join as a pointer rather than some
1259 : : * more-indirect way of identifying the lowest OJ. Likewise, we don't
1260 : : * replace append_rel_list members but only their substructure, so the
1261 : : * containing_appendrel reference is safe to use.
1262 : : */
1263 : : static Node *
1264 : 1080864 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
1265 : : JoinExpr *lowest_outer_join,
1266 : : AppendRelInfo *containing_appendrel)
1267 : : {
1268 : : /* Since this function recurses, it could be driven to stack overflow. */
1230 1269 : 1080864 : check_stack_depth();
1270 : : /* Also, since it's a bit expensive, let's check for query cancel. */
1271 [ + + ]: 1080864 : CHECK_FOR_INTERRUPTS();
1272 : :
4073 1273 [ - + ]: 1080864 : Assert(jtnode != NULL);
8506 1274 [ + + ]: 1080864 : if (IsA(jtnode, RangeTblRef))
1275 : : {
1276 : 557928 : int varno = ((RangeTblRef *) jtnode)->rtindex;
7396 1277 : 557928 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
1278 : :
1279 : : /*
1280 : : * Is this a subquery RTE, and if so, is the subquery simple enough to
1281 : : * pull up?
1282 : : *
1283 : : * If we are looking at an append-relation member, we can't pull it up
1284 : : * unless is_safe_append_member says so.
1285 : : */
8030 1286 [ + + + + ]: 609118 : if (rte->rtekind == RTE_SUBQUERY &&
1930 1287 [ + + ]: 85500 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
6216 1288 [ + + ]: 9994 : (containing_appendrel == NULL ||
1289 : 9994 : is_safe_append_member(rte->subquery)))
7396 1290 : 29561 : return pull_up_simple_subquery(root, jtnode, rte,
1291 : : lowest_outer_join,
1292 : : containing_appendrel);
1293 : :
1294 : : /*
1295 : : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
1296 : : * into an "append relation".
1297 : : *
1298 : : * It's safe to do this regardless of whether this query is itself an
1299 : : * appendrel member. (If you're thinking we should try to flatten the
1300 : : * two levels of appendrel together, you're right; but we handle that
1301 : : * in set_append_rel_pathlist, not here.)
1302 : : */
1303 [ + + + + ]: 549996 : if (rte->rtekind == RTE_SUBQUERY &&
1304 : 21629 : is_simple_union_all(rte->subquery))
1305 : 4057 : return pull_up_simple_union_all(root, jtnode, rte);
1306 : :
1307 : : /*
1308 : : * Or perhaps it's a simple VALUES RTE?
1309 : : *
1310 : : * We don't allow VALUES pullup below an outer join nor into an
1311 : : * appendrel (such cases are impossible anyway at the moment).
1312 : : */
4073 1313 [ + + + - ]: 524310 : if (rte->rtekind == RTE_VALUES &&
1314 [ + - ]: 10652 : lowest_outer_join == NULL &&
1315 [ + + ]: 10652 : containing_appendrel == NULL &&
2654 1316 : 10652 : is_simple_values(root, rte))
4073 1317 : 3783 : return pull_up_simple_values(root, jtnode, rte);
1318 : :
1319 : : /*
1320 : : * Or perhaps it's a FUNCTION RTE that we could inline?
1321 : : */
2469 1322 [ + + ]: 520527 : if (rte->rtekind == RTE_FUNCTION)
1323 : 36162 : return pull_up_constant_function(root, jtnode, rte,
1324 : : containing_appendrel);
1325 : :
1326 : : /* Otherwise, do nothing at this node. */
1327 : : }
8506 1328 [ + + ]: 522936 : else if (IsA(jtnode, FromExpr))
1329 : : {
1330 : 439166 : FromExpr *f = (FromExpr *) jtnode;
1331 : : ListCell *l;
1332 : :
6216 1333 [ - + ]: 439166 : Assert(containing_appendrel == NULL);
1334 : : /* Recursively transform all the child nodes */
8506 1335 [ + + + + : 910765 : foreach(l, f->fromlist)
+ + ]
1336 : : {
5014 1337 : 471599 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
1338 : : lowest_outer_join,
1339 : : NULL);
1340 : : }
1341 : : }
8506 1342 [ + - ]: 83770 : else if (IsA(jtnode, JoinExpr))
1343 : : {
1344 : 83770 : JoinExpr *j = (JoinExpr *) jtnode;
1345 : :
6216 1346 [ - + ]: 83770 : Assert(containing_appendrel == NULL);
1347 : : /* Recurse, being careful to tell myself when inside outer join */
8506 1348 [ + + + + : 83770 : switch (j->jointype)
- ]
1349 : : {
1350 : 37325 : case JOIN_INNER:
5014 1351 : 37325 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1352 : : lowest_outer_join,
1353 : : NULL);
1354 : 37325 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1355 : : lowest_outer_join,
1356 : : NULL);
8506 1357 : 37325 : break;
1358 : 44607 : case JOIN_LEFT:
1359 : : case JOIN_SEMI:
1360 : : case JOIN_ANTI:
5014 1361 : 44607 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1362 : : j,
1363 : : NULL);
1364 : 44607 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1365 : : j,
1366 : : NULL);
8506 1367 : 44607 : break;
1368 : 870 : case JOIN_FULL:
5014 1369 : 870 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1370 : : j,
1371 : : NULL);
1372 : 870 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1373 : : j,
1374 : : NULL);
8506 1375 : 870 : break;
1376 : 968 : case JOIN_RIGHT:
5014 1377 : 968 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1378 : : j,
1379 : : NULL);
1380 : 968 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1381 : : j,
1382 : : NULL);
8506 1383 : 968 : break;
8506 tgl@sss.pgh.pa.us 1384 :UBC 0 : default:
8320 1385 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
1386 : : (int) j->jointype);
1387 : : break;
1388 : : }
1389 : : }
1390 : : else
1391 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
1392 : : (int) nodeTag(jtnode));
8506 tgl@sss.pgh.pa.us 1393 :CBC 1007301 : return jtnode;
1394 : : }
1395 : :
1396 : : /*
1397 : : * pull_up_simple_subquery
1398 : : * Attempt to pull up a single simple subquery.
1399 : : *
1400 : : * jtnode is a RangeTblRef that has been tentatively identified as a simple
1401 : : * subquery by pull_up_subqueries. We return the replacement jointree node,
1402 : : * or jtnode itself if we determine that the subquery can't be pulled up
1403 : : * after all.
1404 : : *
1405 : : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1406 : : * as for pull_up_subqueries_recurse.
1407 : : */
1408 : : static Node *
7396 1409 : 29561 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1410 : : JoinExpr *lowest_outer_join,
1411 : : AppendRelInfo *containing_appendrel)
1412 : : {
1413 : 29561 : Query *parse = root->parse;
1414 : 29561 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1415 : : Query *subquery;
1416 : : PlannerInfo *subroot;
1417 : : int rtoffset;
1418 : : pullup_replace_vars_context rvcontext;
1419 : : ListCell *lc;
1420 : :
1421 : : /*
1422 : : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1423 : : * be left unchanged in case we decide below that we can't pull it up
1424 : : * after all.
1425 : : */
1426 : 29561 : subquery = copyObject(rte->subquery);
1427 : :
1428 : : /*
1429 : : * Create a PlannerInfo data structure for this subquery.
1430 : : *
1431 : : * NOTE: the next few steps should match the first processing in
1432 : : * subquery_planner(). Can we refactor to avoid code duplication, or
1433 : : * would that just make things uglier?
1434 : : */
1435 : 29561 : subroot = makeNode(PlannerInfo);
1436 : 29561 : subroot->parse = subquery;
7015 1437 : 29561 : subroot->glob = root->glob;
1438 : 29561 : subroot->query_level = root->query_level;
210 rhaas@postgresql.org 1439 :GNC 29561 : subroot->plan_name = root->plan_name;
40 1440 : 29561 : subroot->alternative_plan_name = root->alternative_plan_name;
6422 tgl@sss.pgh.pa.us 1441 :CBC 29561 : subroot->parent_root = root->parent_root;
4990 1442 : 29561 : subroot->plan_params = NIL;
3920 1443 : 29561 : subroot->outer_params = NULL;
7045 1444 : 29561 : subroot->planner_cxt = CurrentMemoryContext;
7015 1445 : 29561 : subroot->init_plans = NIL;
6422 1446 : 29561 : subroot->cte_plan_ids = NIL;
4339 1447 : 29561 : subroot->multiexpr_params = NIL;
1191 1448 : 29561 : subroot->join_domains = NIL;
6622 1449 : 29561 : subroot->eq_classes = NIL;
2480 drowley@postgresql.o 1450 : 29561 : subroot->ec_merging_done = false;
1191 tgl@sss.pgh.pa.us 1451 : 29561 : subroot->last_rinfo_serial = 0;
1861 1452 : 29561 : subroot->all_result_relids = NULL;
1453 : 29561 : subroot->leaf_result_relids = NULL;
7396 1454 : 29561 : subroot->append_rel_list = NIL;
1861 1455 : 29561 : subroot->row_identity_vars = NIL;
6035 1456 : 29561 : subroot->rowMarks = NIL;
3711 1457 : 29561 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
3704 1458 : 29561 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1203 1459 : 29561 : subroot->processed_groupClause = NIL;
1460 : 29561 : subroot->processed_distinctClause = NIL;
3711 1461 : 29561 : subroot->processed_tlist = NIL;
1861 1462 : 29561 : subroot->update_colnos = NIL;
3711 1463 : 29561 : subroot->grouping_map = NULL;
1464 : 29561 : subroot->minmax_aggs = NIL;
3394 1465 : 29561 : subroot->qual_security_level = 0;
1357 1466 : 29561 : subroot->placeholdersFrozen = false;
6422 1467 : 29561 : subroot->hasRecursion = false;
258 rhaas@postgresql.org 1468 :GNC 29561 : subroot->assumeReplanning = false;
6422 tgl@sss.pgh.pa.us 1469 :CBC 29561 : subroot->wt_param_id = -1;
3711 1470 : 29561 : subroot->non_recursive_path = NULL;
1471 : : /* We don't currently need a top JoinDomain for the subroot */
1472 : :
1473 : : /* No CTEs to worry about */
6422 1474 [ - + ]: 29561 : Assert(subquery->cteList == NIL);
1475 : :
1476 : : /*
1477 : : * Scan the rangetable for relation RTEs and retrieve the necessary
1478 : : * catalog information for each relation. Using this information, clear
1479 : : * the inh flag for any relation that has no children, collect not-null
1480 : : * attribute numbers for any relation that has column not-null
1481 : : * constraints, and expand virtual generated columns for any relation that
1482 : : * contains them.
1483 : : */
287 rguo@postgresql.org 1484 :GNC 29561 : subquery = subroot->parse = preprocess_relation_rtes(subroot);
1485 : :
1486 : : /*
1487 : : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1488 : : * that we don't need so many special cases to deal with that situation.
1489 : : */
2654 tgl@sss.pgh.pa.us 1490 :CBC 29561 : replace_empty_jointree(subquery);
1491 : :
1492 : : /*
1493 : : * Pull up any SubLinks within the subquery's quals, so that we don't
1494 : : * leave unoptimized SubLinks behind.
1495 : : */
7396 1496 [ + + ]: 29561 : if (subquery->hasSubLinks)
6470 1497 : 1612 : pull_up_sublinks(subroot);
1498 : :
1499 : : /*
1500 : : * Similarly, preprocess its function RTEs to inline any set-returning
1501 : : * functions in its rangetable.
1502 : : */
2469 1503 : 29561 : preprocess_function_rtes(subroot);
1504 : :
1505 : : /*
1506 : : * Recursively pull up the subquery's subqueries, so that
1507 : : * pull_up_subqueries' processing is complete for its jointree and
1508 : : * rangetable.
1509 : : *
1510 : : * Note: it's okay that the subquery's recursion starts with NULL for
1511 : : * containing-join info, even if we are within an outer join in the upper
1512 : : * query; the lower query starts with a clean slate for outer-join
1513 : : * semantics. Likewise, we needn't pass down appendrel state.
1514 : : */
4073 1515 : 29561 : pull_up_subqueries(subroot);
1516 : :
1517 : : /*
1518 : : * Now we must recheck whether the subquery is still simple enough to pull
1519 : : * up. If not, abandon processing it.
1520 : : *
1521 : : * We don't really need to recheck all the conditions involved, but it's
1522 : : * easier just to keep this "if" looking the same as the one in
1523 : : * pull_up_subqueries_recurse.
1524 : : */
1930 1525 [ + + + + ]: 34682 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
6216 1526 [ + + ]: 5245 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1527 : : {
1528 : : /* good to go */
1529 : : }
1530 : : else
1531 : : {
1532 : : /*
1533 : : * Give up, return unmodified RangeTblRef.
1534 : : *
1535 : : * Note: The work we just did will be redone when the subquery gets
1536 : : * planned on its own. Perhaps we could avoid that by storing the
1537 : : * modified subquery back into the rangetable, but I'm not gonna risk
1538 : : * it now.
1539 : : */
7396 1540 : 134 : return jtnode;
1541 : : }
1542 : :
1543 : : /*
1544 : : * We must flatten any join alias Vars in the subquery's targetlist,
1545 : : * because pulling up the subquery's subqueries might have changed their
1546 : : * expansions into arbitrary expressions, which could affect
1547 : : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1548 : : * are needed for tlist entries. (Likely it'd be better to do
1549 : : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1550 : : * maybe even in the rewriter; but for now let's just fix this case here.)
1551 : : */
4547 1552 : 29427 : subquery->targetList = (List *)
1191 1553 : 29427 : flatten_join_alias_vars(subroot, subroot->parse,
1554 : 29427 : (Node *) subquery->targetList);
1555 : :
1556 : : /*
1557 : : * Adjust level-0 varnos in subquery so that we can append its rangetable
1558 : : * to upper query's. We have to fix the subquery's append_rel_list as
1559 : : * well.
1560 : : */
7396 1561 : 29427 : rtoffset = list_length(parse->rtable);
1562 : 29427 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1563 : 29427 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1564 : :
1565 : : /*
1566 : : * Upper-level vars in subquery are now one level closer to their parent
1567 : : * than before.
1568 : : */
1569 : 29427 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1570 : 29427 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1571 : :
1572 : : /*
1573 : : * The subquery's targetlist items are now in the appropriate form to
1574 : : * insert into the top query, except that we may need to wrap them in
1575 : : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1576 : : * (Note that we should include the subquery's inner joins in relids,
1577 : : * since it may include join alias vars referencing them.)
1578 : : */
6089 1579 : 29427 : rvcontext.root = root;
1580 : 29427 : rvcontext.targetlist = subquery->targetList;
1581 : 29427 : rvcontext.target_rte = rte;
434 rguo@postgresql.org 1582 : 29427 : rvcontext.result_relation = 0;
4644 tgl@sss.pgh.pa.us 1583 [ + + ]: 29427 : if (rte->lateral)
1584 : : {
1585 : 1346 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1586 : : true, true);
521 1587 : 1346 : rvcontext.nullinfo = get_nullingrels(parse);
1588 : : }
1589 : : else /* won't need these values */
1590 : : {
4644 1591 : 28081 : rvcontext.relids = NULL;
521 1592 : 28081 : rvcontext.nullinfo = NULL;
1593 : : }
6089 1594 : 29427 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1595 : 29427 : rvcontext.varno = varno;
1596 : : /* this flag will be set below, if needed */
418 rguo@postgresql.org 1597 : 29427 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1598 : : /* initialize cache array with indexes 0 .. length(tlist) */
6089 tgl@sss.pgh.pa.us 1599 : 29427 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1600 : : sizeof(Node *));
1601 : :
1602 : : /*
1603 : : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1604 : : * each expression of the subquery's targetlist items. This ensures that
1605 : : * expressions retain their separate identity so that they will match
1606 : : * grouping set columns when appropriate. (It'd be sufficient to wrap
1607 : : * values used in grouping set columns, and do so only in non-aggregated
1608 : : * portions of the tlist and havingQual, but that would require a lot of
1609 : : * infrastructure that pullup_replace_vars hasn't currently got.)
1610 : : */
3035 1611 [ + + ]: 29427 : if (parse->groupingSets)
418 rguo@postgresql.org 1612 : 386 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1613 : :
1614 : : /*
1615 : : * Replace all of the top query's references to the subquery's outputs
1616 : : * with copies of the adjusted subtlist items, being careful not to
1617 : : * replace any of the jointree structure.
1618 : : */
2469 tgl@sss.pgh.pa.us 1619 : 29427 : perform_pullup_replace_vars(root, &rvcontext,
1620 : : containing_appendrel);
1621 : :
1622 : : /*
1623 : : * If the subquery had a LATERAL marker, propagate that to any of its
1624 : : * child RTEs that could possibly now contain lateral cross-references.
1625 : : * The children might or might not contain any actual lateral
1626 : : * cross-references, but we have to mark the pulled-up child RTEs so that
1627 : : * later planner stages will check for such.
1628 : : */
5014 1629 [ + + ]: 29427 : if (rte->lateral)
1630 : : {
1631 [ + - + + : 3561 : foreach(lc, subquery->rtable)
+ + ]
1632 : : {
1633 : 2215 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1634 : :
1635 [ + + + - : 2215 : switch (child_rte->rtekind)
- ]
1636 : : {
3937 1637 : 1525 : case RTE_RELATION:
1638 [ + + ]: 1525 : if (child_rte->tablesample)
1639 : 31 : child_rte->lateral = true;
1640 : 1525 : break;
5014 1641 : 247 : case RTE_SUBQUERY:
1642 : : case RTE_FUNCTION:
1643 : : case RTE_VALUES:
1644 : : case RTE_TABLEFUNC:
1645 : 247 : child_rte->lateral = true;
1646 : 247 : break;
1647 : 443 : case RTE_JOIN:
1648 : : case RTE_CTE:
1649 : : case RTE_NAMEDTUPLESTORE:
1650 : : case RTE_RESULT:
1651 : : case RTE_GROUP:
1652 : : /* these can't contain any lateral references */
1653 : 443 : break;
50 peter@eisentraut.org 1654 :UNC 0 : case RTE_GRAPH_TABLE:
1655 : : /* shouldn't happen here */
1656 : 0 : Assert(false);
1657 : : break;
1658 : : }
1659 : : }
1660 : : }
1661 : :
1662 : : /*
1663 : : * Now append the adjusted rtable entries and their perminfos to upper
1664 : : * query. (We hold off until after fixing the upper rtable entries; no
1665 : : * point in running that code on the subquery ones too.)
1666 : : */
1246 alvherre@alvh.no-ip. 1667 :CBC 29427 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1668 : : subquery->rtable, subquery->rteperminfos);
1669 : :
1670 : : /*
1671 : : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1672 : : * adjusted the marker rtindexes, so just concat the lists.)
1673 : : */
7396 tgl@sss.pgh.pa.us 1674 : 29427 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1675 : :
1676 : : /*
1677 : : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1678 : : * parent query. (This could perhaps be done by pullup_replace_vars(),
1679 : : * but it seems cleaner to use two passes.) Note in particular that any
1680 : : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1681 : : * adjusted, so having created them with the subquery's varno is correct.
1682 : : *
1683 : : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1684 : : * already checked that this won't require introducing multiple subrelids
1685 : : * into the single-slot AppendRelInfo structs.
1686 : : */
1230 1687 [ + + + + ]: 29427 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1688 : : {
1689 : : Relids subrelids;
1690 : :
1191 1691 : 6853 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1692 : : true, false);
1230 1693 [ + + ]: 6853 : if (root->glob->lastPHId != 0)
1694 : 1762 : substitute_phv_relids((Node *) parse, varno, subrelids);
1695 : 6853 : fix_append_rel_relids(root, varno, subrelids);
1696 : : }
1697 : :
1698 : : /*
1699 : : * And now add subquery's AppendRelInfos to our list.
1700 : : */
7396 1701 : 58854 : root->append_rel_list = list_concat(root->append_rel_list,
1702 : 29427 : subroot->append_rel_list);
1703 : :
1704 : : /*
1705 : : * We don't have to do the equivalent bookkeeping for outer-join info,
1706 : : * because that hasn't been set up yet. placeholder_list likewise.
1707 : : */
6473 1708 [ - + ]: 29427 : Assert(root->join_info_list == NIL);
1709 [ - + ]: 29427 : Assert(subroot->join_info_list == NIL);
6404 1710 [ - + ]: 29427 : Assert(root->placeholder_list == NIL);
1711 [ - + ]: 29427 : Assert(subroot->placeholder_list == NIL);
1712 : :
1713 : : /*
1714 : : * We no longer need the RTE's copy of the subquery's query tree. Getting
1715 : : * rid of it saves nothing in particular so far as this level of query is
1716 : : * concerned; but if this query level is in turn pulled up into a parent,
1717 : : * we'd waste cycles copying the now-unused query tree.
1718 : : */
1764 1719 : 29427 : rte->subquery = NULL;
1720 : :
1721 : : /*
1722 : : * Miscellaneous housekeeping.
1723 : : *
1724 : : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1725 : : * if it copied any SubLinks out of the subquery's targetlist, we still
1726 : : * could have SubLinks added to the query in the expressions of FUNCTION
1727 : : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1728 : : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1729 : : */
7396 1730 : 29427 : parse->hasSubLinks |= subquery->hasSubLinks;
1731 : :
1732 : : /* If subquery had any RLS conditions, now main query does too */
3463 1733 : 29427 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1734 : :
1735 : : /*
1736 : : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1737 : : * hasTargetSRFs, so no work needed on those flags
1738 : : */
1739 : :
1740 : : /*
1741 : : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1742 : : * in parent's jointree; or, if the FromExpr is degenerate, just return
1743 : : * its single member.
1744 : : */
2654 1745 [ - + ]: 29427 : Assert(IsA(subquery->jointree, FromExpr));
1746 [ - + ]: 29427 : Assert(subquery->jointree->fromlist != NIL);
1747 [ + + + + ]: 54186 : if (subquery->jointree->quals == NULL &&
1748 : 24759 : list_length(subquery->jointree->fromlist) == 1)
1749 : 24503 : return (Node *) linitial(subquery->jointree->fromlist);
1750 : :
7396 1751 : 4924 : return (Node *) subquery->jointree;
1752 : : }
1753 : :
1754 : : /*
1755 : : * pull_up_simple_union_all
1756 : : * Pull up a single simple UNION ALL subquery.
1757 : : *
1758 : : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1759 : : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1760 : : * build an "append relation" for the union set. The result value is just
1761 : : * jtnode, since we don't actually need to change the query jointree.
1762 : : */
1763 : : static Node *
1764 : 4057 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1765 : : {
1766 : 4057 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1767 : 4057 : Query *subquery = rte->subquery;
5015 1768 : 4057 : int rtoffset = list_length(root->parse->rtable);
1769 : : List *rtable;
1770 : :
1771 : : /*
1772 : : * Make a modifiable copy of the subquery's rtable, so we can adjust
1773 : : * upper-level Vars in it. There are no such Vars in the setOperations
1774 : : * tree proper, so fixing the rtable should be sufficient.
1775 : : */
1776 : 4057 : rtable = copyObject(subquery->rtable);
1777 : :
1778 : : /*
1779 : : * Upper-level vars in subquery are now one level closer to their parent
1780 : : * than before. We don't have to worry about offsetting varnos, though,
1781 : : * because the UNION leaf queries can't cross-reference each other.
1782 : : */
6473 heikki.linnakangas@i 1783 : 4057 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1784 : :
1785 : : /*
1786 : : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1787 : : * its children. The individual children might or might not contain any
1788 : : * actual lateral cross-references, but we have to mark the pulled-up
1789 : : * child RTEs so that later planner stages will check for such.
1790 : : */
5015 tgl@sss.pgh.pa.us 1791 [ + + ]: 4057 : if (rte->lateral)
1792 : : {
1793 : : ListCell *rt;
1794 : :
1795 [ + - + + : 1063 : foreach(rt, rtable)
+ + ]
1796 : : {
1797 : 827 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1798 : :
1799 [ - + ]: 827 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1800 : 827 : child_rte->lateral = true;
1801 : : }
1802 : : }
1803 : :
1804 : : /*
1805 : : * Append child RTEs (and their perminfos) to parent rtable.
1806 : : */
1246 alvherre@alvh.no-ip. 1807 : 4057 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1808 : : rtable, subquery->rteperminfos);
1809 : :
1810 : : /*
1811 : : * Recursively scan the subquery's setOperations tree and add
1812 : : * AppendRelInfo nodes for leaf subqueries to the parent's
1813 : : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1814 : : */
7396 tgl@sss.pgh.pa.us 1815 [ - + ]: 4057 : Assert(subquery->setOperations);
6473 heikki.linnakangas@i 1816 : 4057 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1817 : : rtoffset);
1818 : :
1819 : : /*
1820 : : * Mark the parent as an append relation.
1821 : : */
7396 tgl@sss.pgh.pa.us 1822 : 4057 : rte->inh = true;
1823 : :
1824 : 4057 : return jtnode;
1825 : : }
1826 : :
1827 : : /*
1828 : : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1829 : : *
1830 : : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1831 : : * apply pull_up_subqueries to the leaf query.
1832 : : *
1833 : : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1834 : : * contains references to all the setop output columns. When called from
1835 : : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1836 : : * the parent Query we are pulling up into.
1837 : : *
1838 : : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1839 : : *
1840 : : * The child RTEs have already been copied to the parent. childRToffset
1841 : : * tells us where in the parent's range table they were copied. When called
1842 : : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1843 : : * were already in root->parse->rtable and no RT index adjustment is needed.
1844 : : */
1845 : : static void
1846 : 21461 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1847 : : Query *setOpQuery, int childRToffset)
1848 : : {
1849 [ + + ]: 21461 : if (IsA(setOp, RangeTblRef))
1850 : : {
1851 : 13032 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1852 : : int childRTindex;
1853 : : AppendRelInfo *appinfo;
1854 : :
1855 : : /*
1856 : : * Calculate the index in the parent's range table
1857 : : */
6473 heikki.linnakangas@i 1858 : 13032 : childRTindex = childRToffset + rtr->rtindex;
1859 : :
1860 : : /*
1861 : : * Build a suitable AppendRelInfo, and attach to parent's list.
1862 : : */
7396 tgl@sss.pgh.pa.us 1863 : 13032 : appinfo = makeNode(AppendRelInfo);
1864 : 13032 : appinfo->parent_relid = parentRTindex;
1865 : 13032 : appinfo->child_relid = childRTindex;
1866 : 13032 : appinfo->parent_reltype = InvalidOid;
1867 : 13032 : appinfo->child_reltype = InvalidOid;
2346 1868 : 13032 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
7396 1869 : 13032 : appinfo->parent_reloid = InvalidOid;
1870 : 13032 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1871 : :
1872 : : /*
1873 : : * Recursively apply pull_up_subqueries to the new child RTE. (We
1874 : : * must build the AppendRelInfo first, because this will modify it;
1875 : : * indeed, that's the only part of the upper query where Vars
1876 : : * referencing childRTindex can exist at this point.)
1877 : : *
1878 : : * Note that we can pass NULL for containing-join info even if we're
1879 : : * actually under an outer join, because the child's expressions
1880 : : * aren't going to propagate up to the join. Also, we ignore the
1881 : : * possibility that pull_up_subqueries_recurse() returns a different
1882 : : * jointree node than what we pass it; if it does, the important thing
1883 : : * is that it replaced the child relid in the AppendRelInfo node.
1884 : : */
1885 : 13032 : rtr = makeNode(RangeTblRef);
1886 : 13032 : rtr->rtindex = childRTindex;
5014 1887 : 13032 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1888 : : NULL, appinfo);
1889 : : }
7396 1890 [ + - ]: 8429 : else if (IsA(setOp, SetOperationStmt))
1891 : : {
1892 : 8429 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1893 : :
1894 : : /* Recurse to reach leaf queries */
6473 heikki.linnakangas@i 1895 : 8429 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1896 : : childRToffset);
1897 : 8429 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1898 : : childRToffset);
1899 : : }
1900 : : else
1901 : : {
7396 tgl@sss.pgh.pa.us 1902 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
1903 : : (int) nodeTag(setOp));
1904 : : }
7396 tgl@sss.pgh.pa.us 1905 :CBC 21461 : }
1906 : :
1907 : : /*
1908 : : * make_setop_translation_list
1909 : : * Build the list of translations from parent Vars to child Vars for
1910 : : * a UNION ALL member. (At this point it's just a simple list of
1911 : : * referencing Vars, but if we succeed in pulling up the member
1912 : : * subquery, the Vars will get replaced by pulled-up expressions.)
1913 : : * Also create the rather trivial reverse-translation array.
1914 : : */
1915 : : static void
1693 1916 : 13032 : make_setop_translation_list(Query *query, int newvarno,
1917 : : AppendRelInfo *appinfo)
1918 : : {
7396 1919 : 13032 : List *vars = NIL;
1920 : : AttrNumber *pcolnos;
1921 : : ListCell *l;
1922 : :
1923 : : /* Initialize reverse-translation array with all entries zero */
1924 : : /* (entries for resjunk columns will stay that way) */
2346 1925 : 13032 : appinfo->num_child_cols = list_length(query->targetList);
1926 : 13032 : appinfo->parent_colnos = pcolnos =
1927 : 13032 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1928 : :
7396 1929 [ + + + + : 56487 : foreach(l, query->targetList)
+ + ]
1930 : : {
1931 : 43455 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1932 : :
1933 [ - + ]: 43455 : if (tle->resjunk)
7396 tgl@sss.pgh.pa.us 1934 :UBC 0 : continue;
1935 : :
5730 peter_e@gmx.net 1936 :CBC 43455 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
2346 tgl@sss.pgh.pa.us 1937 : 43455 : pcolnos[tle->resno - 1] = tle->resno;
1938 : : }
1939 : :
1940 : 13032 : appinfo->translated_vars = vars;
7396 1941 : 13032 : }
1942 : :
1943 : : /*
1944 : : * is_simple_subquery
1945 : : * Check a subquery in the range table to see if it's simple enough
1946 : : * to pull up into the parent query.
1947 : : *
1948 : : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1949 : : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1950 : : * processed copy of that.)
1951 : : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1952 : : */
1953 : : static bool
1930 1954 : 80751 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1955 : : JoinExpr *lowest_outer_join)
1956 : : {
1957 : : /*
1958 : : * Let's just make sure it's a valid subselect ...
1959 : : */
8506 1960 [ + - ]: 80751 : if (!IsA(subquery, Query) ||
3398 1961 [ - + ]: 80751 : subquery->commandType != CMD_SELECT)
8320 tgl@sss.pgh.pa.us 1962 [ # # ]:UBC 0 : elog(ERROR, "subquery is bogus");
1963 : :
1964 : : /*
1965 : : * Can't currently pull up a query with setops (unless it's simple UNION
1966 : : * ALL, which is handled by a different code path). Maybe after querytree
1967 : : * redesign...
1968 : : */
8506 tgl@sss.pgh.pa.us 1969 [ + + ]:CBC 80751 : if (subquery->setOperations)
1970 : 4688 : return false;
1971 : :
1972 : : /*
1973 : : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1974 : : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1975 : : *
1976 : : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1977 : : * clauses, because pullup would cause the locking to occur semantically
1978 : : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1979 : : * that case the locking was originally declared in the upper query
1980 : : * anyway.
1981 : : */
1982 [ + + ]: 76063 : if (subquery->hasAggs ||
6337 1983 [ + + ]: 74565 : subquery->hasWindowFuncs ||
3521 1984 [ + + ]: 74244 : subquery->hasTargetSRFs ||
8506 1985 [ + + ]: 70591 : subquery->groupClause ||
4007 andres@anarazel.de 1986 [ + + ]: 70507 : subquery->groupingSets ||
8506 tgl@sss.pgh.pa.us 1987 [ + - ]: 70477 : subquery->havingQual ||
1988 [ + + ]: 70477 : subquery->sortClause ||
1989 [ + + ]: 69739 : subquery->distinctClause ||
1990 [ + + ]: 69162 : subquery->limitOffset ||
6422 1991 [ + + ]: 68777 : subquery->limitCount ||
6033 1992 [ + + ]: 68497 : subquery->hasForUpdate ||
6422 1993 [ + + ]: 65228 : subquery->cteList)
8506 1994 : 10980 : return false;
1995 : :
1996 : : /*
1997 : : * Don't pull up if the RTE represents a security-barrier view; we
1998 : : * couldn't prevent information leakage once the RTE's Vars are scattered
1999 : : * about in the upper query.
2000 : : */
5014 2001 [ + + ]: 65083 : if (rte->security_barrier)
5019 2002 : 973 : return false;
2003 : :
2004 : : /*
2005 : : * If the subquery is LATERAL, check for pullup restrictions from that.
2006 : : */
4642 2007 [ + + ]: 64110 : if (rte->lateral)
2008 : : {
2009 : : bool restricted;
2010 : : Relids safe_upper_varnos;
2011 : :
2012 : : /*
2013 : : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
2014 : : * references to rels outside a higher outer join (including the case
2015 : : * where the outer join is within the subquery itself). In such a
2016 : : * case, pulling up would result in a situation where we need to
2017 : : * postpone quals from below an outer join to above it, which is
2018 : : * probably completely wrong and in any case is a complication that
2019 : : * doesn't seem worth addressing at the moment.
2020 : : */
2021 [ + + ]: 3404 : if (lowest_outer_join != NULL)
2022 : : {
2023 : 1010 : restricted = true;
2024 : 1010 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
2025 : : true, true);
2026 : : }
2027 : : else
2028 : : {
2029 : 2394 : restricted = false;
2030 : 2394 : safe_upper_varnos = NULL; /* doesn't matter */
2031 : : }
2032 : :
1930 2033 [ + + ]: 3404 : if (jointree_contains_lateral_outer_refs(root,
2034 : 3404 : (Node *) subquery->jointree,
2035 : : restricted, safe_upper_varnos))
5014 2036 : 20 : return false;
2037 : :
2038 : : /*
2039 : : * If there's an outer join above the LATERAL subquery, also disallow
2040 : : * pullup if the subquery's targetlist has any references to rels
2041 : : * outside the outer join, since these might get pulled into quals
2042 : : * above the subquery (but in or below the outer join) and then lead
2043 : : * to qual-postponement issues similar to the case checked for above.
2044 : : * (We wouldn't need to prevent pullup if no such references appear in
2045 : : * outer-query quals, but we don't have enough info here to check
2046 : : * that. Also, maybe this restriction could be removed if we forced
2047 : : * such refs to be wrapped in PlaceHolderVars, even when they're below
2048 : : * the nearest outer join? But it's a pretty hokey usage, so not
2049 : : * clear this is worth sweating over.)
2050 : : *
2051 : : * If you change this, see also the comments about lateral references
2052 : : * in pullup_replace_vars_callback().
2053 : : */
4642 2054 [ + + ]: 3384 : if (lowest_outer_join != NULL)
2055 : : {
1930 2056 : 1010 : Relids lvarnos = pull_varnos_of_level(root,
2057 : 1010 : (Node *) subquery->targetList,
2058 : : 1);
2059 : :
4642 2060 [ + + ]: 1010 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
2061 : 10 : return false;
2062 : : }
2063 : : }
2064 : :
2065 : : /*
2066 : : * Don't pull up a subquery that has any volatile functions in its
2067 : : * targetlist. Otherwise we might introduce multiple evaluations of these
2068 : : * functions, if they get copied to multiple places in the upper query,
2069 : : * leading to surprising results. (Note: the PlaceHolderVar mechanism
2070 : : * doesn't quite guarantee single evaluation; else we could pull up anyway
2071 : : * and just wrap such items in PlaceHolderVars ...)
2072 : : */
7199 2073 [ + + ]: 64080 : if (contain_volatile_functions((Node *) subquery->targetList))
8506 2074 : 219 : return false;
2075 : :
4073 2076 : 63861 : return true;
2077 : : }
2078 : :
2079 : : /*
2080 : : * pull_up_simple_values
2081 : : * Pull up a single simple VALUES RTE.
2082 : : *
2083 : : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
2084 : : * by pull_up_subqueries. We always return a RangeTblRef representing a
2085 : : * RESULT RTE to replace it (all failure cases should have been detected by
2086 : : * is_simple_values()). Actually, what we return is just jtnode, because
2087 : : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
2088 : : *
2089 : : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
2090 : : * possible usage of VALUES RTEs, we do not need the remaining parameters
2091 : : * of pull_up_subqueries_recurse.
2092 : : */
2093 : : static Node *
2094 : 3783 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
2095 : : {
2096 : 3783 : Query *parse = root->parse;
2097 : 3783 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2098 : : List *values_list;
2099 : : List *tlist;
2100 : : AttrNumber attrno;
2101 : : pullup_replace_vars_context rvcontext;
2102 : : ListCell *lc;
2103 : :
2104 [ - + ]: 3783 : Assert(rte->rtekind == RTE_VALUES);
2105 [ - + ]: 3783 : Assert(list_length(rte->values_lists) == 1);
2106 : :
2107 : : /*
2108 : : * Need a modifiable copy of the VALUES list to hack on, just in case it's
2109 : : * multiply referenced.
2110 : : */
3344 peter_e@gmx.net 2111 : 3783 : values_list = copyObject(linitial(rte->values_lists));
2112 : :
2113 : : /*
2114 : : * The VALUES RTE can't contain any Vars of level zero, let alone any that
2115 : : * are join aliases, so no need to flatten join alias Vars.
2116 : : */
4073 tgl@sss.pgh.pa.us 2117 [ - + ]: 3783 : Assert(!contain_vars_of_level((Node *) values_list, 0));
2118 : :
2119 : : /*
2120 : : * Set up required context data for pullup_replace_vars. In particular,
2121 : : * we have to make the VALUES list look like a subquery targetlist.
2122 : : */
2123 : 3783 : tlist = NIL;
2124 : 3783 : attrno = 1;
2125 [ + + + + : 8082 : foreach(lc, values_list)
+ + ]
2126 : : {
2127 : 4299 : tlist = lappend(tlist,
2128 : 4299 : makeTargetEntry((Expr *) lfirst(lc),
2129 : : attrno,
2130 : : NULL,
2131 : : false));
2132 : 4299 : attrno++;
2133 : : }
2134 : 3783 : rvcontext.root = root;
2135 : 3783 : rvcontext.targetlist = tlist;
2136 : 3783 : rvcontext.target_rte = rte;
434 rguo@postgresql.org 2137 : 3783 : rvcontext.result_relation = 0;
521 tgl@sss.pgh.pa.us 2138 : 3783 : rvcontext.relids = NULL; /* can't be any lateral references here */
2139 : 3783 : rvcontext.nullinfo = NULL;
4073 2140 : 3783 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2141 : 3783 : rvcontext.varno = varno;
418 rguo@postgresql.org 2142 : 3783 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2143 : : /* initialize cache array with indexes 0 .. length(tlist) */
4073 tgl@sss.pgh.pa.us 2144 : 3783 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
2145 : : sizeof(Node *));
2146 : :
2147 : : /*
2148 : : * Replace all of the top query's references to the RTE's outputs with
2149 : : * copies of the adjusted VALUES expressions, being careful not to replace
2150 : : * any of the jointree structure. We can assume there's no outer joins or
2151 : : * appendrels in the dummy Query that surrounds a VALUES RTE.
2152 : : */
1191 2153 : 3783 : perform_pullup_replace_vars(root, &rvcontext, NULL);
2154 : :
2155 : : /*
2156 : : * There should be no appendrels to fix, nor any outer joins and hence no
2157 : : * PlaceHolderVars.
2158 : : */
4073 2159 [ - + ]: 3783 : Assert(root->append_rel_list == NIL);
2160 [ - + ]: 3783 : Assert(root->join_info_list == NIL);
2161 [ - + ]: 3783 : Assert(root->placeholder_list == NIL);
2162 : :
2163 : : /*
2164 : : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
2165 : : * rtable entry in the current query level, so this is easy.
2166 : : */
2654 2167 [ - + ]: 3783 : Assert(list_length(parse->rtable) == 1);
2168 : :
2169 : : /* Create suitable RTE */
2170 : 3783 : rte = makeNode(RangeTblEntry);
2171 : 3783 : rte->rtekind = RTE_RESULT;
2172 : 3783 : rte->eref = makeAlias("*RESULT*", NIL);
2173 : :
2174 : : /* Replace rangetable */
2175 : 3783 : parse->rtable = list_make1(rte);
2176 : :
2177 : : /* We could manufacture a new RangeTblRef, but the one we have is fine */
2178 [ - + ]: 3783 : Assert(varno == 1);
2179 : :
2180 : 3783 : return jtnode;
2181 : : }
2182 : :
2183 : : /*
2184 : : * is_simple_values
2185 : : * Check a VALUES RTE in the range table to see if it's simple enough
2186 : : * to pull up into the parent query.
2187 : : *
2188 : : * rte is the RTE_VALUES RangeTblEntry to check.
2189 : : */
2190 : : static bool
2191 : 10652 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
2192 : : {
4073 2193 [ - + ]: 10652 : Assert(rte->rtekind == RTE_VALUES);
2194 : :
2195 : : /*
2196 : : * There must be exactly one VALUES list, else it's not semantically
2197 : : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
2198 : : * a unique set of expressions to substitute into the parent query.
2199 : : */
2200 [ + + ]: 10652 : if (list_length(rte->values_lists) != 1)
2201 : 6869 : return false;
2202 : :
2203 : : /*
2204 : : * Because VALUES can't appear under an outer join (or at least, we won't
2205 : : * try to pull it up if it does), we need not worry about LATERAL, nor
2206 : : * about validity of PHVs for the VALUES' outputs.
2207 : : */
2208 : :
2209 : : /*
2210 : : * Don't pull up a VALUES that contains any set-returning or volatile
2211 : : * functions. The considerations here are basically identical to the
2212 : : * restrictions on a pull-able subquery's targetlist.
2213 : : */
2214 [ + - - + ]: 7566 : if (expression_returns_set((Node *) rte->values_lists) ||
2215 : 3783 : contain_volatile_functions((Node *) rte->values_lists))
4073 tgl@sss.pgh.pa.us 2216 :UBC 0 : return false;
2217 : :
2218 : : /*
2219 : : * Do not pull up a VALUES that's not the only RTE in its parent query.
2220 : : * This is actually the only case that the parser will generate at the
2221 : : * moment, and assuming this is true greatly simplifies
2222 : : * pull_up_simple_values().
2223 : : */
4073 tgl@sss.pgh.pa.us 2224 [ + - ]:CBC 3783 : if (list_length(root->parse->rtable) != 1 ||
2225 [ - + ]: 3783 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
8506 tgl@sss.pgh.pa.us 2226 :UBC 0 : return false;
2227 : :
8506 tgl@sss.pgh.pa.us 2228 :CBC 3783 : return true;
2229 : : }
2230 : :
2231 : : /*
2232 : : * pull_up_constant_function
2233 : : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
2234 : : *
2235 : : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
2236 : : * pull_up_subqueries. If its expression is just a Const, hoist that value
2237 : : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
2238 : : *
2239 : : * In principle we could pull up any immutable expression, but we don't.
2240 : : * That might result in multiple evaluations of the expression, which could
2241 : : * be costly if it's not just a Const. Also, the main value of this is
2242 : : * to let the constant participate in further const-folding, and of course
2243 : : * that won't happen for a non-Const.
2244 : : *
2245 : : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
2246 : : * RTE is below an outer join or is part of an appendrel; the extra
2247 : : * parameters show whether that's needed.
2248 : : */
2249 : : static Node *
2469 2250 : 36162 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
2251 : : RangeTblEntry *rte,
2252 : : AppendRelInfo *containing_appendrel)
2253 : : {
2254 : 36162 : Query *parse = root->parse;
2255 : : RangeTblFunction *rtf;
2256 : : TypeFuncClass functypclass;
2257 : : Oid funcrettype;
2258 : : TupleDesc tupdesc;
2259 : : pullup_replace_vars_context rvcontext;
2260 : :
2261 : : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
2262 [ + + ]: 36162 : if (rte->funcordinality)
2263 : 778 : return jtnode;
2264 : :
2265 : : /* Fail if RTE isn't a single, simple Const expr */
2266 [ + + ]: 35384 : if (list_length(rte->functions) != 1)
2267 : 57 : return jtnode;
2268 : 35327 : rtf = linitial_node(RangeTblFunction, rte->functions);
2269 [ + + ]: 35327 : if (!IsA(rtf->funcexpr, Const))
2270 : 35017 : return jtnode;
2271 : :
2272 : : /*
2273 : : * If the function's result is not a scalar, we punt. In principle we
2274 : : * could break the composite constant value apart into per-column
2275 : : * constants, but for now it seems not worth the work.
2276 : : */
2415 2277 [ + + ]: 310 : if (rtf->funccolcount != 1)
2278 : 25 : return jtnode; /* definitely composite */
2279 : :
2280 : : /* If it has a coldeflist, it certainly returns RECORD */
750 2281 [ - + ]: 285 : if (rtf->funccolnames != NIL)
750 tgl@sss.pgh.pa.us 2282 :UBC 0 : return jtnode; /* must be a one-column RECORD type */
2283 : :
2415 tgl@sss.pgh.pa.us 2284 :CBC 285 : functypclass = get_expr_result_type(rtf->funcexpr,
2285 : : &funcrettype,
2286 : : &tupdesc);
2287 [ + + ]: 285 : if (functypclass != TYPEFUNC_SCALAR)
2288 : 10 : return jtnode; /* must be a one-column composite type */
2289 : :
2290 : : /* Create context for applying pullup_replace_vars */
2469 2291 : 275 : rvcontext.root = root;
2292 : 275 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
2293 : : 1, /* resno */
2294 : : NULL, /* resname */
2295 : : false)); /* resjunk */
2296 : 275 : rvcontext.target_rte = rte;
434 rguo@postgresql.org 2297 : 275 : rvcontext.result_relation = 0;
2298 : :
2299 : : /*
2300 : : * Since this function was reduced to a Const, it doesn't contain any
2301 : : * lateral references, even if it's marked as LATERAL. This means we
2302 : : * don't need to fill relids or nullinfo.
2303 : : */
2469 tgl@sss.pgh.pa.us 2304 : 275 : rvcontext.relids = NULL;
521 2305 : 275 : rvcontext.nullinfo = NULL;
2306 : :
2469 2307 : 275 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2308 : 275 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
2309 : : /* this flag will be set below, if needed */
418 rguo@postgresql.org 2310 : 275 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2311 : : /* initialize cache array with indexes 0 .. length(tlist) */
2469 tgl@sss.pgh.pa.us 2312 : 275 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
2313 : : sizeof(Node *));
2314 : :
2315 : : /*
2316 : : * If the parent query uses grouping sets, we need a PlaceHolderVar for
2317 : : * each expression of the subquery's targetlist items. (See comments in
2318 : : * pull_up_simple_subquery().)
2319 : : */
2320 [ - + ]: 275 : if (parse->groupingSets)
418 rguo@postgresql.org 2321 :UBC 0 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
2322 : :
2323 : : /*
2324 : : * Replace all of the top query's references to the RTE's output with
2325 : : * copies of the funcexpr, being careful not to replace any of the
2326 : : * jointree structure.
2327 : : */
2469 tgl@sss.pgh.pa.us 2328 :CBC 275 : perform_pullup_replace_vars(root, &rvcontext,
2329 : : containing_appendrel);
2330 : :
2331 : : /*
2332 : : * We don't need to bother with changing PlaceHolderVars in the parent
2333 : : * query. Their references to the RT index are still good for now, and
2334 : : * will get removed later if we're able to drop the RTE_RESULT.
2335 : : */
2336 : :
2337 : : /*
2338 : : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
2339 : : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
2340 : : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
2341 : : * RTE_RESULTs to be LATERAL.
2342 : : */
2343 : 275 : rte->rtekind = RTE_RESULT;
2344 : 275 : rte->functions = NIL;
1761 2345 : 275 : rte->lateral = false;
2346 : :
2347 : : /*
2348 : : * We can reuse the RangeTblRef node.
2349 : : */
2469 2350 : 275 : return jtnode;
2351 : : }
2352 : :
2353 : : /*
2354 : : * is_simple_union_all
2355 : : * Check a subquery to see if it's a simple UNION ALL.
2356 : : *
2357 : : * We require all the setops to be UNION ALL (no mixing) and there can't be
2358 : : * any datatype coercions involved, ie, all the leaf queries must emit the
2359 : : * same datatypes.
2360 : : */
2361 : : static bool
7396 2362 : 21629 : is_simple_union_all(Query *subquery)
2363 : : {
2364 : : SetOperationStmt *topop;
2365 : :
2366 : : /* Let's just make sure it's a valid subselect ... */
2367 [ + - ]: 21629 : if (!IsA(subquery, Query) ||
3398 2368 [ - + ]: 21629 : subquery->commandType != CMD_SELECT)
7396 tgl@sss.pgh.pa.us 2369 [ # # ]:UBC 0 : elog(ERROR, "subquery is bogus");
2370 : :
2371 : : /* Is it a set-operation query at all? */
3360 peter_e@gmx.net 2372 :CBC 21629 : topop = castNode(SetOperationStmt, subquery->setOperations);
7396 tgl@sss.pgh.pa.us 2373 [ + + ]: 21629 : if (!topop)
2374 : 16941 : return false;
2375 : :
2376 : : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
2377 [ + + ]: 4688 : if (subquery->sortClause ||
2378 [ + - ]: 4636 : subquery->limitOffset ||
2379 [ + - ]: 4636 : subquery->limitCount ||
6422 2380 [ + - ]: 4636 : subquery->rowMarks ||
2381 [ + + ]: 4636 : subquery->cteList)
7396 2382 : 158 : return false;
2383 : :
2384 : : /* Recursively check the tree of set operations */
2385 : 4530 : return is_simple_union_all_recurse((Node *) topop, subquery,
2386 : : topop->colTypes);
2387 : : }
2388 : :
2389 : : static bool
2390 : 27742 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
2391 : : {
2392 : : /* Since this function recurses, it could be driven to stack overflow. */
1230 2393 : 27742 : check_stack_depth();
2394 : :
7396 2395 [ + + ]: 27742 : if (IsA(setOp, RangeTblRef))
2396 : : {
2397 : 13953 : RangeTblRef *rtr = (RangeTblRef *) setOp;
2398 : 13953 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
2399 : 13953 : Query *subquery = rte->subquery;
2400 : :
2401 [ - + ]: 13953 : Assert(subquery != NULL);
2402 : :
2403 : : /* Leaf nodes are OK if they match the toplevel column types */
2404 : : /* We don't have to compare typmods or collations here */
2405 : 13953 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
2406 : : }
2407 [ + - ]: 13789 : else if (IsA(setOp, SetOperationStmt))
2408 : : {
2409 : 13789 : SetOperationStmt *op = (SetOperationStmt *) setOp;
2410 : :
2411 : : /* Must be UNION ALL */
2412 [ + + + + ]: 13789 : if (op->op != SETOP_UNION || !op->all)
2413 : 4195 : return false;
2414 : :
2415 : : /* Recurse to check inputs */
2416 [ + + + + ]: 18386 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
2417 : 8792 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2418 : : }
2419 : : else
2420 : : {
7396 tgl@sss.pgh.pa.us 2421 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
2422 : : (int) nodeTag(setOp));
2423 : : return false; /* keep compiler quiet */
2424 : : }
2425 : : }
2426 : :
2427 : : /*
2428 : : * is_safe_append_member
2429 : : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2430 : : * safe to pull up.
2431 : : */
2432 : : static bool
7396 tgl@sss.pgh.pa.us 2433 :CBC 15239 : is_safe_append_member(Query *subquery)
2434 : : {
2435 : : FromExpr *jtnode;
2436 : :
2437 : : /*
2438 : : * It's only safe to pull up the child if its jointree contains exactly
2439 : : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2440 : : * could be buried in several levels of FromExpr, however. Also, if the
2441 : : * child's jointree is completely empty, we can pull up because
2442 : : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2443 : : *
2444 : : * Also, the child can't have any WHERE quals because there's no place to
2445 : : * put them in an appendrel. (This is a bit annoying...) If we didn't
2446 : : * need to check this, we'd just test whether get_relids_in_jointree()
2447 : : * yields a singleton set, to be more consistent with the coding of
2448 : : * fix_append_rel_relids().
2449 : : */
2450 : 15239 : jtnode = subquery->jointree;
2654 2451 [ - + ]: 15239 : Assert(IsA(jtnode, FromExpr));
2452 : : /* Check the completely-empty case */
2453 [ + + + + ]: 15239 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2454 : 554 : return true;
2455 : : /* Check the more general case */
7396 2456 [ + + ]: 25704 : while (IsA(jtnode, FromExpr))
2457 : : {
2458 [ + + ]: 14695 : if (jtnode->quals != NULL)
2459 : 3676 : return false;
2460 [ - + ]: 11019 : if (list_length(jtnode->fromlist) != 1)
7396 tgl@sss.pgh.pa.us 2461 :UBC 0 : return false;
7396 tgl@sss.pgh.pa.us 2462 :CBC 11019 : jtnode = linitial(jtnode->fromlist);
2463 : : }
2464 [ + + ]: 11009 : if (!IsA(jtnode, RangeTblRef))
2465 : 1197 : return false;
2466 : :
2467 : 9812 : return true;
2468 : : }
2469 : :
2470 : : /*
2471 : : * jointree_contains_lateral_outer_refs
2472 : : * Check for disallowed lateral references in a jointree's quals
2473 : : *
2474 : : * If restricted is false, all level-1 Vars are allowed (but we still must
2475 : : * search the jointree, since it might contain outer joins below which there
2476 : : * will be restrictions). If restricted is true, return true when any qual
2477 : : * in the jointree contains level-1 Vars coming from outside the rels listed
2478 : : * in safe_upper_varnos.
2479 : : */
2480 : : static bool
1930 2481 : 9996 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2482 : : bool restricted,
2483 : : Relids safe_upper_varnos)
2484 : : {
4642 2485 [ - + ]: 9996 : if (jtnode == NULL)
4642 tgl@sss.pgh.pa.us 2486 :UBC 0 : return false;
4642 tgl@sss.pgh.pa.us 2487 [ + + ]:CBC 9996 : if (IsA(jtnode, RangeTblRef))
2488 : 6293 : return false;
2489 [ + + ]: 3703 : else if (IsA(jtnode, FromExpr))
2490 : : {
2491 : 3444 : FromExpr *f = (FromExpr *) jtnode;
2492 : : ListCell *l;
2493 : :
2494 : : /* First, recurse to check child joins */
2495 [ + + + + : 9498 : foreach(l, f->fromlist)
+ + ]
2496 : : {
1930 2497 [ + + ]: 6074 : if (jointree_contains_lateral_outer_refs(root,
2498 : 6074 : lfirst(l),
2499 : : restricted,
2500 : : safe_upper_varnos))
4642 2501 : 20 : return true;
2502 : : }
2503 : :
2504 : : /* Then check the top-level quals */
2505 [ + + ]: 3424 : if (restricted &&
1930 2506 [ - + ]: 1050 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2507 : : safe_upper_varnos))
4642 tgl@sss.pgh.pa.us 2508 :UBC 0 : return true;
2509 : : }
4642 tgl@sss.pgh.pa.us 2510 [ + - ]:CBC 259 : else if (IsA(jtnode, JoinExpr))
2511 : : {
2512 : 259 : JoinExpr *j = (JoinExpr *) jtnode;
2513 : :
2514 : : /*
2515 : : * If this is an outer join, we mustn't allow any upper lateral
2516 : : * references in or below it.
2517 : : */
2518 [ + + ]: 259 : if (j->jointype != JOIN_INNER)
2519 : : {
2520 : 129 : restricted = true;
2521 : 129 : safe_upper_varnos = NULL;
2522 : : }
2523 : :
2524 : : /* Check the child joins */
1930 2525 [ - + ]: 259 : if (jointree_contains_lateral_outer_refs(root,
2526 : : j->larg,
2527 : : restricted,
2528 : : safe_upper_varnos))
4642 tgl@sss.pgh.pa.us 2529 :UBC 0 : return true;
1930 tgl@sss.pgh.pa.us 2530 [ - + ]:CBC 259 : if (jointree_contains_lateral_outer_refs(root,
2531 : : j->rarg,
2532 : : restricted,
2533 : : safe_upper_varnos))
4642 tgl@sss.pgh.pa.us 2534 :UBC 0 : return true;
2535 : :
2536 : : /* Check the JOIN's qual clauses */
4642 tgl@sss.pgh.pa.us 2537 [ + + ]:CBC 259 : if (restricted &&
1930 2538 [ + + ]: 239 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2539 : : safe_upper_varnos))
4642 2540 : 20 : return true;
2541 : : }
2542 : : else
4642 tgl@sss.pgh.pa.us 2543 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
2544 : : (int) nodeTag(jtnode));
4642 tgl@sss.pgh.pa.us 2545 :CBC 3663 : return false;
2546 : : }
2547 : :
2548 : : /*
2549 : : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2550 : : *
2551 : : * Caller has already filled *rvcontext with data describing what to
2552 : : * substitute for Vars referencing the target subquery. In addition
2553 : : * we need the identity of the containing appendrel if any.
2554 : : */
2555 : : static void
2469 2556 : 33485 : perform_pullup_replace_vars(PlannerInfo *root,
2557 : : pullup_replace_vars_context *rvcontext,
2558 : : AppendRelInfo *containing_appendrel)
2559 : : {
2560 : 33485 : Query *parse = root->parse;
2561 : : ListCell *lc;
2562 : :
2563 : : /*
2564 : : * If we are considering an appendrel child subquery (that is, a UNION ALL
2565 : : * member query that we're pulling up), then the only part of the upper
2566 : : * query that could reference the child yet is the translated_vars list of
2567 : : * the associated AppendRelInfo. Furthermore, we do not want to force use
2568 : : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2569 : : */
1230 2570 [ + + ]: 33485 : if (containing_appendrel)
2571 : : {
418 rguo@postgresql.org 2572 : 5121 : ReplaceWrapOption save_wrap_option = rvcontext->wrap_option;
2573 : :
2574 : 5121 : rvcontext->wrap_option = REPLACE_WRAP_NONE;
1230 tgl@sss.pgh.pa.us 2575 : 5121 : containing_appendrel->translated_vars = (List *)
2576 : 5121 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2577 : : rvcontext);
418 rguo@postgresql.org 2578 : 5121 : rvcontext->wrap_option = save_wrap_option;
1230 tgl@sss.pgh.pa.us 2579 : 5121 : return;
2580 : : }
2581 : :
2582 : : /*
2583 : : * Replace all of the top query's references to the subquery's outputs
2584 : : * with copies of the adjusted subtlist items, being careful not to
2585 : : * replace any of the jointree structure. (This'd be a lot cleaner if we
2586 : : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2587 : : * returningList, and havingQual, since those are certainly above any
2588 : : * outer join. replace_vars_in_jointree tracks its location in the
2589 : : * jointree and uses PHVs or not appropriately.
2590 : : */
2469 2591 : 28364 : parse->targetList = (List *)
2592 : 28364 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2593 : 28364 : parse->returningList = (List *)
2594 : 28364 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2595 : :
2596 [ + + ]: 28364 : if (parse->onConflict)
2597 : : {
2598 : 34 : parse->onConflict->onConflictSet = (List *)
2599 : 17 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2600 : : rvcontext);
2601 : 17 : parse->onConflict->onConflictWhere =
2602 : 17 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2603 : : rvcontext);
2604 : :
2605 : : /*
2606 : : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2607 : : * can't contain any references to a subquery.
2608 : : */
2609 : : }
1499 alvherre@alvh.no-ip. 2610 [ + + ]: 28364 : if (parse->mergeActionList)
2611 : : {
2612 [ + - + + : 2348 : foreach(lc, parse->mergeActionList)
+ + ]
2613 : : {
2614 : 1389 : MergeAction *action = lfirst(lc);
2615 : :
2616 : 1389 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2617 : 1389 : action->targetList = (List *)
2618 : 1389 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2619 : : }
2620 : : }
766 dean.a.rasheed@gmail 2621 : 28364 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2622 : : rvcontext);
1191 tgl@sss.pgh.pa.us 2623 : 28364 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2469 2624 [ - + ]: 28364 : Assert(parse->setOperations == NULL);
2625 : 28364 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2626 : :
2627 : : /*
2628 : : * Replace references in the translated_vars lists of appendrels.
2629 : : */
2630 [ + + + + : 28424 : foreach(lc, root->append_rel_list)
+ + ]
2631 : : {
2632 : 60 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2633 : :
2634 : 60 : appinfo->translated_vars = (List *)
2635 : 60 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2636 : : }
2637 : :
2638 : : /*
2639 : : * Replace references in the joinaliasvars lists of join RTEs and the
2640 : : * groupexprs list of group RTE.
2641 : : */
2642 [ + - + + : 79221 : foreach(lc, parse->rtable)
+ + ]
2643 : : {
2644 : 50857 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2645 : :
2646 [ + + ]: 50857 : if (otherrte->rtekind == RTE_JOIN)
2647 : 5438 : otherrte->joinaliasvars = (List *)
2648 : 5438 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2649 : : rvcontext);
602 rguo@postgresql.org 2650 [ + + ]: 45419 : else if (otherrte->rtekind == RTE_GROUP)
2651 : 723 : otherrte->groupexprs = (List *)
2652 : 723 : pullup_replace_vars((Node *) otherrte->groupexprs,
2653 : : rvcontext);
2654 : : }
2655 : : }
2656 : :
2657 : : /*
2658 : : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2659 : : * every expression in the jointree, without changing the jointree structure
2660 : : * itself. Ugly, but there's no other way...
2661 : : */
2662 : : static void
6089 tgl@sss.pgh.pa.us 2663 : 74307 : replace_vars_in_jointree(Node *jtnode,
2664 : : pullup_replace_vars_context *context)
2665 : : {
8506 2666 [ - + ]: 74307 : if (jtnode == NULL)
8506 tgl@sss.pgh.pa.us 2667 :UBC 0 : return;
8506 tgl@sss.pgh.pa.us 2668 [ + + ]:CBC 74307 : if (IsA(jtnode, RangeTblRef))
2669 : : {
2670 : : /*
2671 : : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2672 : : * same subquery we're pulling up), it might contain references to the
2673 : : * target subquery, which we must replace. We drive this from the
2674 : : * jointree scan, rather than a scan of the rtable, so that we can
2675 : : * avoid processing no-longer-referenced RTEs.
2676 : : */
5008 2677 : 37296 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2678 : :
2679 [ + + ]: 37296 : if (varno != context->varno) /* ignore target subquery itself */
2680 : : {
2681 : 8932 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2682 : :
2683 [ - + ]: 8932 : Assert(rte != context->target_rte);
2684 [ + + ]: 8932 : if (rte->lateral)
2685 : : {
2686 [ - + + + : 752 : switch (rte->rtekind)
- - - - ]
2687 : : {
3937 tgl@sss.pgh.pa.us 2688 :UBC 0 : case RTE_RELATION:
2689 : : /* shouldn't be marked LATERAL unless tablesample */
2690 [ # # ]: 0 : Assert(rte->tablesample);
2691 : 0 : rte->tablesample = (TableSampleClause *)
2692 : 0 : pullup_replace_vars((Node *) rte->tablesample,
2693 : : context);
2694 : 0 : break;
5008 tgl@sss.pgh.pa.us 2695 :CBC 372 : case RTE_SUBQUERY:
2696 : 372 : rte->subquery =
2697 : 372 : pullup_replace_vars_subquery(rte->subquery,
2698 : : context);
2699 : 372 : break;
2700 : 290 : case RTE_FUNCTION:
4548 2701 : 290 : rte->functions = (List *)
2702 : 290 : pullup_replace_vars((Node *) rte->functions,
2703 : : context);
5008 2704 : 290 : break;
3345 alvherre@alvh.no-ip. 2705 : 90 : case RTE_TABLEFUNC:
2706 : 90 : rte->tablefunc = (TableFunc *)
2707 : 90 : pullup_replace_vars((Node *) rte->tablefunc,
2708 : : context);
2709 : 90 : break;
5008 tgl@sss.pgh.pa.us 2710 :UBC 0 : case RTE_VALUES:
2711 : 0 : rte->values_lists = (List *)
2712 : 0 : pullup_replace_vars((Node *) rte->values_lists,
2713 : : context);
2714 : 0 : break;
2715 : 0 : case RTE_JOIN:
2716 : : case RTE_CTE:
2717 : : case RTE_NAMEDTUPLESTORE:
2718 : : case RTE_RESULT:
2719 : : case RTE_GROUP:
2720 : : /* these shouldn't be marked LATERAL */
2721 : 0 : Assert(false);
2722 : : break;
50 peter@eisentraut.org 2723 :UNC 0 : case RTE_GRAPH_TABLE:
2724 : : /* shouldn't happen here */
2725 : 0 : Assert(false);
2726 : : break;
2727 : : }
2728 : : }
2729 : : }
2730 : : }
8506 tgl@sss.pgh.pa.us 2731 [ + + ]:CBC 37011 : else if (IsA(jtnode, FromExpr))
2732 : : {
2733 : 30581 : FromExpr *f = (FromExpr *) jtnode;
2734 : : ListCell *l;
2735 : :
2736 [ + - + + : 63664 : foreach(l, f->fromlist)
+ + ]
1191 2737 : 33083 : replace_vars_in_jointree(lfirst(l), context);
6089 2738 : 30581 : f->quals = pullup_replace_vars(f->quals, context);
2739 : : }
8506 2740 [ + - ]: 6430 : else if (IsA(jtnode, JoinExpr))
2741 : : {
2742 : 6430 : JoinExpr *j = (JoinExpr *) jtnode;
418 rguo@postgresql.org 2743 : 6430 : ReplaceWrapOption save_wrap_option = context->wrap_option;
2744 : :
1191 tgl@sss.pgh.pa.us 2745 : 6430 : replace_vars_in_jointree(j->larg, context);
2746 : 6430 : replace_vars_in_jointree(j->rarg, context);
2747 : :
2748 : : /*
2749 : : * Use PHVs within the join quals of a full join for variable-free
2750 : : * expressions. Otherwise, we cannot identify which side of the join
2751 : : * a pulled-up variable-free expression came from, which can lead to
2752 : : * failure to make a plan at all because none of the quals appear to
2753 : : * be mergeable or hashable conditions.
2754 : : */
2760 2755 [ + + ]: 6430 : if (j->jointype == JOIN_FULL)
418 rguo@postgresql.org 2756 : 515 : context->wrap_option = REPLACE_WRAP_VARFREE;
2757 : :
6089 tgl@sss.pgh.pa.us 2758 : 6430 : j->quals = pullup_replace_vars(j->quals, context);
2759 : :
418 rguo@postgresql.org 2760 : 6430 : context->wrap_option = save_wrap_option;
2761 : : }
2762 : : else
8320 tgl@sss.pgh.pa.us 2763 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
2764 : : (int) nodeTag(jtnode));
2765 : : }
2766 : :
2767 : : /*
2768 : : * Apply pullup variable replacement throughout an expression tree
2769 : : *
2770 : : * Returns a modified copy of the tree, so this can't be used where we
2771 : : * need to do in-place replacement.
2772 : : */
2773 : : static Node *
6089 tgl@sss.pgh.pa.us 2774 :CBC 166101 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2775 : : {
2776 : 166101 : return replace_rte_variables(expr,
2777 : : context->varno, 0,
2778 : : pullup_replace_vars_callback,
2779 : : context,
2780 : : context->outer_hasSubLinks);
2781 : : }
2782 : :
2783 : : static Node *
47 peter@eisentraut.org 2784 :GNC 97068 : pullup_replace_vars_callback(const Var *var,
2785 : : replace_rte_variables_context *context)
2786 : : {
6089 tgl@sss.pgh.pa.us 2787 :CBC 97068 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2788 : 97068 : int varattno = var->varattno;
2789 : : bool need_phv;
2790 : : Node *newnode;
2791 : :
2792 : : /* System columns are not replaced. */
434 rguo@postgresql.org 2793 [ + + ]: 97068 : if (varattno < InvalidAttrNumber)
2794 : 35 : return (Node *) copyObject(var);
2795 : :
2796 : : /*
2797 : : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2798 : : * varnullingrels (unless we find below that the replacement expression is
2799 : : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2800 : : * also need one if the caller has instructed us that certain expression
2801 : : * replacements need to be wrapped for identification purposes.
2802 : : */
418 2803 [ + + ]: 184443 : need_phv = (var->varnullingrels != NULL) ||
2804 [ + + ]: 87410 : (rcon->wrap_option != REPLACE_WRAP_NONE);
2805 : :
2806 : : /*
2807 : : * If PlaceHolderVars are needed, we cache the modified expressions in
2808 : : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2809 : : * within this function, but to avoid generating identical PHVs with
2810 : : * different IDs. That would result in duplicate evaluations at runtime,
2811 : : * and possibly prevent optimizations that rely on recognizing different
2812 : : * references to the same subquery output as being equal(). So it's worth
2813 : : * a bit of extra effort to avoid it.
2814 : : *
2815 : : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2816 : : * copy them and adjust those values for this reference site below.
2817 : : */
1191 tgl@sss.pgh.pa.us 2818 [ + + + - ]: 97033 : if (need_phv &&
6089 2819 [ + - ]: 11551 : varattno >= InvalidAttrNumber &&
2820 : 11551 : varattno <= list_length(rcon->targetlist) &&
2821 [ + + ]: 11551 : rcon->rv_cache[varattno] != NULL)
2822 : : {
2823 : : /* Just copy the entry and fall through to adjust phlevelsup etc */
2824 : 2473 : newnode = copyObject(rcon->rv_cache[varattno]);
2825 : : }
2826 : : else
2827 : : {
2828 : : /*
2829 : : * Generate the replacement expression. This takes care of expanding
2830 : : * wholerow references and dealing with non-default varreturningtype.
2831 : : */
434 rguo@postgresql.org 2832 : 94560 : newnode = ReplaceVarFromTargetList(var,
2833 : : rcon->target_rte,
2834 : : rcon->targetlist,
2835 : : rcon->result_relation,
2836 : : REPLACEVARS_REPORT_ERROR,
2837 : : 0);
2838 : :
2839 : : /* Insert PlaceHolderVar if needed */
1191 tgl@sss.pgh.pa.us 2840 [ + + ]: 94560 : if (need_phv)
2841 : : {
2842 : : bool wrap;
2843 : :
418 rguo@postgresql.org 2844 [ + + ]: 9078 : if (rcon->wrap_option == REPLACE_WRAP_ALL)
2845 : : {
2846 : : /* Caller told us to wrap all expressions in a PlaceHolderVar */
2847 : 892 : wrap = true;
2848 : : }
2849 [ + + ]: 8186 : else if (varattno == InvalidAttrNumber)
2850 : : {
2851 : : /*
2852 : : * Insert PlaceHolderVar for whole-tuple reference. Notice
2853 : : * that we are wrapping one PlaceHolderVar around the whole
2854 : : * RowExpr, rather than putting one around each element of the
2855 : : * row. This is because we need the expression to yield NULL,
2856 : : * not ROW(NULL,NULL,...) when it is forced to null by an
2857 : : * outer join.
2858 : : */
434 2859 : 55 : wrap = true;
2860 : : }
2861 [ + - + + ]: 8131 : else if (newnode && IsA(newnode, Var) &&
2862 [ + + ]: 6508 : ((Var *) newnode)->varlevelsup == 0)
2863 : : {
2864 : : /*
2865 : : * Simple Vars always escape being wrapped, unless they are
2866 : : * lateral references to something outside the subquery being
2867 : : * pulled up and the referenced rel is not under the same
2868 : : * lowest nulling outer join.
2869 : : */
512 2870 : 6496 : wrap = false;
4644 tgl@sss.pgh.pa.us 2871 [ + + ]: 6496 : if (rcon->target_rte->lateral &&
2872 [ + + ]: 1175 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2873 : : {
512 rguo@postgresql.org 2874 : 110 : nullingrel_info *nullinfo = rcon->nullinfo;
2875 : 110 : int lvarno = ((Var *) newnode)->varno;
2876 : :
2877 [ + - - + ]: 110 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2878 [ + + ]: 110 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2879 : 110 : nullinfo->nullingrels[lvarno]))
2880 : 90 : wrap = true;
2881 : : }
2882 : : }
5383 tgl@sss.pgh.pa.us 2883 [ + - + + ]: 1635 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2884 [ + - ]: 150 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2885 : : {
2886 : : /* The same rules apply for a PlaceHolderVar */
512 rguo@postgresql.org 2887 : 150 : wrap = false;
845 tgl@sss.pgh.pa.us 2888 [ + + ]: 150 : if (rcon->target_rte->lateral &&
2889 [ + - ]: 40 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2890 : 40 : rcon->relids))
2891 : : {
512 rguo@postgresql.org 2892 : 40 : nullingrel_info *nullinfo = rcon->nullinfo;
2893 : 40 : Relids lvarnos = ((PlaceHolderVar *) newnode)->phrels;
2894 : : int lvarno;
2895 : :
2896 : 40 : lvarno = -1;
2897 [ + + ]: 60 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2898 : : {
2899 [ + - - + ]: 40 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2900 [ + + ]: 40 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2901 : 40 : nullinfo->nullingrels[lvarno]))
2902 : : {
2903 : 20 : wrap = true;
2904 : 20 : break;
2905 : : }
2906 : : }
2907 : : }
2908 : : }
2909 : : else
2910 : : {
2911 : : /*
2912 : : * If the node contains Var(s) or PlaceHolderVar(s) of the
2913 : : * subquery being pulled up, or of rels that are under the
2914 : : * same lowest nulling outer join as the subquery, and does
2915 : : * not contain any non-strict constructs, then instead of
2916 : : * adding a PHV on top we can add the required nullingrels to
2917 : : * those Vars/PHVs. (This is fundamentally a generalization
2918 : : * of the above cases for bare Vars and PHVs.)
2919 : : *
2920 : : * This test is somewhat expensive, but it avoids pessimizing
2921 : : * the plan in cases where the nullingrels get removed again
2922 : : * later by outer join reduction.
2923 : : *
2924 : : * Note that we don't force wrapping of expressions containing
2925 : : * lateral references, so long as they also contain Vars/PHVs
2926 : : * of the subquery, or of rels that are under the same lowest
2927 : : * nulling outer join as the subquery. This is okay because
2928 : : * of the restriction to strict constructs: if those Vars/PHVs
2929 : : * have been forced to NULL by an outer join then the end
2930 : : * result of the expression will be NULL too, regardless of
2931 : : * the lateral references. So it's not necessary to force the
2932 : : * expression to be evaluated below the outer join. This can
2933 : : * be a very valuable optimization, because it may allow us to
2934 : : * avoid using a nested loop to pass the lateral reference
2935 : : * down.
2936 : : *
2937 : : * This analysis could be tighter: in particular, a non-strict
2938 : : * construct hidden within a lower-level PlaceHolderVar is not
2939 : : * reason to add another PHV. But for now it doesn't seem
2940 : : * worth the code to be more exact. This is also why it's
2941 : : * preferable to handle bare PHVs in the above branch, rather
2942 : : * than this branch. We also prefer to handle bare Vars in a
2943 : : * separate branch, as it's cheaper this way and parallels the
2944 : : * handling of PHVs.
2945 : : *
2946 : : * For a LATERAL subquery, we have to check the actual var
2947 : : * membership of the node, but if it's non-lateral then any
2948 : : * level-zero var must belong to the subquery.
2949 : : */
504 2950 : 1485 : bool contain_nullable_vars = false;
2951 : :
2952 [ + + ]: 1485 : if (!rcon->target_rte->lateral)
2953 : : {
2954 [ + + ]: 1295 : if (contain_vars_of_level(newnode, 0))
2955 : 443 : contain_nullable_vars = true;
2956 : : }
2957 : : else
2958 : : {
2959 : : Relids all_varnos;
2960 : :
2961 : 190 : all_varnos = pull_varnos(rcon->root, newnode);
2962 [ + + ]: 190 : if (bms_overlap(all_varnos, rcon->relids))
2963 : 110 : contain_nullable_vars = true;
2964 : : else
2965 : : {
2966 : 80 : nullingrel_info *nullinfo = rcon->nullinfo;
2967 : : int varno;
2968 : :
2969 : 80 : varno = -1;
2970 [ + + ]: 150 : while ((varno = bms_next_member(all_varnos, varno)) >= 0)
2971 : : {
2972 [ + - - + ]: 90 : Assert(varno > 0 && varno <= nullinfo->rtlength);
2973 [ + + ]: 90 : if (bms_is_subset(nullinfo->nullingrels[rcon->varno],
2974 : 90 : nullinfo->nullingrels[varno]))
2975 : : {
2976 : 20 : contain_nullable_vars = true;
2977 : 20 : break;
2978 : : }
2979 : : }
2980 : : }
2981 : : }
2982 : :
2983 [ + + ]: 1485 : if (contain_nullable_vars &&
613 tgl@sss.pgh.pa.us 2984 [ + + ]: 573 : !contain_nonstrict_functions(newnode))
2985 : : {
2986 : : /* No wrap needed */
2987 : 240 : wrap = false;
2988 : : }
2989 : : else
2990 : : {
2991 : : /* Else wrap it in a PlaceHolderVar */
2992 : 1245 : wrap = true;
2993 : : }
2994 : : }
2995 : :
6089 2996 [ + + ]: 9078 : if (wrap)
2997 : : {
2998 : : newnode = (Node *)
2999 : 2302 : make_placeholder_expr(rcon->root,
3000 : : (Expr *) newnode,
3001 : : bms_make_singleton(rcon->varno));
3002 : :
3003 : : /*
3004 : : * Cache it if possible (ie, if the attno is in range, which
3005 : : * it probably always should be).
3006 : : */
434 rguo@postgresql.org 3007 [ + - + - ]: 4604 : if (varattno >= InvalidAttrNumber &&
1191 tgl@sss.pgh.pa.us 3008 : 2302 : varattno <= list_length(rcon->targetlist))
3009 : 2302 : rcon->rv_cache[varattno] = copyObject(newnode);
3010 : : }
3011 : : }
3012 : : }
3013 : :
3014 : : /* Propagate any varnullingrels into the replacement expression */
3015 [ + + ]: 97033 : if (var->varnullingrels != NULL)
3016 : : {
3017 [ + + ]: 9623 : if (IsA(newnode, Var))
3018 : : {
3019 : 6027 : Var *newvar = (Var *) newnode;
3020 : :
613 3021 [ - + ]: 6027 : Assert(newvar->varlevelsup == 0);
1191 3022 : 6027 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
3023 : 6027 : var->varnullingrels);
3024 : : }
3025 [ + + ]: 3596 : else if (IsA(newnode, PlaceHolderVar))
3026 : : {
3027 : 3356 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
3028 : :
613 3029 [ - + ]: 3356 : Assert(newphv->phlevelsup == 0);
1191 3030 : 3356 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
3031 : 3356 : var->varnullingrels);
3032 : : }
3033 : : else
3034 : : {
3035 : : /*
3036 : : * There should be Vars/PHVs within the expression that we can
3037 : : * modify. Vars/PHVs of the subquery should have the full
3038 : : * var->varnullingrels added to them, but if there are lateral
3039 : : * references within the expression, those must be marked with
3040 : : * only the nullingrels that potentially apply to them. (This
3041 : : * corresponds to the fact that the expression will now be
3042 : : * evaluated at the join level of the Var that we are replacing:
3043 : : * the lateral references may have bubbled up through fewer outer
3044 : : * joins than the subquery's Vars have. Per the discussion above,
3045 : : * we'll still get the right answers.) That relid set could be
3046 : : * different for different lateral relations, so we have to do
3047 : : * this work for each one.
3048 : : *
3049 : : * (Currently, the restrictions in is_simple_subquery() mean that
3050 : : * at most we have to remove the lowest outer join's relid from
3051 : : * the nullingrels of a lateral reference. However, we might
3052 : : * relax those restrictions someday, so let's do this right.)
3053 : : */
521 3054 [ + + ]: 240 : if (rcon->target_rte->lateral)
3055 : : {
3056 : 70 : nullingrel_info *nullinfo = rcon->nullinfo;
3057 : : Relids lvarnos;
3058 : : int lvarno;
3059 : :
3060 : : /*
3061 : : * Identify lateral varnos used within newnode. We must do
3062 : : * this before injecting var->varnullingrels into the tree.
3063 : : */
3064 : 70 : lvarnos = pull_varnos(rcon->root, newnode);
3065 : 70 : lvarnos = bms_del_members(lvarnos, rcon->relids);
3066 : : /* For each one, add relevant nullingrels if any */
3067 : 70 : lvarno = -1;
3068 [ + + ]: 140 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
3069 : : {
3070 : : Relids lnullingrels;
3071 : :
3072 [ + - - + ]: 70 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
3073 : 70 : lnullingrels = bms_intersect(var->varnullingrels,
3074 : 70 : nullinfo->nullingrels[lvarno]);
3075 [ + + ]: 70 : if (!bms_is_empty(lnullingrels))
3076 : 40 : newnode = add_nulling_relids(newnode,
3077 : 40 : bms_make_singleton(lvarno),
3078 : : lnullingrels);
3079 : : }
3080 : : }
3081 : :
3082 : : /* Finally, deal with Vars/PHVs of the subquery itself */
613 3083 : 240 : newnode = add_nulling_relids(newnode,
523 3084 : 240 : rcon->relids,
613 3085 : 240 : var->varnullingrels);
3086 : : /* Assert we did put the varnullingrels into the expression */
3087 [ - + ]: 240 : Assert(bms_is_subset(var->varnullingrels,
3088 : : pull_varnos(rcon->root, newnode)));
3089 : : }
3090 : : }
3091 : :
3092 : : /* Must adjust varlevelsup if replaced Var is within a subquery */
3093 [ + + ]: 97033 : if (var->varlevelsup > 0)
3094 : 891 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
3095 : :
6089 3096 : 97033 : return newnode;
3097 : : }
3098 : :
3099 : : /*
3100 : : * Apply pullup variable replacement to a subquery
3101 : : *
3102 : : * This needs to be different from pullup_replace_vars() because
3103 : : * replace_rte_variables will think that it shouldn't increment sublevels_up
3104 : : * before entering the Query; so we need to call it with sublevels_up == 1.
3105 : : */
3106 : : static Query *
5008 3107 : 372 : pullup_replace_vars_subquery(Query *query,
3108 : : pullup_replace_vars_context *context)
3109 : : {
3110 [ - + ]: 372 : Assert(IsA(query, Query));
3111 : 372 : return (Query *) replace_rte_variables((Node *) query,
3112 : : context->varno, 1,
3113 : : pullup_replace_vars_callback,
3114 : : context,
3115 : : NULL);
3116 : : }
3117 : :
3118 : :
3119 : : /*
3120 : : * flatten_simple_union_all
3121 : : * Try to optimize top-level UNION ALL structure into an appendrel
3122 : : *
3123 : : * If a query's setOperations tree consists entirely of simple UNION ALL
3124 : : * operations, flatten it into an append relation, which we can process more
3125 : : * intelligently than the general setops case. Otherwise, do nothing.
3126 : : *
3127 : : * In most cases, this can succeed only for a top-level query, because for a
3128 : : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
3129 : : * already have flattened the UNION via pull_up_simple_union_all. But there
3130 : : * are a few cases we can support here but not in that code path, for example
3131 : : * when the subquery also contains ORDER BY.
3132 : : */
3133 : : void
5657 3134 : 5520 : flatten_simple_union_all(PlannerInfo *root)
3135 : : {
3136 : 5520 : Query *parse = root->parse;
3137 : : SetOperationStmt *topop;
3138 : : Node *leftmostjtnode;
3139 : : int leftmostRTI;
3140 : : RangeTblEntry *leftmostRTE;
3141 : : int childRTI;
3142 : : RangeTblEntry *childRTE;
3143 : : RangeTblRef *rtr;
3144 : :
3145 : : /* Shouldn't be called unless query has setops */
3360 peter_e@gmx.net 3146 : 5520 : topop = castNode(SetOperationStmt, parse->setOperations);
3147 [ - + ]: 5520 : Assert(topop);
3148 : :
3149 : : /* Can't optimize away a recursive UNION */
5657 tgl@sss.pgh.pa.us 3150 [ + + ]: 5520 : if (root->hasRecursion)
3151 : 694 : return;
3152 : :
3153 : : /*
3154 : : * Recursively check the tree of set operations. If not all UNION ALL
3155 : : * with identical column types, punt.
3156 : : */
3157 [ + + ]: 4826 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
3158 : 4280 : return;
3159 : :
3160 : : /*
3161 : : * Locate the leftmost leaf query in the setops tree. The upper query's
3162 : : * Vars all refer to this RTE (see transformSetOperationStmt).
3163 : : */
3164 : 546 : leftmostjtnode = topop->larg;
3165 [ + - + + ]: 776 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
3166 : 230 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
3167 [ + - - + ]: 546 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
3168 : 546 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
3169 : 546 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
3170 [ - + ]: 546 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
3171 : :
3172 : : /*
3173 : : * Make a copy of the leftmost RTE and add it to the rtable. This copy
3174 : : * will represent the leftmost leaf query in its capacity as a member of
3175 : : * the appendrel. The original will represent the appendrel as a whole.
3176 : : * (We must do things this way because the upper query's Vars have to be
3177 : : * seen as referring to the whole appendrel.)
3178 : : */
3179 : 546 : childRTE = copyObject(leftmostRTE);
3180 : 546 : parse->rtable = lappend(parse->rtable, childRTE);
3181 : 546 : childRTI = list_length(parse->rtable);
3182 : :
3183 : : /* Modify the setops tree to reference the child copy */
3184 : 546 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
3185 : :
3186 : : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
3187 : 546 : leftmostRTE->inh = true;
3188 : :
3189 : : /*
3190 : : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
3191 : : * Query of a setops tree should have had an empty FromClause initially.
3192 : : */
3193 : 546 : rtr = makeNode(RangeTblRef);
3194 : 546 : rtr->rtindex = leftmostRTI;
3195 [ - + ]: 546 : Assert(parse->jointree->fromlist == NIL);
3196 : 546 : parse->jointree->fromlist = list_make1(rtr);
3197 : :
3198 : : /*
3199 : : * Now pretend the query has no setops. We must do this before trying to
3200 : : * do subquery pullup, because of Assert in pull_up_simple_subquery.
3201 : : */
3202 : 546 : parse->setOperations = NULL;
3203 : :
3204 : : /*
3205 : : * Build AppendRelInfo information, and apply pull_up_subqueries to the
3206 : : * leaf queries of the UNION ALL. (We must do that now because they
3207 : : * weren't previously referenced by the jointree, and so were missed by
3208 : : * the main invocation of pull_up_subqueries.)
3209 : : */
3210 : 546 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
3211 : : }
3212 : :
3213 : :
3214 : : /*
3215 : : * reduce_outer_joins
3216 : : * Attempt to reduce outer joins to plain inner joins.
3217 : : *
3218 : : * The idea here is that given a query like
3219 : : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
3220 : : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
3221 : : * is strict. The strict operator will always return NULL, causing the outer
3222 : : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
3223 : : * columns. Therefore, there's no need for the join to produce null-extended
3224 : : * rows in the first place --- which makes it a plain join not an outer join.
3225 : : * (This scenario may not be very likely in a query written out by hand, but
3226 : : * it's reasonably likely when pushing quals down into complex views.)
3227 : : *
3228 : : * More generally, an outer join can be reduced in strength if there is a
3229 : : * strict qual above it in the qual tree that constrains a Var from the
3230 : : * nullable side of the join to be non-null. (For FULL joins this applies
3231 : : * to each side separately.)
3232 : : *
3233 : : * Another transformation we apply here is to recognize cases like
3234 : : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.z IS NULL;
3235 : : * If we can prove that b.z must be non-null for any matching row, either
3236 : : * because the join clause is strict for b.z and b.z happens to be the join
3237 : : * key b.y, or because b.z is defined NOT NULL by table constraints and is
3238 : : * not nullable due to lower-level outer joins, then only null-extended rows
3239 : : * could pass the upper WHERE, and we can conclude that what the query is
3240 : : * really specifying is an anti-semijoin. We change the join type from
3241 : : * JOIN_LEFT to JOIN_ANTI. The IS NULL clause then becomes redundant, and
3242 : : * must be removed to prevent bogus selectivity calculations, but we leave
3243 : : * it to distribute_qual_to_rels to get rid of such clauses.
3244 : : *
3245 : : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
3246 : : * JOIN_LEFT. This saves some code here and in some later planner routines;
3247 : : * the main benefit is to reduce the number of jointypes that can appear in
3248 : : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
3249 : : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
3250 : : *
3251 : : * To ease recognition of strict qual clauses, we require this routine to be
3252 : : * run after expression preprocessing (i.e., qual canonicalization and JOIN
3253 : : * alias-var expansion).
3254 : : */
3255 : : void
7639 3256 : 25946 : reduce_outer_joins(PlannerInfo *root)
3257 : : {
3258 : : reduce_outer_joins_pass1_state *state1;
3259 : : reduce_outer_joins_pass2_state state2;
3260 : : ListCell *lc;
3261 : :
3262 : : /*
3263 : : * To avoid doing strictness checks on more quals than necessary, we want
3264 : : * to stop descending the jointree as soon as there are no outer joins
3265 : : * below our current point. This consideration forces a two-pass process.
3266 : : * The first pass gathers information about which base rels appear below
3267 : : * each side of each join clause, about whether there are outer join(s)
3268 : : * below each side of each join clause, and about which base rels are from
3269 : : * the nullable side of those outer join(s). The second pass examines
3270 : : * qual clauses and changes join types as it descends the tree.
3271 : : */
1191 3272 : 25946 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
3273 : :
3274 : : /* planner.c shouldn't have called me if no outer joins */
3275 [ + - - + ]: 25946 : if (state1 == NULL || !state1->contains_outer)
8320 tgl@sss.pgh.pa.us 3276 [ # # ]:UBC 0 : elog(ERROR, "so where are the outer joins?");
3277 : :
1191 tgl@sss.pgh.pa.us 3278 :CBC 25946 : state2.inner_reduced = NULL;
3279 : 25946 : state2.partial_reduced = NIL;
3280 : :
7639 3281 : 25946 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
3282 : : state1, &state2,
3283 : : root, NULL, NIL);
3284 : :
3285 : : /*
3286 : : * If we successfully reduced the strength of any outer joins, we must
3287 : : * remove references to those joins as nulling rels. This is handled as
3288 : : * an additional pass, for simplicity and because we can handle all
3289 : : * fully-reduced joins in a single pass over the parse tree.
3290 : : */
1191 3291 [ + + ]: 25946 : if (!bms_is_empty(state2.inner_reduced))
3292 : : {
3293 : 2098 : root->parse = (Query *)
3294 : 2098 : remove_nulling_relids((Node *) root->parse,
3295 : 2098 : state2.inner_reduced,
3296 : : NULL);
3297 : : /* There could be references in the append_rel_list, too */
3298 : 2098 : root->append_rel_list = (List *)
3299 : 2098 : remove_nulling_relids((Node *) root->append_rel_list,
3300 : 2098 : state2.inner_reduced,
3301 : : NULL);
3302 : : }
3303 : :
3304 : : /*
3305 : : * Partially-reduced full joins have to be done one at a time, since
3306 : : * they'll each need a different setting of except_relids.
3307 : : */
3308 [ + + + + : 25985 : foreach(lc, state2.partial_reduced)
+ + ]
3309 : : {
3310 : 39 : reduce_outer_joins_partial_state *statep = lfirst(lc);
3311 : 39 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
3312 : :
3313 : 39 : root->parse = (Query *)
3314 : 39 : remove_nulling_relids((Node *) root->parse,
3315 : : full_join_relids,
3316 : 39 : statep->unreduced_side);
3317 : 39 : root->append_rel_list = (List *)
3318 : 39 : remove_nulling_relids((Node *) root->append_rel_list,
3319 : : full_join_relids,
3320 : 39 : statep->unreduced_side);
3321 : : }
8486 3322 : 25946 : }
3323 : :
3324 : : /*
3325 : : * reduce_outer_joins_pass1 - phase 1 data collection
3326 : : *
3327 : : * Returns a state node describing the given jointree node.
3328 : : */
3329 : : static reduce_outer_joins_pass1_state *
3330 : 147520 : reduce_outer_joins_pass1(Node *jtnode)
3331 : : {
3332 : : reduce_outer_joins_pass1_state *result;
3333 : :
146 michael@paquier.xyz 3334 :GNC 147520 : result = palloc_object(reduce_outer_joins_pass1_state);
8486 tgl@sss.pgh.pa.us 3335 :CBC 147520 : result->relids = NULL;
3336 : 147520 : result->contains_outer = false;
82 rguo@postgresql.org 3337 :GNC 147520 : result->nullable_rels = NULL;
8486 tgl@sss.pgh.pa.us 3338 :CBC 147520 : result->sub_states = NIL;
3339 : :
3340 [ - + ]: 147520 : if (jtnode == NULL)
8486 tgl@sss.pgh.pa.us 3341 :UBC 0 : return result;
8486 tgl@sss.pgh.pa.us 3342 [ + + ]:CBC 147520 : if (IsA(jtnode, RangeTblRef))
3343 : : {
3344 : 73640 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3345 : :
3346 : 73640 : result->relids = bms_make_singleton(varno);
3347 : : }
3348 [ + + ]: 73880 : else if (IsA(jtnode, FromExpr))
3349 : : {
3350 : 28575 : FromExpr *f = (FromExpr *) jtnode;
3351 : : ListCell *l;
3352 : :
3353 [ + - + + : 59539 : foreach(l, f->fromlist)
+ + ]
3354 : : {
3355 : : reduce_outer_joins_pass1_state *sub_state;
3356 : :
3357 : 30964 : sub_state = reduce_outer_joins_pass1(lfirst(l));
3358 : 61928 : result->relids = bms_add_members(result->relids,
3359 : 30964 : sub_state->relids);
3360 : 30964 : result->contains_outer |= sub_state->contains_outer;
82 rguo@postgresql.org 3361 :GNC 61928 : result->nullable_rels = bms_add_members(result->nullable_rels,
3362 : 30964 : sub_state->nullable_rels);
8486 tgl@sss.pgh.pa.us 3363 :CBC 30964 : result->sub_states = lappend(result->sub_states, sub_state);
3364 : : }
3365 : : }
3366 [ + - ]: 45305 : else if (IsA(jtnode, JoinExpr))
3367 : : {
3368 : 45305 : JoinExpr *j = (JoinExpr *) jtnode;
3369 : : reduce_outer_joins_pass1_state *left_state;
3370 : : reduce_outer_joins_pass1_state *right_state;
3371 : :
3372 : : /* Recurse to children */
82 rguo@postgresql.org 3373 :GNC 45305 : left_state = reduce_outer_joins_pass1(j->larg);
3374 : 45305 : right_state = reduce_outer_joins_pass1(j->rarg);
3375 : :
3376 : : /* join's own RT index is not wanted in result->relids */
3377 : 45305 : result->relids = bms_union(left_state->relids, right_state->relids);
3378 : :
3379 : : /* Store children's states for pass 2 */
3380 : 45305 : result->sub_states = list_make2(left_state, right_state);
3381 : :
3382 : : /* Collect outer join information */
3383 [ + + + + : 45305 : switch (j->jointype)
- ]
3384 : : {
3385 : 7572 : case JOIN_INNER:
3386 : : case JOIN_SEMI:
3387 : : /* No new nullability; propagate state from children */
3388 [ + + ]: 14530 : result->contains_outer = left_state->contains_outer ||
3389 [ + + ]: 6958 : right_state->contains_outer;
3390 : 15144 : result->nullable_rels = bms_union(left_state->nullable_rels,
3391 : 7572 : right_state->nullable_rels);
3392 : 7572 : break;
3393 : 35903 : case JOIN_LEFT:
3394 : : case JOIN_ANTI:
3395 : : /* RHS is nullable; LHS keeps existing status */
3396 : 35903 : result->contains_outer = true;
3397 : 71806 : result->nullable_rels = bms_union(left_state->nullable_rels,
3398 : 35903 : right_state->relids);
3399 : 35903 : break;
3400 : 960 : case JOIN_RIGHT:
3401 : : /* LHS is nullable; RHS keeps existing status */
3402 : 960 : result->contains_outer = true;
3403 : 1920 : result->nullable_rels = bms_union(left_state->relids,
3404 : 960 : right_state->nullable_rels);
3405 : 960 : break;
3406 : 870 : case JOIN_FULL:
3407 : : /* Both sides are nullable */
3408 : 870 : result->contains_outer = true;
3409 : 1740 : result->nullable_rels = bms_union(left_state->relids,
3410 : 870 : right_state->relids);
3411 : 870 : break;
82 rguo@postgresql.org 3412 :UNC 0 : default:
3413 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
3414 : : (int) j->jointype);
3415 : : break;
3416 : : }
3417 : : }
3418 : : else
8320 tgl@sss.pgh.pa.us 3419 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
3420 : : (int) nodeTag(jtnode));
8486 tgl@sss.pgh.pa.us 3421 :CBC 147520 : return result;
3422 : : }
3423 : :
3424 : : /*
3425 : : * reduce_outer_joins_pass2 - phase 2 processing
3426 : : *
3427 : : * jtnode: current jointree node
3428 : : * state1: state data collected by phase 1 for this node
3429 : : * state2: where to accumulate info about successfully-reduced joins
3430 : : * root: toplevel planner state
3431 : : * nonnullable_rels: set of base relids forced non-null by upper quals
3432 : : * forced_null_vars: multibitmapset of Vars forced null by upper quals
3433 : : *
3434 : : * Returns info in state2 about outer joins that were successfully simplified.
3435 : : * Joins that were fully reduced to inner joins are all added to
3436 : : * state2->inner_reduced. If a full join is reduced to a left join,
3437 : : * it needs its own entry in state2->partial_reduced, since that will
3438 : : * require custom processing to remove only the correct nullingrel markers.
3439 : : */
3440 : : static void
3441 : 65560 : reduce_outer_joins_pass2(Node *jtnode,
3442 : : reduce_outer_joins_pass1_state *state1,
3443 : : reduce_outer_joins_pass2_state *state2,
3444 : : PlannerInfo *root,
3445 : : Relids nonnullable_rels,
3446 : : List *forced_null_vars)
3447 : : {
3448 : : /*
3449 : : * pass 2 should never descend as far as an empty subnode or base rel,
3450 : : * because it's only called on subtrees marked as contains_outer.
3451 : : */
3452 [ - + ]: 65560 : if (jtnode == NULL)
8320 tgl@sss.pgh.pa.us 3453 [ # # ]:UBC 0 : elog(ERROR, "reached empty jointree");
8486 tgl@sss.pgh.pa.us 3454 [ - + ]:CBC 65560 : if (IsA(jtnode, RangeTblRef))
8320 tgl@sss.pgh.pa.us 3455 [ # # ]:UBC 0 : elog(ERROR, "reached base rel");
8486 tgl@sss.pgh.pa.us 3456 [ + + ]:CBC 65560 : else if (IsA(jtnode, FromExpr))
3457 : : {
3458 : 27098 : FromExpr *f = (FromExpr *) jtnode;
3459 : : ListCell *l;
3460 : : ListCell *s;
3461 : : Relids pass_nonnullable_rels;
3462 : : List *pass_forced_null_vars;
3463 : :
3464 : : /* Scan quals to see if we can add any constraints */
6473 3465 : 27098 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
3466 : 27098 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
3467 : : nonnullable_rels);
3468 : 27098 : pass_forced_null_vars = find_forced_null_vars(f->quals);
1266 3469 : 27098 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
3470 : : forced_null_vars);
3471 : : /* And recurse --- but only into interesting subtrees */
1191 3472 [ - + ]: 27098 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
3473 [ + - + + : 56450 : forboth(l, f->fromlist, s, state1->sub_states)
+ - + + +
+ + - +
+ ]
3474 : : {
3475 : 29352 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
3476 : :
8486 3477 [ + + ]: 29352 : if (sub_state->contains_outer)
1191 3478 : 27123 : reduce_outer_joins_pass2(lfirst(l), sub_state,
3479 : : state2, root,
3480 : : pass_nonnullable_rels,
3481 : : pass_forced_null_vars);
3482 : : }
6473 3483 : 27098 : bms_free(pass_nonnullable_rels);
3484 : : /* can't so easily clean up var lists, unfortunately */
3485 : : }
8486 3486 [ + - ]: 38462 : else if (IsA(jtnode, JoinExpr))
3487 : : {
3488 : 38462 : JoinExpr *j = (JoinExpr *) jtnode;
3489 : 38462 : int rtindex = j->rtindex;
3490 : 38462 : JoinType jointype = j->jointype;
1191 3491 : 38462 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
3492 : 38462 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
3493 : :
3494 : : /* Can we simplify this join? */
8486 3495 [ + + + + : 38462 : switch (jointype)
+ - ]
3496 : : {
6473 3497 : 681 : case JOIN_INNER:
3498 : 681 : break;
8486 3499 : 35565 : case JOIN_LEFT:
3500 [ + + ]: 35565 : if (bms_overlap(nonnullable_rels, right_state->relids))
3501 : 2343 : jointype = JOIN_INNER;
3502 : 35565 : break;
3503 : 960 : case JOIN_RIGHT:
3504 [ + + ]: 960 : if (bms_overlap(nonnullable_rels, left_state->relids))
3505 : 64 : jointype = JOIN_INNER;
3506 : 960 : break;
3507 : 870 : case JOIN_FULL:
3508 [ + + ]: 870 : if (bms_overlap(nonnullable_rels, left_state->relids))
3509 : : {
3510 [ + + ]: 20 : if (bms_overlap(nonnullable_rels, right_state->relids))
3511 : 10 : jointype = JOIN_INNER;
3512 : : else
3513 : : {
3514 : 10 : jointype = JOIN_LEFT;
3515 : : /* Also report partial reduction in state2 */
1191 3516 : 10 : report_reduced_full_join(state2, rtindex,
3517 : : right_state->relids);
3518 : : }
3519 : : }
3520 : : else
3521 : : {
8486 3522 [ + + ]: 850 : if (bms_overlap(nonnullable_rels, right_state->relids))
3523 : : {
3524 : 29 : jointype = JOIN_RIGHT;
3525 : : /* Also report partial reduction in state2 */
1191 3526 : 29 : report_reduced_full_join(state2, rtindex,
3527 : : left_state->relids);
3528 : : }
3529 : : }
8486 3530 : 870 : break;
6278 3531 : 386 : case JOIN_SEMI:
3532 : : case JOIN_ANTI:
3533 : :
3534 : : /*
3535 : : * These could only have been introduced by pull_up_sublinks,
3536 : : * so there's no way that upper quals could refer to their
3537 : : * righthand sides, and no point in checking. We don't expect
3538 : : * to see JOIN_RIGHT_SEMI or JOIN_RIGHT_ANTI yet.
3539 : : */
3540 : 386 : break;
8486 tgl@sss.pgh.pa.us 3541 :UBC 0 : default:
6473 3542 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
3543 : : (int) jointype);
3544 : : break;
3545 : : }
3546 : :
3547 : : /*
3548 : : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
3549 : : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
3550 : : * longer matches the internal ordering of any CoalesceExpr's built to
3551 : : * represent merged join variables. We don't care about that at
3552 : : * present, but be wary of it ...
3553 : : */
6473 tgl@sss.pgh.pa.us 3554 [ + + ]:CBC 38462 : if (jointype == JOIN_RIGHT)
3555 : : {
3556 : : Node *tmparg;
3557 : :
3558 : 925 : tmparg = j->larg;
3559 : 925 : j->larg = j->rarg;
3560 : 925 : j->rarg = tmparg;
3561 : 925 : jointype = JOIN_LEFT;
1191 3562 : 925 : right_state = linitial(state1->sub_states);
3563 : 925 : left_state = lsecond(state1->sub_states);
3564 : : }
3565 : :
3566 : : /*
3567 : : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
3568 : : * any var from the RHS was forced null by higher qual levels, but is
3569 : : * known to be non-nullable. We detect this either by seeing if the
3570 : : * join's own quals are strict for the var, or by checking if the var
3571 : : * is defined NOT NULL by table constraints (being careful to exclude
3572 : : * vars that are nullable due to lower-level outer joins). In either
3573 : : * case, the only way the higher qual clause's requirement for NULL
3574 : : * can be met is if the join fails to match, producing a null-extended
3575 : : * row. Thus, we can treat this as an anti-join.
3576 : : */
82 rguo@postgresql.org 3577 [ + + + + ]:GNC 38462 : if (jointype == JOIN_LEFT && forced_null_vars != NIL)
3578 : : {
3579 : : List *nonnullable_vars;
3580 : : Bitmapset *overlap;
3581 : :
3582 : : /* Find Vars in j->quals that must be non-null in joined rows */
1277 tgl@sss.pgh.pa.us 3583 :CBC 1117 : nonnullable_vars = find_nonnullable_vars(j->quals);
3584 : :
3585 : : /*
3586 : : * It's not sufficient to check whether nonnullable_vars and
3587 : : * forced_null_vars overlap: we need to know if the overlap
3588 : : * includes any RHS variables.
3589 : : *
3590 : : * Also check if any forced-null var is defined NOT NULL by table
3591 : : * constraints.
3592 : : */
1266 3593 : 1117 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
82 rguo@postgresql.org 3594 [ + + + + ]:GNC 1268 : if (bms_overlap(overlap, right_state->relids) ||
3595 : 151 : has_notnull_forced_var(root, forced_null_vars, right_state))
6473 tgl@sss.pgh.pa.us 3596 :CBC 986 : jointype = JOIN_ANTI;
3597 : : }
3598 : :
3599 : : /*
3600 : : * Apply the jointype change, if any, to both jointree node and RTE.
3601 : : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3602 : : */
6278 3603 [ + + + + ]: 38462 : if (rtindex && jointype != j->jointype)
3604 : : {
7639 3605 : 4338 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3606 : :
8486 3607 [ - + ]: 4338 : Assert(rte->rtekind == RTE_JOIN);
3608 [ - + ]: 4338 : Assert(rte->jointype == j->jointype);
6278 3609 : 4338 : rte->jointype = jointype;
1191 3610 [ + + ]: 4338 : if (jointype == JOIN_INNER)
3611 : 2417 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3612 : : rtindex);
3613 : : }
6278 3614 : 38462 : j->jointype = jointype;
3615 : :
3616 : : /* Only recurse if there's more to do below here */
8486 3617 [ + + + + ]: 38462 : if (left_state->contains_outer || right_state->contains_outer)
3618 : : {
3619 : : Relids local_nonnullable_rels;
3620 : : List *local_forced_null_vars;
3621 : : Relids pass_nonnullable_rels;
3622 : : List *pass_forced_null_vars;
3623 : :
3624 : : /*
3625 : : * If this join is (now) inner, we can add any constraints its
3626 : : * quals provide to those we got from above. But if it is outer,
3627 : : * we can pass down the local constraints only into the nullable
3628 : : * side, because an outer join never eliminates any rows from its
3629 : : * non-nullable side. Also, there is no point in passing upper
3630 : : * constraints into the nullable side, since if there were any
3631 : : * we'd have been able to reduce the join. (In the case of upper
3632 : : * forced-null constraints, we *must not* pass them into the
3633 : : * nullable side --- they either applied here, or not.) The upshot
3634 : : * is that we pass either the local or the upper constraints,
3635 : : * never both, to the children of an outer join.
3636 : : *
3637 : : * Note that a SEMI join works like an inner join here: it's okay
3638 : : * to pass down both local and upper constraints. (There can't be
3639 : : * any upper constraints affecting its inner side, but it's not
3640 : : * worth having a separate code path to avoid passing them.)
3641 : : *
3642 : : * At a FULL join we just punt and pass nothing down --- is it
3643 : : * possible to be smarter?
3644 : : */
8485 3645 [ + + ]: 12437 : if (jointype != JOIN_FULL)
3646 : : {
6473 3647 : 12329 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3648 : 12329 : local_forced_null_vars = find_forced_null_vars(j->quals);
5574 3649 [ + + + + ]: 12329 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3650 : : {
3651 : : /* OK to merge upper and local constraints */
6473 3652 : 1494 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3653 : : nonnullable_rels);
1266 3654 : 1494 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3655 : : forced_null_vars);
3656 : : }
3657 : : }
3658 : : else
3659 : : {
3660 : : /* no use in calculating these */
6473 3661 : 108 : local_nonnullable_rels = NULL;
3662 : 108 : local_forced_null_vars = NIL;
3663 : : }
3664 : :
8486 3665 [ + + ]: 12437 : if (left_state->contains_outer)
3666 : : {
5574 3667 [ + + + + ]: 11792 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3668 : : {
3669 : : /* pass union of local and upper constraints */
6473 3670 : 1323 : pass_nonnullable_rels = local_nonnullable_rels;
3671 : 1323 : pass_forced_null_vars = local_forced_null_vars;
3672 : : }
5504 bruce@momjian.us 3673 [ + + ]: 10469 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3674 : : {
3675 : : /* can't pass local constraints to non-nullable side */
6473 tgl@sss.pgh.pa.us 3676 : 10389 : pass_nonnullable_rels = nonnullable_rels;
3677 : 10389 : pass_forced_null_vars = forced_null_vars;
3678 : : }
3679 : : else
3680 : : {
3681 : : /* no constraints pass through JOIN_FULL */
3682 : 80 : pass_nonnullable_rels = NULL;
3683 : 80 : pass_forced_null_vars = NIL;
3684 : : }
1191 3685 : 11792 : reduce_outer_joins_pass2(j->larg, left_state,
3686 : : state2, root,
3687 : : pass_nonnullable_rels,
3688 : : pass_forced_null_vars);
3689 : : }
3690 : :
8486 3691 [ + + ]: 12437 : if (right_state->contains_outer)
3692 : : {
3240 3693 [ + + ]: 699 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3694 : : {
3695 : : /* pass appropriate constraints, per comment above */
6473 3696 : 671 : pass_nonnullable_rels = local_nonnullable_rels;
3697 : 671 : pass_forced_null_vars = local_forced_null_vars;
3698 : : }
3699 : : else
3700 : : {
3701 : : /* no constraints pass through JOIN_FULL */
3702 : 28 : pass_nonnullable_rels = NULL;
3703 : 28 : pass_forced_null_vars = NIL;
3704 : : }
1191 3705 : 699 : reduce_outer_joins_pass2(j->rarg, right_state,
3706 : : state2, root,
3707 : : pass_nonnullable_rels,
3708 : : pass_forced_null_vars);
3709 : : }
6473 3710 : 12437 : bms_free(local_nonnullable_rels);
3711 : : }
3712 : : }
3713 : : else
8320 tgl@sss.pgh.pa.us 3714 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
3715 : : (int) nodeTag(jtnode));
8486 tgl@sss.pgh.pa.us 3716 :CBC 65560 : }
3717 : :
3718 : : /* Helper for reduce_outer_joins_pass2 */
3719 : : static void
1191 3720 : 39 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3721 : : int rtindex, Relids relids)
3722 : : {
3723 : : reduce_outer_joins_partial_state *statep;
3724 : :
146 michael@paquier.xyz 3725 :GNC 39 : statep = palloc_object(reduce_outer_joins_partial_state);
1191 tgl@sss.pgh.pa.us 3726 :CBC 39 : statep->full_join_rti = rtindex;
3727 : 39 : statep->unreduced_side = relids;
3728 : 39 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3729 : 39 : }
3730 : :
3731 : : /*
3732 : : * has_notnull_forced_var
3733 : : * Check if "forced_null_vars" contains any Vars belonging to the subtree
3734 : : * indicated by "right_state" that are known to be non-nullable due to
3735 : : * table constraints.
3736 : : *
3737 : : * Note that we must also consider the situation where a NOT NULL Var can be
3738 : : * nulled by lower-level outer joins.
3739 : : *
3740 : : * Helper for reduce_outer_joins_pass2.
3741 : : */
3742 : : static bool
82 rguo@postgresql.org 3743 :GNC 151 : has_notnull_forced_var(PlannerInfo *root, List *forced_null_vars,
3744 : : reduce_outer_joins_pass1_state *right_state)
3745 : : {
3746 : 151 : int varno = -1;
3747 : :
3748 [ + - + + : 1218 : foreach_node(Bitmapset, attrs, forced_null_vars)
+ + ]
3749 : : {
3750 : : RangeTblEntry *rte;
3751 : : Bitmapset *notnullattnums;
3752 : 956 : Bitmapset *forcednullattnums = NULL;
3753 : : int attno;
3754 : :
3755 : 956 : varno++;
3756 : :
3757 : : /* Skip empty bitmaps */
3758 [ + + ]: 956 : if (bms_is_empty(attrs))
3759 : 805 : continue;
3760 : :
3761 : : /* Skip Vars that do not belong to the target relations */
3762 [ + + ]: 151 : if (!bms_is_member(varno, right_state->relids))
3763 : 65 : continue;
3764 : :
3765 : : /*
3766 : : * Skip Vars that can be nulled by lower-level outer joins within the
3767 : : * given subtree. These Vars might be NULL even if the schema defines
3768 : : * them as NOT NULL.
3769 : : */
3770 [ + + ]: 86 : if (bms_is_member(varno, right_state->nullable_rels))
3771 : 5 : continue;
3772 : :
3773 : : /*
3774 : : * Iterate over attributes and adjust the bitmap indexes by
3775 : : * FirstLowInvalidHeapAttributeNumber to get the actual attribute
3776 : : * numbers.
3777 : : */
3778 : 81 : attno = -1;
3779 [ + + ]: 162 : while ((attno = bms_next_member(attrs, attno)) >= 0)
3780 : : {
3781 : 81 : AttrNumber real_attno = attno + FirstLowInvalidHeapAttributeNumber;
3782 : :
3783 : : /* system columns cannot be NULL */
3784 [ - + ]: 81 : if (real_attno < 0)
3785 : 20 : return true;
3786 : :
3787 : 81 : forcednullattnums = bms_add_member(forcednullattnums, real_attno);
3788 : : }
3789 : :
3790 : 81 : rte = rt_fetch(varno, root->parse->rtable);
3791 : :
3792 : : /* We can only reason about ordinary relations */
54 3793 [ + + ]: 81 : if (rte->rtekind != RTE_RELATION)
3794 : : {
3795 : 31 : bms_free(forcednullattnums);
3796 : 31 : continue;
3797 : : }
3798 : :
3799 : : /*
3800 : : * We must skip inheritance parent tables, as some child tables may
3801 : : * have a NOT NULL constraint for a column while others may not. This
3802 : : * cannot happen with partitioned tables, though.
3803 : : */
82 3804 [ - + - - ]: 50 : if (rte->inh && rte->relkind != RELKIND_PARTITIONED_TABLE)
3805 : : {
82 rguo@postgresql.org 3806 :UNC 0 : bms_free(forcednullattnums);
3807 : 0 : continue;
3808 : : }
3809 : :
3810 : : /* Get the column not-null constraint information for this relation */
82 rguo@postgresql.org 3811 :GNC 50 : notnullattnums = find_relation_notnullatts(root, rte->relid);
3812 : :
3813 : : /*
3814 : : * Check if any forced-null attributes are defined as NOT NULL by
3815 : : * table constraints.
3816 : : */
3817 [ + + ]: 50 : if (bms_overlap(notnullattnums, forcednullattnums))
3818 : : {
3819 : 20 : bms_free(forcednullattnums);
3820 : 20 : return true;
3821 : : }
3822 : :
3823 : 30 : bms_free(forcednullattnums);
3824 : : }
3825 : :
3826 : 131 : return false;
3827 : : }
3828 : :
3829 : :
3830 : : /*
3831 : : * remove_useless_result_rtes
3832 : : * Attempt to remove RTE_RESULT RTEs from the join tree.
3833 : : * Also, elide single-child FromExprs where possible.
3834 : : *
3835 : : * We can remove RTE_RESULT entries from the join tree using the knowledge
3836 : : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3837 : : * if one is inner-joined to anything else, we can delete it. Optimizations
3838 : : * are also possible for some outer-join cases, as detailed below.
3839 : : *
3840 : : * This pass also replaces single-child FromExprs with their child node
3841 : : * where possible. It's appropriate to do that here and not earlier because
3842 : : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3843 : : * child. We can remove such a FromExpr if its quals are empty, or if it's
3844 : : * semantically valid to merge the quals into those of the parent node.
3845 : : * While removing unnecessary join tree nodes has some micro-efficiency value,
3846 : : * the real reason to do this is to eliminate cases where the nullable side of
3847 : : * an outer join node is a FromExpr whose single child is another outer join.
3848 : : * To correctly determine whether the two outer joins can commute,
3849 : : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3850 : : * degenerate quals of the upper outer join. The best way to do that is to
3851 : : * make them actually *be* quals of the upper join, by dropping the FromExpr
3852 : : * and hoisting the quals up into the upper join's quals. (Note that there is
3853 : : * no hazard when the intermediate FromExpr has multiple children, since then
3854 : : * it represents an inner join that cannot commute with the upper outer join.)
3855 : : * As long as we have to do that, we might as well elide such FromExprs
3856 : : * everywhere.
3857 : : *
3858 : : * Some of these optimizations depend on recognizing empty (constant-true)
3859 : : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3860 : : * optimization pass after expression preprocessing, since that will have
3861 : : * eliminated constant-true quals, allowing more cases to be recognized as
3862 : : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3863 : : * is that we pulled up a subquery or VALUES clause, thus very possibly
3864 : : * replacing Vars with constants, making it more likely that a qual can be
3865 : : * reduced to constant true. Also, because some optimizations depend on
3866 : : * the outer-join type, it's best to have done reduce_outer_joins() first.
3867 : : *
3868 : : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3869 : : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3870 : : * we must not reduce the phrels set to empty. If that would happen, and
3871 : : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3872 : : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3873 : : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3874 : : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3875 : : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3876 : : * the inner join instead. This is OK because we really only care that PHVs
3877 : : * are evaluated above or below the correct outer joins. We can't, however,
3878 : : * postpone the evaluation of a PHV to above where it is used; so there are
3879 : : * some checks below on whether output PHVs are laterally referenced in the
3880 : : * other join input rel(s).
3881 : : *
3882 : : * We used to try to do this work as part of pull_up_subqueries() where the
3883 : : * potentially-optimizable cases get introduced; but it's way simpler, and
3884 : : * more effective, to do it separately.
3885 : : */
3886 : : void
2654 tgl@sss.pgh.pa.us 3887 :CBC 166419 : remove_useless_result_rtes(PlannerInfo *root)
3888 : : {
1191 3889 : 166419 : Relids dropped_outer_joins = NULL;
3890 : : ListCell *cell;
3891 : :
3892 : : /* Top level of jointree must always be a FromExpr */
2654 3893 [ - + ]: 166419 : Assert(IsA(root->parse->jointree, FromExpr));
3894 : : /* Recurse ... */
3895 : 332838 : root->parse->jointree = (FromExpr *)
1191 3896 : 166419 : remove_useless_results_recurse(root,
3897 : 166419 : (Node *) root->parse->jointree,
3898 : : NULL,
3899 : : &dropped_outer_joins);
3900 : : /* We should still have a FromExpr */
2654 3901 [ - + ]: 166419 : Assert(IsA(root->parse->jointree, FromExpr));
3902 : :
3903 : : /*
3904 : : * If we removed any outer-join nodes from the jointree, run around and
3905 : : * remove references to those joins as nulling rels. (There could be such
3906 : : * references in PHVs that we pulled up out of the original subquery that
3907 : : * the RESULT rel replaced. This is kosher on the grounds that we now
3908 : : * know that such an outer join wouldn't really have nulled anything.) We
3909 : : * don't do this during the main recursion, for simplicity and because we
3910 : : * can handle all such joins in a single pass over the parse tree.
3911 : : */
1191 3912 [ + + ]: 166419 : if (!bms_is_empty(dropped_outer_joins))
3913 : : {
3914 : 50 : root->parse = (Query *)
3915 : 50 : remove_nulling_relids((Node *) root->parse,
3916 : : dropped_outer_joins,
3917 : : NULL);
3918 : : /* There could be references in the append_rel_list, too */
3919 : 50 : root->append_rel_list = (List *)
3920 : 50 : remove_nulling_relids((Node *) root->append_rel_list,
3921 : : dropped_outer_joins,
3922 : : NULL);
3923 : : }
3924 : :
3925 : : /*
3926 : : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3927 : : * must do that for any RTE_RESULT that we just removed. But one for a
3928 : : * RTE that we did not remove can be dropped anyway: since the RTE has
3929 : : * only one possible output row, there is no need for EPQ to mark and
3930 : : * restore that row.
3931 : : *
3932 : : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3933 : : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3934 : : * RTE_RESULT, which the executor has no support for.
3935 : : */
2486 3936 [ + + + + : 167996 : foreach(cell, root->rowMarks)
+ + ]
3937 : : {
2654 3938 : 1577 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3939 : :
3940 [ + + ]: 1577 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
2486 3941 : 656 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3942 : : }
2654 3943 : 166419 : }
3944 : :
3945 : : /*
3946 : : * remove_useless_results_recurse
3947 : : * Recursive guts of remove_useless_result_rtes.
3948 : : *
3949 : : * This recursively processes the jointree and returns a modified jointree.
3950 : : * In addition, the RT indexes of any removed outer-join nodes are added to
3951 : : * *dropped_outer_joins.
3952 : : *
3953 : : * jtnode is the current jointree node. If it could be valid to merge
3954 : : * its quals into those of the parent node, parent_quals should point to
3955 : : * the parent's quals list; otherwise, pass NULL for parent_quals.
3956 : : * (Note that in some cases, parent_quals points to the quals of a parent
3957 : : * more than one level up in the tree.)
3958 : : */
3959 : : static Node *
1191 3960 : 438357 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3961 : : Node **parent_quals,
3962 : : Relids *dropped_outer_joins)
3963 : : {
2654 3964 [ - + ]: 438357 : Assert(jtnode != NULL);
3965 [ + + ]: 438357 : if (IsA(jtnode, RangeTblRef))
3966 : : {
3967 : : /* Can't immediately do anything with a RangeTblRef */
3968 : : }
3969 [ + + ]: 220519 : else if (IsA(jtnode, FromExpr))
3970 : : {
3971 : 172088 : FromExpr *f = (FromExpr *) jtnode;
3972 : 172088 : Relids result_relids = NULL;
3973 : : ListCell *cell;
3974 : :
3975 : : /*
3976 : : * We can drop RTE_RESULT rels from the fromlist so long as at least
3977 : : * one child remains, since joining to a one-row table changes
3978 : : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3979 : : * are needed by some sibling. The cleanup transformation below would
3980 : : * reassign the PHVs to be computed at the join, which is too late for
3981 : : * the sibling's use.) The easiest way to mechanize this rule is to
3982 : : * modify the list in-place.
3983 : : */
2486 3984 [ + - + + : 347164 : foreach(cell, f->fromlist)
+ + ]
3985 : : {
2654 3986 : 175076 : Node *child = (Node *) lfirst(cell);
3987 : : int varno;
3988 : :
3989 : : /* Recursively transform child, allowing it to push up quals ... */
1191 3990 : 175076 : child = remove_useless_results_recurse(root, child,
3991 : : &f->quals,
3992 : : dropped_outer_joins);
3993 : : /* ... and stick it back into the tree */
2654 3994 : 175076 : lfirst(cell) = child;
3995 : :
3996 : : /*
3997 : : * If it's an RTE_RESULT with at least one sibling, and no sibling
3998 : : * references dependent PHVs, we can drop it. We don't yet know
3999 : : * what the inner join's final relid set will be, so postpone
4000 : : * cleanup of PHVs etc till after this loop.
4001 : : */
4002 [ + + + + ]: 179874 : if (list_length(f->fromlist) > 1 &&
2334 4003 : 4798 : (varno = get_result_relid(root, child)) != 0 &&
4004 [ + + ]: 289 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
4005 : : {
2486 4006 : 269 : f->fromlist = foreach_delete_current(f->fromlist, cell);
2654 4007 : 269 : result_relids = bms_add_member(result_relids, varno);
4008 : : }
4009 : : }
4010 : :
4011 : : /*
4012 : : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
4013 : : * inefficient if there's more than one, but it seems better to
4014 : : * optimize the support code for the single-relid case.
4015 : : */
4016 [ + + ]: 172088 : if (result_relids)
4017 : : {
4018 : 259 : int varno = -1;
4019 : :
4020 [ + + ]: 528 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
4021 : 269 : remove_result_refs(root, varno, (Node *) f);
4022 : : }
4023 : :
4024 : : /*
4025 : : * If the FromExpr now has only one child, see if we can elide it.
4026 : : * This is always valid if there are no quals, except at the top of
4027 : : * the jointree (since Query.jointree is required to point to a
4028 : : * FromExpr). Otherwise, we can do it if we can push the quals up to
4029 : : * the parent node.
4030 : : *
4031 : : * Note: while it would not be terribly hard to generalize this
4032 : : * transformation to merge multi-child FromExprs into their parent
4033 : : * FromExpr, that risks making the parent join too expensive to plan.
4034 : : * We leave it to later processing to decide heuristically whether
4035 : : * that's a good idea. Pulling up a single child is always OK,
4036 : : * however.
4037 : : */
1191 4038 [ + + ]: 172088 : if (list_length(f->fromlist) == 1 &&
4039 [ + + ]: 170452 : f != root->parse->jointree &&
4040 [ + + + + ]: 5468 : (f->quals == NULL || parent_quals != NULL))
4041 : : {
4042 : : /*
4043 : : * Merge any quals up to parent. They should be in implicit-AND
4044 : : * format by now, so we just need to concatenate lists. Put the
4045 : : * child quals at the front, on the grounds that they should
4046 : : * nominally be evaluated earlier.
4047 : : */
4048 [ + + ]: 2283 : if (f->quals != NULL)
4049 : 1173 : *parent_quals = (Node *)
4050 : 1173 : list_concat(castNode(List, f->quals),
4051 : 1173 : castNode(List, *parent_quals));
2654 4052 : 2283 : return (Node *) linitial(f->fromlist);
4053 : : }
4054 : : }
4055 [ + - ]: 48431 : else if (IsA(jtnode, JoinExpr))
4056 : : {
4057 : 48431 : JoinExpr *j = (JoinExpr *) jtnode;
4058 : : int varno;
4059 : :
4060 : : /*
4061 : : * First, recurse. We can absorb pushed-up FromExpr quals from either
4062 : : * child into this node if the jointype is INNER, since then this is
4063 : : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
4064 : : * quals from the RHS child into the current node, as they're
4065 : : * essentially degenerate quals of the outer join. Moreover, if we've
4066 : : * been passed down a parent_quals pointer then we can allow quals of
4067 : : * the LHS child to be absorbed into the parent. (This is important
4068 : : * to ensure we remove single-child FromExprs immediately below
4069 : : * commutable left joins.) For other jointypes, we can't move child
4070 : : * quals up, or at least there's no particular reason to.
4071 : : */
1191 4072 : 48431 : j->larg = remove_useless_results_recurse(root, j->larg,
4073 [ + + ]: 48431 : (j->jointype == JOIN_INNER) ?
4074 : : &j->quals :
1050 4075 : 38037 : (j->jointype == JOIN_LEFT) ?
4076 [ + + ]: 38037 : parent_quals : NULL,
4077 : : dropped_outer_joins);
1191 4078 : 48431 : j->rarg = remove_useless_results_recurse(root, j->rarg,
4079 [ + + ]: 48431 : (j->jointype == JOIN_INNER ||
4080 [ + + ]: 38037 : j->jointype == JOIN_LEFT) ?
4081 : : &j->quals : NULL,
4082 : : dropped_outer_joins);
4083 : :
4084 : : /* Apply join-type-specific optimization rules */
2654 4085 [ + + + + : 48431 : switch (j->jointype)
- ]
4086 : : {
4087 : 10394 : case JOIN_INNER:
4088 : :
4089 : : /*
4090 : : * An inner join is equivalent to a FromExpr, so if either
4091 : : * side was simplified to an RTE_RESULT rel, we can replace
4092 : : * the join with a FromExpr with just the other side.
4093 : : * Furthermore, we can elide that FromExpr according to the
4094 : : * same rules as above.
4095 : : *
4096 : : * Just as in the FromExpr case, we can't simplify if the
4097 : : * other input rel references any PHVs that are marked as to
4098 : : * be evaluated at the RTE_RESULT rel, because we can't
4099 : : * postpone their evaluation in that case. But we only have
4100 : : * to check this in cases where it's syntactically legal for
4101 : : * the other input to have a LATERAL reference to the
4102 : : * RTE_RESULT rel. Only RHSes of inner and left joins are
4103 : : * allowed to have such refs.
4104 : : */
2334 4105 [ + + ]: 10394 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
4106 [ + - ]: 84 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
4107 : : {
2654 4108 : 84 : remove_result_refs(root, varno, j->rarg);
1191 4109 [ + + + + ]: 84 : if (j->quals != NULL && parent_quals == NULL)
2654 4110 : 10 : jtnode = (Node *)
4111 : 10 : makeFromExpr(list_make1(j->rarg), j->quals);
4112 : : else
4113 : : {
4114 : : /* Merge any quals up to parent */
1191 4115 [ + + ]: 74 : if (j->quals != NULL)
4116 : 56 : *parent_quals = (Node *)
4117 : 56 : list_concat(castNode(List, j->quals),
4118 : 56 : castNode(List, *parent_quals));
2654 4119 : 74 : jtnode = j->rarg;
4120 : : }
4121 : : }
4122 [ + + ]: 10310 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
4123 : : {
4124 : 560 : remove_result_refs(root, varno, j->larg);
1191 4125 [ + + + + ]: 560 : if (j->quals != NULL && parent_quals == NULL)
2654 4126 : 10 : jtnode = (Node *)
4127 : 10 : makeFromExpr(list_make1(j->larg), j->quals);
4128 : : else
4129 : : {
4130 : : /* Merge any quals up to parent */
1191 4131 [ + + ]: 550 : if (j->quals != NULL)
4132 : 394 : *parent_quals = (Node *)
4133 : 394 : list_concat(castNode(List, j->quals),
4134 : 394 : castNode(List, *parent_quals));
2654 4135 : 550 : jtnode = j->larg;
4136 : : }
4137 : : }
4138 : 10394 : break;
4139 : 33171 : case JOIN_LEFT:
4140 : :
4141 : : /*
4142 : : * We can simplify this case if the RHS is an RTE_RESULT, with
4143 : : * two different possibilities:
4144 : : *
4145 : : * If the qual is empty (JOIN ON TRUE), then the join can be
4146 : : * strength-reduced to a plain inner join, since each LHS row
4147 : : * necessarily has exactly one join partner. So we can always
4148 : : * discard the RHS, much as in the JOIN_INNER case above.
4149 : : * (Again, the LHS could not contain a lateral reference to
4150 : : * the RHS.)
4151 : : *
4152 : : * Otherwise, it's still true that each LHS row should be
4153 : : * returned exactly once, and since the RHS returns no columns
4154 : : * (unless there are PHVs that have to be evaluated there), we
4155 : : * don't much care if it's null-extended or not. So in this
4156 : : * case also, we can just ignore the qual and discard the left
4157 : : * join.
4158 : : */
4159 [ + + ]: 33171 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
4160 [ + + ]: 109 : (j->quals == NULL ||
2334 4161 [ - + ]: 59 : !find_dependent_phvs(root, varno)))
4162 : : {
2654 4163 : 50 : remove_result_refs(root, varno, j->larg);
1191 4164 : 50 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
4165 : : j->rtindex);
2654 4166 : 50 : jtnode = j->larg;
4167 : : }
4168 : 33171 : break;
4169 : 2721 : case JOIN_SEMI:
4170 : :
4171 : : /*
4172 : : * We may simplify this case if the RHS is an RTE_RESULT; the
4173 : : * join qual becomes effectively just a filter qual for the
4174 : : * LHS, since we should either return the LHS row or not. The
4175 : : * filter clause must go into a new FromExpr if we can't push
4176 : : * it up to the parent.
4177 : : *
4178 : : * There is a fine point about PHVs that are supposed to be
4179 : : * evaluated at the RHS. Such PHVs could only appear in the
4180 : : * semijoin's qual, since the rest of the query cannot
4181 : : * reference any outputs of the semijoin's RHS. Therefore,
4182 : : * they can't actually go to null before being examined, and
4183 : : * it'd be OK to just remove the PHV wrapping. We don't have
4184 : : * infrastructure for that, but remove_result_refs() will
4185 : : * relabel them as to be evaluated at the LHS, which is fine.
4186 : : *
4187 : : * Also, we don't need to worry about removing traces of the
4188 : : * join's rtindex, since it hasn't got one.
4189 : : */
4190 [ + + ]: 2721 : if ((varno = get_result_relid(root, j->rarg)) != 0)
4191 : : {
1191 4192 [ - + ]: 30 : Assert(j->rtindex == 0);
2654 4193 : 30 : remove_result_refs(root, varno, j->larg);
1191 4194 [ + - - + ]: 30 : if (j->quals != NULL && parent_quals == NULL)
2654 tgl@sss.pgh.pa.us 4195 :UBC 0 : jtnode = (Node *)
4196 : 0 : makeFromExpr(list_make1(j->larg), j->quals);
4197 : : else
4198 : : {
4199 : : /* Merge any quals up to parent */
1191 tgl@sss.pgh.pa.us 4200 [ + - ]:CBC 30 : if (j->quals != NULL)
4201 : 30 : *parent_quals = (Node *)
4202 : 30 : list_concat(castNode(List, j->quals),
4203 : 30 : castNode(List, *parent_quals));
2654 4204 : 30 : jtnode = j->larg;
4205 : : }
4206 : : }
4207 : 2721 : break;
4208 : 2145 : case JOIN_FULL:
4209 : : case JOIN_ANTI:
4210 : : /* We have no special smarts for these cases */
4211 : 2145 : break;
2654 tgl@sss.pgh.pa.us 4212 :UBC 0 : default:
4213 : : /* Note: JOIN_RIGHT should be gone at this point */
4214 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
4215 : : (int) j->jointype);
4216 : : break;
4217 : : }
4218 : : }
4219 : : else
4220 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
4221 : : (int) nodeTag(jtnode));
2654 tgl@sss.pgh.pa.us 4222 :CBC 436074 : return jtnode;
4223 : : }
4224 : :
4225 : : /*
4226 : : * get_result_relid
4227 : : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
4228 : : * otherwise return 0.
4229 : : */
4230 : : static int
4231 : 61394 : get_result_relid(PlannerInfo *root, Node *jtnode)
4232 : : {
4233 : : int varno;
4234 : :
4235 [ + + ]: 61394 : if (!IsA(jtnode, RangeTblRef))
4236 : 6346 : return 0;
4237 : 55048 : varno = ((RangeTblRef *) jtnode)->rtindex;
4238 [ + + ]: 55048 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
4239 : 53976 : return 0;
4240 : 1072 : return varno;
4241 : : }
4242 : :
4243 : : /*
4244 : : * remove_result_refs
4245 : : * Helper routine for dropping an unneeded RTE_RESULT RTE.
4246 : : *
4247 : : * This doesn't physically remove the RTE from the jointree, because that's
4248 : : * more easily handled in remove_useless_results_recurse. What it does do
4249 : : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
4250 : : * that may reference the RTE. Be sure to call this at a point where the
4251 : : * jointree is valid (no disconnected nodes).
4252 : : *
4253 : : * Note that we don't need to process the append_rel_list, since RTEs
4254 : : * referenced directly in the jointree won't be appendrel members.
4255 : : *
4256 : : * varno is the RTE_RESULT's relid.
4257 : : * newjtloc is the jointree location at which any PHVs referencing the
4258 : : * RTE_RESULT should be evaluated instead.
4259 : : */
4260 : : static void
4261 : 993 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
4262 : : {
4263 : : /* Fix up PlaceHolderVars as needed */
4264 : : /* If there are no PHVs anywhere, we can skip this bit */
4265 [ + + ]: 993 : if (root->glob->lastPHId != 0)
4266 : : {
4267 : : Relids subrelids;
4268 : :
1191 4269 : 198 : subrelids = get_relids_in_jointree(newjtloc, true, false);
2654 4270 [ - + ]: 198 : Assert(!bms_is_empty(subrelids));
4271 : 198 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
1230 4272 : 198 : fix_append_rel_relids(root, varno, subrelids);
4273 : : }
4274 : :
4275 : : /*
4276 : : * We also need to remove any PlanRowMark referencing the RTE, but we
4277 : : * postpone that work until we return to remove_useless_result_rtes.
4278 : : */
2654 4279 : 993 : }
4280 : :
4281 : :
4282 : : /*
4283 : : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
4284 : : * exactly the given varno?
4285 : : *
4286 : : * find_dependent_phvs should be used when we want to see if there are
4287 : : * any such PHVs anywhere in the Query. Another use-case is to see if
4288 : : * a subtree of the join tree contains such PHVs; but for that, we have
4289 : : * to look not only at the join tree nodes themselves but at the
4290 : : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
4291 : : */
4292 : :
4293 : : typedef struct
4294 : : {
4295 : : Relids relids;
4296 : : int sublevels_up;
4297 : : } find_dependent_phvs_context;
4298 : :
4299 : : static bool
4300 : 1729 : find_dependent_phvs_walker(Node *node,
4301 : : find_dependent_phvs_context *context)
4302 : : {
4303 [ + + ]: 1729 : if (node == NULL)
4304 : 451 : return false;
4305 [ + + ]: 1278 : if (IsA(node, PlaceHolderVar))
4306 : : {
4307 : 114 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4308 : :
4309 [ + - + + ]: 228 : if (phv->phlevelsup == context->sublevels_up &&
4310 : 114 : bms_equal(context->relids, phv->phrels))
4311 : 79 : return true;
4312 : : /* fall through to examine children */
4313 : : }
4314 [ + + ]: 1199 : if (IsA(node, Query))
4315 : : {
4316 : : /* Recurse into subselects */
4317 : : bool result;
4318 : :
4319 : 40 : context->sublevels_up++;
4320 : 40 : result = query_tree_walker((Query *) node,
4321 : : find_dependent_phvs_walker,
4322 : : context, 0);
4323 : 40 : context->sublevels_up--;
4324 : 40 : return result;
4325 : : }
4326 : : /* Shouldn't need to handle most planner auxiliary nodes here */
4327 [ - + ]: 1159 : Assert(!IsA(node, SpecialJoinInfo));
4328 [ - + ]: 1159 : Assert(!IsA(node, PlaceHolderInfo));
4329 [ - + ]: 1159 : Assert(!IsA(node, MinMaxAggInfo));
4330 : :
523 peter@eisentraut.org 4331 : 1159 : return expression_tree_walker(node, find_dependent_phvs_walker, context);
4332 : : }
4333 : :
4334 : : static bool
2334 tgl@sss.pgh.pa.us 4335 : 59 : find_dependent_phvs(PlannerInfo *root, int varno)
4336 : : {
4337 : : find_dependent_phvs_context context;
4338 : :
4339 : : /* If there are no PHVs anywhere, we needn't work hard */
4340 [ - + ]: 59 : if (root->glob->lastPHId == 0)
2334 tgl@sss.pgh.pa.us 4341 :UBC 0 : return false;
4342 : :
2654 tgl@sss.pgh.pa.us 4343 :CBC 59 : context.relids = bms_make_singleton(varno);
4344 : 59 : context.sublevels_up = 0;
4345 : :
523 peter@eisentraut.org 4346 [ + - ]: 59 : if (query_tree_walker(root->parse, find_dependent_phvs_walker, &context, 0))
1191 tgl@sss.pgh.pa.us 4347 : 59 : return true;
4348 : : /* The append_rel_list could be populated already, so check it too */
1191 tgl@sss.pgh.pa.us 4349 [ # # ]:UBC 0 : if (expression_tree_walker((Node *) root->append_rel_list,
4350 : : find_dependent_phvs_walker,
4351 : : &context))
4352 : 0 : return true;
4353 : 0 : return false;
4354 : : }
4355 : :
4356 : : static bool
2334 tgl@sss.pgh.pa.us 4357 :CBC 373 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
4358 : : {
4359 : : find_dependent_phvs_context context;
4360 : : Relids subrelids;
4361 : : int relid;
4362 : :
4363 : : /* If there are no PHVs anywhere, we needn't work hard */
4364 [ + + ]: 373 : if (root->glob->lastPHId == 0)
4365 : 318 : return false;
4366 : :
4367 : 55 : context.relids = bms_make_singleton(varno);
4368 : 55 : context.sublevels_up = 0;
4369 : :
4370 : : /*
4371 : : * See if the jointree fragment itself contains references (in join quals)
4372 : : */
4373 [ - + ]: 55 : if (find_dependent_phvs_walker(node, &context))
2334 tgl@sss.pgh.pa.us 4374 :UBC 0 : return true;
4375 : :
4376 : : /*
4377 : : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
4378 : : * since they should be flattened already, so their join alias lists no
4379 : : * longer matter), and tediously check each RTE. We can ignore RTEs that
4380 : : * are not marked LATERAL, though, since they couldn't possibly contain
4381 : : * any cross-references to other RTEs.
4382 : : */
1191 tgl@sss.pgh.pa.us 4383 :CBC 55 : subrelids = get_relids_in_jointree(node, false, false);
2334 4384 : 55 : relid = -1;
4385 [ + + ]: 120 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
4386 : : {
4387 : 85 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
4388 : :
4389 [ + + + - ]: 105 : if (rte->lateral &&
523 peter@eisentraut.org 4390 : 20 : range_table_entry_walker(rte, find_dependent_phvs_walker, &context, 0))
2334 tgl@sss.pgh.pa.us 4391 : 20 : return true;
4392 : : }
4393 : :
4394 : 35 : return false;
4395 : : }
4396 : :
4397 : : /*
4398 : : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
4399 : : * a subquery or removing an RTE_RESULT jointree item
4400 : : *
4401 : : * Find any PlaceHolderVar nodes in the given tree that reference the
4402 : : * pulled-up relid, and change them to reference the replacement relid(s).
4403 : : *
4404 : : * NOTE: although this has the form of a walker, we cheat and modify the
4405 : : * nodes in-place. This should be OK since the tree was copied by
4406 : : * pullup_replace_vars earlier. Avoid scribbling on the original values of
4407 : : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
4408 : : */
4409 : :
4410 : : typedef struct
4411 : : {
4412 : : int varno;
4413 : : int sublevels_up;
4414 : : Relids subrelids;
4415 : : } substitute_phv_relids_context;
4416 : :
4417 : : static bool
2654 4418 : 227412 : substitute_phv_relids_walker(Node *node,
4419 : : substitute_phv_relids_context *context)
4420 : : {
6473 4421 [ + + ]: 227412 : if (node == NULL)
4422 : 92380 : return false;
6405 4423 [ + + ]: 135032 : if (IsA(node, PlaceHolderVar))
4424 : : {
4425 : 6604 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4426 : :
5155 4427 [ + + + + ]: 13184 : if (phv->phlevelsup == context->sublevels_up &&
4428 : 6580 : bms_is_member(context->varno, phv->phrels))
4429 : : {
6405 4430 : 9580 : phv->phrels = bms_union(phv->phrels,
4431 : 4790 : context->subrelids);
4432 : 4790 : phv->phrels = bms_del_member(phv->phrels,
4433 : : context->varno);
4434 : : /* Assert we haven't broken the PHV */
2654 4435 [ - + ]: 4790 : Assert(!bms_is_empty(phv->phrels));
4436 : : }
4437 : : /* fall through to examine children */
4438 : : }
5155 4439 [ + + ]: 135032 : if (IsA(node, Query))
4440 : : {
4441 : : /* Recurse into subselects */
4442 : : bool result;
4443 : :
4444 : 3748 : context->sublevels_up++;
4445 : 3748 : result = query_tree_walker((Query *) node,
4446 : : substitute_phv_relids_walker,
4447 : : context, 0);
4448 : 3748 : context->sublevels_up--;
4449 : 3748 : return result;
4450 : : }
4451 : : /* Shouldn't need to handle planner auxiliary nodes here */
6404 4452 [ - + ]: 131284 : Assert(!IsA(node, SpecialJoinInfo));
4453 [ - + ]: 131284 : Assert(!IsA(node, AppendRelInfo));
4454 [ - + ]: 131284 : Assert(!IsA(node, PlaceHolderInfo));
5661 4455 [ - + ]: 131284 : Assert(!IsA(node, MinMaxAggInfo));
4456 : :
523 peter@eisentraut.org 4457 : 131284 : return expression_tree_walker(node, substitute_phv_relids_walker, context);
4458 : : }
4459 : :
4460 : : static void
2654 tgl@sss.pgh.pa.us 4461 : 2095 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
4462 : : {
4463 : : substitute_phv_relids_context context;
4464 : :
6473 4465 : 2095 : context.varno = varno;
5155 4466 : 2095 : context.sublevels_up = 0;
6473 4467 : 2095 : context.subrelids = subrelids;
4468 : :
4469 : : /*
4470 : : * Must be prepared to start with a Query or a bare expression tree.
4471 : : */
4472 : 2095 : query_or_expression_tree_walker(node,
4473 : : substitute_phv_relids_walker,
4474 : : &context,
4475 : : 0);
8506 4476 : 2095 : }
4477 : :
4478 : : /*
4479 : : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
4480 : : *
4481 : : * When we pull up a subquery, any AppendRelInfo references to the subquery's
4482 : : * RT index have to be replaced by the substituted relid (and there had better
4483 : : * be only one). We also need to apply substitute_phv_relids to their
4484 : : * translated_vars lists, since those might contain PlaceHolderVars.
4485 : : *
4486 : : * We assume we may modify the AppendRelInfo nodes in-place.
4487 : : */
4488 : : static void
1230 4489 : 7051 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
4490 : : {
4491 : : ListCell *l;
7396 4492 : 7051 : int subvarno = -1;
4493 : :
4494 : : /*
4495 : : * We only want to extract the member relid once, but we mustn't fail
4496 : : * immediately if there are multiple members; it could be that none of the
4497 : : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
4498 : : * bms_singleton_member will complain if set is not singleton.
4499 : : */
1230 4500 [ + + + + : 16619 : foreach(l, root->append_rel_list)
+ + ]
4501 : : {
7396 4502 : 9568 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
4503 : :
4504 : : /* The parent_relid shouldn't ever be a pullup target */
4505 [ - + ]: 9568 : Assert(appinfo->parent_relid != varno);
4506 : :
4507 [ + + ]: 9568 : if (appinfo->child_relid == varno)
4508 : : {
4509 [ + - ]: 5121 : if (subvarno < 0)
4510 : 5121 : subvarno = bms_singleton_member(subrelids);
4511 : 5121 : appinfo->child_relid = subvarno;
4512 : : }
4513 : :
4514 : : /* Also fix up any PHVs in its translated vars */
1230 4515 [ + + ]: 9568 : if (root->glob->lastPHId != 0)
4516 : 135 : substitute_phv_relids((Node *) appinfo->translated_vars,
4517 : : varno, subrelids);
4518 : : }
7396 4519 : 7051 : }
4520 : :
4521 : : /*
4522 : : * get_relids_in_jointree: get set of RT indexes present in a jointree
4523 : : *
4524 : : * Base-relation relids are always included in the result.
4525 : : * If include_outer_joins is true, outer-join RT indexes are included.
4526 : : * If include_inner_joins is true, inner-join RT indexes are included.
4527 : : *
4528 : : * Note that for most purposes in the planner, outer joins are included
4529 : : * in standard relid sets. Setting include_inner_joins true is only
4530 : : * appropriate for special purposes during subquery flattening.
4531 : : */
4532 : : Relids
1191 4533 : 75321 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
4534 : : bool include_inner_joins)
4535 : : {
8487 4536 : 75321 : Relids result = NULL;
4537 : :
8506 4538 [ - + ]: 75321 : if (jtnode == NULL)
8506 tgl@sss.pgh.pa.us 4539 :UBC 0 : return result;
8506 tgl@sss.pgh.pa.us 4540 [ + + ]:CBC 75321 : if (IsA(jtnode, RangeTblRef))
4541 : : {
4542 : 38201 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4543 : :
8487 4544 : 38201 : result = bms_make_singleton(varno);
4545 : : }
8506 4546 [ + + ]: 37120 : else if (IsA(jtnode, FromExpr))
4547 : : {
4548 : 32432 : FromExpr *f = (FromExpr *) jtnode;
4549 : : ListCell *l;
4550 : :
4551 [ + - + + : 66416 : foreach(l, f->fromlist)
+ + ]
4552 : : {
8487 4553 : 33984 : result = bms_join(result,
6470 4554 : 33984 : get_relids_in_jointree(lfirst(l),
4555 : : include_outer_joins,
4556 : : include_inner_joins));
4557 : : }
4558 : : }
8506 4559 [ + - ]: 4688 : else if (IsA(jtnode, JoinExpr))
4560 : : {
4561 : 4688 : JoinExpr *j = (JoinExpr *) jtnode;
4562 : :
1191 4563 : 4688 : result = get_relids_in_jointree(j->larg,
4564 : : include_outer_joins,
4565 : : include_inner_joins);
6470 4566 : 4688 : result = bms_join(result,
4567 : : get_relids_in_jointree(j->rarg,
4568 : : include_outer_joins,
4569 : : include_inner_joins));
1191 4570 [ + + ]: 4688 : if (j->rtindex)
4571 : : {
4572 [ + + ]: 4429 : if (j->jointype == JOIN_INNER)
4573 : : {
4574 [ + + ]: 1821 : if (include_inner_joins)
4575 : 615 : result = bms_add_member(result, j->rtindex);
4576 : : }
4577 : : else
4578 : : {
4579 [ + + ]: 2608 : if (include_outer_joins)
4580 : 1681 : result = bms_add_member(result, j->rtindex);
4581 : : }
4582 : : }
4583 : : }
4584 : : else
8320 tgl@sss.pgh.pa.us 4585 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
4586 : : (int) nodeTag(jtnode));
8506 tgl@sss.pgh.pa.us 4587 :CBC 75321 : return result;
4588 : : }
4589 : :
4590 : : /*
4591 : : * get_relids_for_join: get set of base+OJ RT indexes making up a join
4592 : : */
4593 : : Relids
2653 4594 : 317 : get_relids_for_join(Query *query, int joinrelid)
4595 : : {
4596 : : Node *jtnode;
4597 : :
4598 : 317 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
4599 : : joinrelid);
8506 4600 [ - + ]: 317 : if (!jtnode)
8320 tgl@sss.pgh.pa.us 4601 [ # # ]:UBC 0 : elog(ERROR, "could not find join node %d", joinrelid);
1191 tgl@sss.pgh.pa.us 4602 :CBC 317 : return get_relids_in_jointree(jtnode, true, false);
4603 : : }
4604 : :
4605 : : /*
4606 : : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
4607 : : *
4608 : : * Returns NULL if not found
4609 : : */
4610 : : static Node *
8506 4611 : 1515 : find_jointree_node_for_rel(Node *jtnode, int relid)
4612 : : {
4613 [ - + ]: 1515 : if (jtnode == NULL)
8506 tgl@sss.pgh.pa.us 4614 :UBC 0 : return NULL;
8506 tgl@sss.pgh.pa.us 4615 [ + + ]:CBC 1515 : if (IsA(jtnode, RangeTblRef))
4616 : : {
4617 : 397 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4618 : :
4619 [ - + ]: 397 : if (relid == varno)
8506 tgl@sss.pgh.pa.us 4620 :UBC 0 : return jtnode;
4621 : : }
8506 tgl@sss.pgh.pa.us 4622 [ + + ]:CBC 1118 : else if (IsA(jtnode, FromExpr))
4623 : : {
4624 : 324 : FromExpr *f = (FromExpr *) jtnode;
4625 : : ListCell *l;
4626 : :
4627 [ + - + - : 339 : foreach(l, f->fromlist)
+ - ]
4628 : : {
4629 : 339 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
4630 [ + + ]: 339 : if (jtnode)
4631 : 324 : return jtnode;
4632 : : }
4633 : : }
4634 [ + - ]: 794 : else if (IsA(jtnode, JoinExpr))
4635 : : {
4636 : 794 : JoinExpr *j = (JoinExpr *) jtnode;
4637 : :
4638 [ + + ]: 794 : if (relid == j->rtindex)
4639 : 317 : return jtnode;
4640 : 477 : jtnode = find_jointree_node_for_rel(j->larg, relid);
4641 [ + + ]: 477 : if (jtnode)
4642 : 95 : return jtnode;
4643 : 382 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
4644 [ + - ]: 382 : if (jtnode)
4645 : 382 : return jtnode;
4646 : : }
4647 : : else
8320 tgl@sss.pgh.pa.us 4648 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
4649 : : (int) nodeTag(jtnode));
8506 tgl@sss.pgh.pa.us 4650 :CBC 397 : return NULL;
4651 : : }
4652 : :
4653 : : /*
4654 : : * get_nullingrels: collect info about which outer joins null which relations
4655 : : *
4656 : : * The result struct contains, for each leaf relation used in the query,
4657 : : * the set of relids of outer joins that potentially null that rel.
4658 : : */
4659 : : static nullingrel_info *
521 4660 : 1346 : get_nullingrels(Query *parse)
4661 : : {
4662 : 1346 : nullingrel_info *result = palloc_object(nullingrel_info);
4663 : :
4664 : 1346 : result->rtlength = list_length(parse->rtable);
4665 : 1346 : result->nullingrels = palloc0_array(Relids, result->rtlength + 1);
4666 : 1346 : get_nullingrels_recurse((Node *) parse->jointree, NULL, result);
4667 : 1346 : return result;
4668 : : }
4669 : :
4670 : : /*
4671 : : * Recursive guts of get_nullingrels().
4672 : : *
4673 : : * Note: at any recursion level, the passed-down upper_nullingrels must be
4674 : : * treated as a constant, but it can be stored directly into *info
4675 : : * if we're at leaf level. Upper recursion levels do not free their mutated
4676 : : * copies of the nullingrels, because those are probably referenced by
4677 : : * at least one leaf rel.
4678 : : */
4679 : : static void
4680 : 5540 : get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
4681 : : nullingrel_info *info)
4682 : : {
4683 [ - + ]: 5540 : if (jtnode == NULL)
521 tgl@sss.pgh.pa.us 4684 :UBC 0 : return;
521 tgl@sss.pgh.pa.us 4685 [ + + ]:CBC 5540 : if (IsA(jtnode, RangeTblRef))
4686 : : {
4687 : 2928 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4688 : :
4689 [ + - - + ]: 2928 : Assert(varno > 0 && varno <= info->rtlength);
4690 : 2928 : info->nullingrels[varno] = upper_nullingrels;
4691 : : }
4692 [ + + ]: 2612 : else if (IsA(jtnode, FromExpr))
4693 : : {
4694 : 1416 : FromExpr *f = (FromExpr *) jtnode;
4695 : : ListCell *l;
4696 : :
4697 [ + - + + : 3218 : foreach(l, f->fromlist)
+ + ]
4698 : : {
4699 : 1802 : get_nullingrels_recurse(lfirst(l), upper_nullingrels, info);
4700 : : }
4701 : : }
4702 [ + - ]: 1196 : else if (IsA(jtnode, JoinExpr))
4703 : : {
4704 : 1196 : JoinExpr *j = (JoinExpr *) jtnode;
4705 : : Relids local_nullingrels;
4706 : :
4707 [ + + + - : 1196 : switch (j->jointype)
- ]
4708 : : {
4709 : 385 : case JOIN_INNER:
4710 : 385 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4711 : 385 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4712 : 385 : break;
4713 : 806 : case JOIN_LEFT:
4714 : : case JOIN_SEMI:
4715 : : case JOIN_ANTI:
4716 : 806 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4717 : : j->rtindex);
4718 : 806 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4719 : 806 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4720 : 806 : break;
4721 : 5 : case JOIN_FULL:
4722 : 5 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4723 : : j->rtindex);
4724 : 5 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4725 : 5 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4726 : 5 : break;
521 tgl@sss.pgh.pa.us 4727 :UBC 0 : case JOIN_RIGHT:
4728 : 0 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4729 : : j->rtindex);
4730 : 0 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4731 : 0 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4732 : 0 : break;
4733 : 0 : default:
4734 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
4735 : : (int) j->jointype);
4736 : : break;
4737 : : }
4738 : : }
4739 : : else
4740 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
4741 : : (int) nodeTag(jtnode));
4742 : : }
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