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) 1996-2025, 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 : : List *sub_states; /* List of states for subtree components */
92 : : } reduce_outer_joins_pass1_state;
93 : :
94 : : typedef struct reduce_outer_joins_pass2_state
95 : : {
96 : : Relids inner_reduced; /* OJ relids reduced to plain inner joins */
97 : : List *partial_reduced; /* List of partially reduced FULL joins */
98 : : } reduce_outer_joins_pass2_state;
99 : :
100 : : typedef struct reduce_outer_joins_partial_state
101 : : {
102 : : int full_join_rti; /* RT index of a formerly-FULL join */
103 : : Relids unreduced_side; /* relids in its still-nullable side */
104 : : } reduce_outer_joins_partial_state;
105 : :
106 : : static Query *expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
107 : : RangeTblEntry *rte, int rt_index,
108 : : Relation relation);
109 : : static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
110 : : Relids *relids);
111 : : static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
112 : : Node **jtlink1, Relids available_rels1,
113 : : Node **jtlink2, Relids available_rels2);
114 : : static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
115 : : JoinExpr *lowest_outer_join,
116 : : AppendRelInfo *containing_appendrel);
117 : : static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
118 : : RangeTblEntry *rte,
119 : : JoinExpr *lowest_outer_join,
120 : : AppendRelInfo *containing_appendrel);
121 : : static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
122 : : RangeTblEntry *rte);
123 : : static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
124 : : int parentRTindex, Query *setOpQuery,
125 : : int childRToffset);
126 : : static void make_setop_translation_list(Query *query, int newvarno,
127 : : AppendRelInfo *appinfo);
128 : : static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
129 : : RangeTblEntry *rte,
130 : : JoinExpr *lowest_outer_join);
131 : : static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
132 : : RangeTblEntry *rte);
133 : : static bool is_simple_values(PlannerInfo *root, RangeTblEntry *rte);
134 : : static Node *pull_up_constant_function(PlannerInfo *root, Node *jtnode,
135 : : RangeTblEntry *rte,
136 : : AppendRelInfo *containing_appendrel);
137 : : static bool is_simple_union_all(Query *subquery);
138 : : static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery,
139 : : List *colTypes);
140 : : static bool is_safe_append_member(Query *subquery);
141 : : static bool jointree_contains_lateral_outer_refs(PlannerInfo *root,
142 : : Node *jtnode, bool restricted,
143 : : Relids safe_upper_varnos);
144 : : static void perform_pullup_replace_vars(PlannerInfo *root,
145 : : pullup_replace_vars_context *rvcontext,
146 : : AppendRelInfo *containing_appendrel);
147 : : static void replace_vars_in_jointree(Node *jtnode,
148 : : pullup_replace_vars_context *context);
149 : : static Node *pullup_replace_vars(Node *expr,
150 : : pullup_replace_vars_context *context);
151 : : static Node *pullup_replace_vars_callback(Var *var,
152 : : replace_rte_variables_context *context);
153 : : static Query *pullup_replace_vars_subquery(Query *query,
154 : : pullup_replace_vars_context *context);
155 : : static reduce_outer_joins_pass1_state *reduce_outer_joins_pass1(Node *jtnode);
156 : : static void reduce_outer_joins_pass2(Node *jtnode,
157 : : reduce_outer_joins_pass1_state *state1,
158 : : reduce_outer_joins_pass2_state *state2,
159 : : PlannerInfo *root,
160 : : Relids nonnullable_rels,
161 : : List *forced_null_vars);
162 : : static void report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
163 : : int rtindex, Relids relids);
164 : : static Node *remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
165 : : Node **parent_quals,
166 : : Relids *dropped_outer_joins);
167 : : static int get_result_relid(PlannerInfo *root, Node *jtnode);
168 : : static void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc);
169 : : static bool find_dependent_phvs(PlannerInfo *root, int varno);
170 : : static bool find_dependent_phvs_in_jointree(PlannerInfo *root,
171 : : Node *node, int varno);
172 : : static void substitute_phv_relids(Node *node,
173 : : int varno, Relids subrelids);
174 : : static void fix_append_rel_relids(PlannerInfo *root, int varno,
175 : : Relids subrelids);
176 : : static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
177 : : static nullingrel_info *get_nullingrels(Query *parse);
178 : : static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
179 : : nullingrel_info *info);
180 : :
181 : :
182 : : /*
183 : : * transform_MERGE_to_join
184 : : * Replace a MERGE's jointree to also include the target relation.
185 : : */
186 : : void
1360 alvherre@alvh.no-ip. 187 :CBC 272148 : transform_MERGE_to_join(Query *parse)
188 : : {
189 : : RangeTblEntry *joinrte;
190 : : JoinExpr *joinexpr;
191 : : bool have_action[NUM_MERGE_MATCH_KINDS];
192 : : JoinType jointype;
193 : : int joinrti;
194 : : List *vars;
195 : : RangeTblRef *rtr;
196 : : FromExpr *target;
197 : : Node *source;
198 : : int sourcerti;
199 : :
200 [ + + ]: 272148 : if (parse->commandType != CMD_MERGE)
201 : 271167 : return;
202 : :
203 : : /* XXX probably bogus */
204 : 981 : vars = NIL;
205 : :
206 : : /*
207 : : * Work out what kind of join is required. If there any WHEN NOT MATCHED
208 : : * BY SOURCE/TARGET actions, an outer join is required so that we process
209 : : * all unmatched tuples from the source and/or target relations.
210 : : * Otherwise, we can use an inner join.
211 : : */
627 dean.a.rasheed@gmail 212 : 981 : have_action[MERGE_WHEN_MATCHED] = false;
213 : 981 : have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = false;
214 : 981 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = false;
215 : :
216 [ + - + + : 3456 : foreach_node(MergeAction, action, parse->mergeActionList)
+ + ]
217 : : {
218 [ + + ]: 1494 : if (action->commandType != CMD_NOTHING)
219 : 1452 : have_action[action->matchKind] = true;
220 : : }
221 : :
222 [ + + ]: 981 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] &&
223 [ + + ]: 66 : have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
224 : 51 : jointype = JOIN_FULL;
225 [ + + ]: 930 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
226 : 15 : jointype = JOIN_LEFT;
227 [ + + ]: 915 : else if (have_action[MERGE_WHEN_NOT_MATCHED_BY_TARGET])
1360 alvherre@alvh.no-ip. 228 : 424 : jointype = JOIN_RIGHT;
229 : : else
230 : 491 : jointype = JOIN_INNER;
231 : :
232 : : /* Manufacture a join RTE to use. */
233 : 981 : joinrte = makeNode(RangeTblEntry);
234 : 981 : joinrte->rtekind = RTE_JOIN;
235 : 981 : joinrte->jointype = jointype;
236 : 981 : joinrte->joinmergedcols = 0;
237 : 981 : joinrte->joinaliasvars = vars;
238 : 981 : joinrte->joinleftcols = NIL; /* MERGE does not allow JOIN USING */
239 : 981 : joinrte->joinrightcols = NIL; /* ditto */
240 : 981 : joinrte->join_using_alias = NULL;
241 : :
242 : 981 : joinrte->alias = NULL;
243 : 981 : joinrte->eref = makeAlias("*MERGE*", NIL);
244 : 981 : joinrte->lateral = false;
245 : 981 : joinrte->inh = false;
246 : 981 : joinrte->inFromCl = true;
247 : :
248 : : /*
249 : : * Add completed RTE to pstate's range table list, so that we know its
250 : : * index.
251 : : */
252 : 981 : parse->rtable = lappend(parse->rtable, joinrte);
253 : 981 : joinrti = list_length(parse->rtable);
254 : :
255 : : /*
256 : : * Create a JOIN between the target and the source relation.
257 : : *
258 : : * Here the target is identified by parse->mergeTargetRelation. For a
259 : : * regular table, this will equal parse->resultRelation, but for a
260 : : * trigger-updatable view, it will be the expanded view subquery that we
261 : : * need to pull data from.
262 : : *
263 : : * The source relation is in parse->jointree->fromlist, but any quals in
264 : : * parse->jointree->quals are restrictions on the target relation (if the
265 : : * target relation is an auto-updatable view).
266 : : */
267 : : /* target rel, with any quals */
627 dean.a.rasheed@gmail 268 : 981 : rtr = makeNode(RangeTblRef);
269 : 981 : rtr->rtindex = parse->mergeTargetRelation;
440 270 : 981 : target = makeFromExpr(list_make1(rtr), parse->jointree->quals);
271 : :
272 : : /* source rel (expect exactly one -- see transformMergeStmt()) */
273 [ - + ]: 981 : Assert(list_length(parse->jointree->fromlist) == 1);
274 : 981 : source = linitial(parse->jointree->fromlist);
275 : :
276 : : /*
277 : : * index of source rel (expect either a RangeTblRef or a JoinExpr -- see
278 : : * transformFromClauseItem()).
279 : : */
280 [ + + ]: 981 : if (IsA(source, RangeTblRef))
281 : 939 : sourcerti = ((RangeTblRef *) source)->rtindex;
282 [ + - ]: 42 : else if (IsA(source, JoinExpr))
283 : 42 : sourcerti = ((JoinExpr *) source)->rtindex;
284 : : else
285 : : {
440 dean.a.rasheed@gmail 286 [ # # ]:UBC 0 : elog(ERROR, "unrecognized source node type: %d",
287 : : (int) nodeTag(source));
288 : : sourcerti = 0; /* keep compiler quiet */
289 : : }
290 : :
291 : : /* Join the source and target */
1360 alvherre@alvh.no-ip. 292 :CBC 981 : joinexpr = makeNode(JoinExpr);
293 : 981 : joinexpr->jointype = jointype;
294 : 981 : joinexpr->isNatural = false;
440 dean.a.rasheed@gmail 295 : 981 : joinexpr->larg = (Node *) target;
296 : 981 : joinexpr->rarg = source;
1360 alvherre@alvh.no-ip. 297 : 981 : joinexpr->usingClause = NIL;
298 : 981 : joinexpr->join_using_alias = NULL;
627 dean.a.rasheed@gmail 299 : 981 : joinexpr->quals = parse->mergeJoinCondition;
1360 alvherre@alvh.no-ip. 300 : 981 : joinexpr->alias = NULL;
301 : 981 : joinexpr->rtindex = joinrti;
302 : :
303 : : /* Make the new join be the sole entry in the query's jointree */
304 : 981 : parse->jointree->fromlist = list_make1(joinexpr);
305 : 981 : parse->jointree->quals = NULL;
306 : :
307 : : /*
308 : : * If necessary, mark parse->targetlist entries that refer to the target
309 : : * as nullable by the join. Normally the targetlist will be empty for a
310 : : * MERGE, but if the target is a trigger-updatable view, it will contain a
311 : : * whole-row Var referring to the expanded view query.
312 : : */
657 dean.a.rasheed@gmail 313 [ + + + + ]: 981 : if (parse->targetList != NIL &&
314 [ + + ]: 21 : (jointype == JOIN_RIGHT || jointype == JOIN_FULL))
315 : 21 : parse->targetList = (List *)
316 : 21 : add_nulling_relids((Node *) parse->targetList,
317 : 21 : bms_make_singleton(parse->mergeTargetRelation),
318 : 21 : bms_make_singleton(joinrti));
319 : :
320 : : /*
321 : : * If the source relation is on the outer side of the join, mark any
322 : : * source relation Vars in the join condition, actions, and RETURNING list
323 : : * as nullable by the join. These Vars will be added to the targetlist by
324 : : * preprocess_targetlist(), so it's important to mark them correctly here.
325 : : *
326 : : * It might seem that this is not necessary for Vars in the join
327 : : * condition, since it is inside the join, but it is also needed above the
328 : : * join (in the ModifyTable node) to distinguish between the MATCHED and
329 : : * NOT MATCHED BY SOURCE cases -- see ExecMergeMatched(). Note that this
330 : : * creates a modified copy of the join condition, for use above the join,
331 : : * without modifying the original join condition, inside the join.
332 : : */
440 333 [ + + + + ]: 981 : if (jointype == JOIN_LEFT || jointype == JOIN_FULL)
334 : : {
335 : 66 : parse->mergeJoinCondition =
336 : 66 : add_nulling_relids(parse->mergeJoinCondition,
337 : 66 : bms_make_singleton(sourcerti),
338 : 66 : bms_make_singleton(joinrti));
339 : :
340 [ + - + + : 315 : foreach_node(MergeAction, action, parse->mergeActionList)
+ + ]
341 : : {
342 : 183 : action->qual =
343 : 183 : add_nulling_relids(action->qual,
344 : 183 : bms_make_singleton(sourcerti),
345 : 183 : bms_make_singleton(joinrti));
346 : :
347 : 183 : action->targetList = (List *)
348 : 183 : add_nulling_relids((Node *) action->targetList,
349 : 183 : bms_make_singleton(sourcerti),
350 : 183 : bms_make_singleton(joinrti));
351 : : }
352 : :
353 : 66 : parse->returningList = (List *)
354 : 66 : add_nulling_relids((Node *) parse->returningList,
355 : 66 : bms_make_singleton(sourcerti),
356 : 66 : bms_make_singleton(joinrti));
357 : : }
358 : :
359 : : /*
360 : : * If there are any WHEN NOT MATCHED BY SOURCE actions, the executor will
361 : : * use the join condition to distinguish between MATCHED and NOT MATCHED
362 : : * BY SOURCE cases. Otherwise, it's no longer needed, and we set it to
363 : : * NULL, saving cycles during planning and execution.
364 : : *
365 : : * We need to be careful though: the executor evaluates this condition
366 : : * using the output of the join subplan node, which nulls the output from
367 : : * the source relation when the join condition doesn't match. That risks
368 : : * producing incorrect results when rechecking using a "non-strict" join
369 : : * condition, such as "src.col IS NOT DISTINCT FROM tgt.col". To guard
370 : : * against that, we add an additional "src IS NOT NULL" check to the join
371 : : * condition, so that it does the right thing when performing a recheck
372 : : * based on the output of the join subplan.
373 : : */
374 [ + + ]: 981 : if (have_action[MERGE_WHEN_NOT_MATCHED_BY_SOURCE])
375 : : {
376 : : Var *var;
377 : : NullTest *ntest;
378 : :
379 : : /* source wholerow Var (nullable by the new join) */
380 : 66 : var = makeWholeRowVar(rt_fetch(sourcerti, parse->rtable),
381 : : sourcerti, 0, false);
382 : 66 : var->varnullingrels = bms_make_singleton(joinrti);
383 : :
384 : : /* "src IS NOT NULL" check */
385 : 66 : ntest = makeNode(NullTest);
386 : 66 : ntest->arg = (Expr *) var;
387 : 66 : ntest->nulltesttype = IS_NOT_NULL;
388 : 66 : ntest->argisrow = false;
389 : 66 : ntest->location = -1;
390 : :
391 : : /* combine it with the original join condition */
392 : 66 : parse->mergeJoinCondition =
393 : 66 : (Node *) make_and_qual((Node *) ntest, parse->mergeJoinCondition);
394 : : }
395 : : else
396 : 915 : parse->mergeJoinCondition = NULL; /* join condition not needed */
397 : : }
398 : :
399 : : /*
400 : : * preprocess_relation_rtes
401 : : * Do the preprocessing work for any relation RTEs in the FROM clause.
402 : : *
403 : : * This scans the rangetable for relation RTEs and retrieves the necessary
404 : : * catalog information for each relation. Using this information, it clears
405 : : * the inh flag for any relation that has no children, collects not-null
406 : : * attribute numbers for any relation that has column not-null constraints, and
407 : : * expands virtual generated columns for any relation that contains them.
408 : : *
409 : : * Note that expanding virtual generated columns may cause the query tree to
410 : : * have new copies of rangetable entries. Therefore, we have to use list_nth
411 : : * instead of foreach when iterating over the query's rangetable.
412 : : *
413 : : * Returns a modified copy of the query tree, if any relations with virtual
414 : : * generated columns are present.
415 : : */
416 : : Query *
148 rguo@postgresql.org 417 :GNC 292895 : preprocess_relation_rtes(PlannerInfo *root)
418 : : {
419 : 292895 : Query *parse = root->parse;
420 : : int rtable_size;
421 : : int rt_index;
422 : :
423 : 292895 : rtable_size = list_length(parse->rtable);
424 : :
425 [ + + ]: 653543 : for (rt_index = 0; rt_index < rtable_size; rt_index++)
426 : : {
427 : 360648 : RangeTblEntry *rte = rt_fetch(rt_index + 1, parse->rtable);
428 : : Relation relation;
429 : :
430 : : /* We only care about relation RTEs. */
431 [ + + ]: 360648 : if (rte->rtekind != RTE_RELATION)
432 : 116755 : continue;
433 : :
434 : : /*
435 : : * We need not lock the relation since it was already locked by the
436 : : * rewriter.
437 : : */
438 : 243893 : relation = table_open(rte->relid, NoLock);
439 : :
440 : : /*
441 : : * Check to see if the relation actually has any children; if not,
442 : : * clear the inh flag so we can treat it as a plain base relation.
443 : : *
444 : : * Note: this could give a false-positive result, if the rel once had
445 : : * children but no longer does. We used to be able to clear rte->inh
446 : : * later on when we discovered that, but no more; we have to handle
447 : : * such cases as full-fledged inheritance.
448 : : */
449 [ + + ]: 243893 : if (rte->inh)
450 : 203160 : rte->inh = relation->rd_rel->relhassubclass;
451 : :
452 : : /*
453 : : * Check to see if the relation has any column not-null constraints;
454 : : * if so, retrieve the constraint information and store it in a
455 : : * relation OID based hash table.
456 : : */
457 : 243893 : get_relation_notnullatts(root, relation);
458 : :
459 : : /*
460 : : * Check to see if the relation has any virtual generated columns; if
461 : : * so, replace all Var nodes in the query that reference these columns
462 : : * with the generation expressions.
463 : : */
464 : 243893 : parse = expand_virtual_generated_columns(root, parse,
465 : : rte, rt_index + 1,
466 : : relation);
467 : :
468 : 243893 : table_close(relation, NoLock);
469 : : }
470 : :
471 : 292895 : return parse;
472 : : }
473 : :
474 : : /*
475 : : * expand_virtual_generated_columns
476 : : * Expand virtual generated columns for the given relation.
477 : : *
478 : : * This checks whether the given relation has any virtual generated columns,
479 : : * and if so, replaces all Var nodes in the query that reference those columns
480 : : * with their generation expressions.
481 : : *
482 : : * Returns a modified copy of the query tree if the relation contains virtual
483 : : * generated columns.
484 : : */
485 : : static Query *
486 : 243893 : expand_virtual_generated_columns(PlannerInfo *root, Query *parse,
487 : : RangeTblEntry *rte, int rt_index,
488 : : Relation relation)
489 : : {
490 : : TupleDesc tupdesc;
491 : :
492 : : /* Only normal relations can have virtual generated columns */
493 [ - + ]: 243893 : Assert(rte->rtekind == RTE_RELATION);
494 : :
495 : 243893 : tupdesc = RelationGetDescr(relation);
496 [ + + + + ]: 243893 : if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
497 : : {
498 : 551 : List *tlist = NIL;
499 : : pullup_replace_vars_context rvcontext;
500 : :
501 [ + + ]: 2099 : for (int i = 0; i < tupdesc->natts; i++)
502 : : {
503 : 1548 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
504 : : TargetEntry *tle;
505 : :
506 [ + + ]: 1548 : if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
507 : : {
508 : : Node *defexpr;
509 : :
510 : 722 : defexpr = build_generation_expression(relation, i + 1);
511 : 722 : ChangeVarNodes(defexpr, 1, rt_index, 0);
512 : :
513 : 722 : tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
514 : 722 : tlist = lappend(tlist, tle);
515 : : }
516 : : else
517 : : {
518 : : Var *var;
519 : :
520 : 826 : var = makeVar(rt_index,
521 : 826 : i + 1,
522 : : attr->atttypid,
523 : : attr->atttypmod,
524 : : attr->attcollation,
525 : : 0);
526 : :
527 : 826 : tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
528 : 826 : tlist = lappend(tlist, tle);
529 : : }
530 : : }
531 : :
532 [ - + ]: 551 : Assert(list_length(tlist) > 0);
533 [ - + ]: 551 : Assert(!rte->lateral);
534 : :
535 : : /*
536 : : * The relation's targetlist items are now in the appropriate form to
537 : : * insert into the query, except that we may need to wrap them in
538 : : * PlaceHolderVars. Set up required context data for
539 : : * pullup_replace_vars.
540 : : */
541 : 551 : rvcontext.root = root;
542 : 551 : rvcontext.targetlist = tlist;
543 : 551 : rvcontext.target_rte = rte;
544 : 551 : rvcontext.result_relation = parse->resultRelation;
545 : : /* won't need these values */
546 : 551 : rvcontext.relids = NULL;
547 : 551 : rvcontext.nullinfo = NULL;
548 : : /* pass NULL for outer_hasSubLinks */
549 : 551 : rvcontext.outer_hasSubLinks = NULL;
550 : 551 : rvcontext.varno = rt_index;
551 : : /* this flag will be set below, if needed */
552 : 551 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
553 : : /* initialize cache array with indexes 0 .. length(tlist) */
554 : 551 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
555 : : sizeof(Node *));
556 : :
557 : : /*
558 : : * If the query uses grouping sets, we need a PlaceHolderVar for each
559 : : * expression of the relation's targetlist items. (See comments in
560 : : * pull_up_simple_subquery().)
561 : : */
562 [ + + ]: 551 : if (parse->groupingSets)
563 : 6 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
564 : :
565 : : /*
566 : : * Apply pullup variable replacement throughout the query tree.
567 : : */
568 : 551 : parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
569 : : }
570 : :
571 : 243893 : return parse;
572 : : }
573 : :
574 : : /*
575 : : * replace_empty_jointree
576 : : * If the Query's jointree is empty, replace it with a dummy RTE_RESULT
577 : : * relation.
578 : : *
579 : : * By doing this, we can avoid a bunch of corner cases that formerly existed
580 : : * for SELECTs with omitted FROM clauses. An example is that a subquery
581 : : * with empty jointree previously could not be pulled up, because that would
582 : : * have resulted in an empty relid set, making the subquery not uniquely
583 : : * identifiable for join or PlaceHolderVar processing.
584 : : *
585 : : * Unlike most other functions in this file, this function doesn't recurse;
586 : : * we rely on other processing to invoke it on sub-queries at suitable times.
587 : : */
588 : : void
2515 tgl@sss.pgh.pa.us 589 :CBC 292895 : replace_empty_jointree(Query *parse)
590 : : {
591 : : RangeTblEntry *rte;
592 : : Index rti;
593 : : RangeTblRef *rtr;
594 : :
595 : : /* Nothing to do if jointree is already nonempty */
596 [ + + ]: 292895 : if (parse->jointree->fromlist != NIL)
597 : 194319 : return;
598 : :
599 : : /* We mustn't change it in the top level of a setop tree, either */
600 [ + + ]: 102101 : if (parse->setOperations)
601 : 3525 : return;
602 : :
603 : : /* Create suitable RTE */
604 : 98576 : rte = makeNode(RangeTblEntry);
605 : 98576 : rte->rtekind = RTE_RESULT;
606 : 98576 : rte->eref = makeAlias("*RESULT*", NIL);
607 : :
608 : : /* Add it to rangetable */
609 : 98576 : parse->rtable = lappend(parse->rtable, rte);
610 : 98576 : rti = list_length(parse->rtable);
611 : :
612 : : /* And jam a reference into the jointree */
613 : 98576 : rtr = makeNode(RangeTblRef);
614 : 98576 : rtr->rtindex = rti;
615 : 98576 : parse->jointree->fromlist = list_make1(rtr);
616 : : }
617 : :
618 : : /*
619 : : * pull_up_sublinks
620 : : * Attempt to pull up ANY and EXISTS SubLinks to be treated as
621 : : * semijoins or anti-semijoins.
622 : : *
623 : : * A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
624 : : * sub-SELECT up to become a rangetable entry and treating the implied
625 : : * comparisons as quals of a semijoin. However, this optimization *only*
626 : : * works at the top level of WHERE or a JOIN/ON clause, because we cannot
627 : : * distinguish whether the ANY ought to return FALSE or NULL in cases
628 : : * involving NULL inputs. Also, in an outer join's ON clause we can only
629 : : * do this if the sublink is degenerate (ie, references only the nullable
630 : : * side of the join). In that case it is legal to push the semijoin
631 : : * down into the nullable side of the join. If the sublink references any
632 : : * nonnullable-side variables then it would have to be evaluated as part
633 : : * of the outer join, which makes things way too complicated.
634 : : *
635 : : * Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
636 : : * by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
637 : : *
638 : : * This routine searches for such clauses and does the necessary parsetree
639 : : * transformations if any are found.
640 : : *
641 : : * This routine has to run before preprocess_expression(), so the quals
642 : : * clauses are not yet reduced to implicit-AND format, and are not guaranteed
643 : : * to be AND/OR-flat either. That means we need to recursively search through
644 : : * explicit AND clauses. We stop as soon as we hit a non-AND item.
645 : : */
646 : : void
6331 647 : 19854 : pull_up_sublinks(PlannerInfo *root)
648 : : {
649 : : Node *jtnode;
650 : : Relids relids;
651 : :
652 : : /* Begin recursion through the jointree */
6139 653 : 19854 : jtnode = pull_up_sublinks_jointree_recurse(root,
654 : 19854 : (Node *) root->parse->jointree,
655 : : &relids);
656 : :
657 : : /*
658 : : * root->parse->jointree must always be a FromExpr, so insert a dummy one
659 : : * if we got a bare RangeTblRef or JoinExpr out of the recursion.
660 : : */
661 [ + + ]: 19854 : if (IsA(jtnode, FromExpr))
662 : 15875 : root->parse->jointree = (FromExpr *) jtnode;
663 : : else
664 : 3979 : root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
6331 665 : 19854 : }
666 : :
667 : : /*
668 : : * Recurse through jointree nodes for pull_up_sublinks()
669 : : *
670 : : * In addition to returning the possibly-modified jointree node, we return
671 : : * a relids set of the contained rels into *relids.
672 : : */
673 : : static Node *
674 : 66411 : pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
675 : : Relids *relids)
676 : : {
677 : : /* Since this function recurses, it could be driven to stack overflow. */
1091 678 : 66411 : check_stack_depth();
679 : :
6331 680 [ - + ]: 66411 : if (jtnode == NULL)
681 : : {
6331 tgl@sss.pgh.pa.us 682 :UBC 0 : *relids = NULL;
683 : : }
6331 tgl@sss.pgh.pa.us 684 [ + + ]:CBC 66411 : else if (IsA(jtnode, RangeTblRef))
685 : : {
686 : 36077 : int varno = ((RangeTblRef *) jtnode)->rtindex;
687 : :
688 : 36077 : *relids = bms_make_singleton(varno);
689 : : /* jtnode is returned unmodified */
690 : : }
691 [ + + ]: 30334 : else if (IsA(jtnode, FromExpr))
692 : : {
693 : 19968 : FromExpr *f = (FromExpr *) jtnode;
694 : 19968 : List *newfromlist = NIL;
695 : 19968 : Relids frelids = NULL;
696 : : FromExpr *newf;
697 : : Node *jtlink;
698 : : ListCell *l;
699 : :
700 : : /* First, recurse to process children and collect their relids */
701 [ + - + + : 41702 : foreach(l, f->fromlist)
+ + ]
702 : : {
703 : : Node *newchild;
704 : : Relids childrelids;
705 : :
706 : 21734 : newchild = pull_up_sublinks_jointree_recurse(root,
707 : 21734 : lfirst(l),
708 : : &childrelids);
709 : 21734 : newfromlist = lappend(newfromlist, newchild);
710 : 21734 : frelids = bms_join(frelids, childrelids);
711 : : }
712 : : /* Build the replacement FromExpr; no quals yet */
6139 713 : 19968 : newf = makeFromExpr(newfromlist, NULL);
714 : : /* Set up a link representing the rebuilt jointree */
715 : 19968 : jtlink = (Node *) newf;
716 : : /* Now process qual --- all children are available for use */
5073 717 : 19968 : newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
718 : : &jtlink, frelids,
719 : : NULL, NULL);
720 : :
721 : : /*
722 : : * Note that the result will be either newf, or a stack of JoinExprs
723 : : * with newf at the base. We rely on subsequent optimization steps to
724 : : * flatten this and rearrange the joins as needed.
725 : : *
726 : : * Although we could include the pulled-up subqueries in the returned
727 : : * relids, there's no need since upper quals couldn't refer to their
728 : : * outputs anyway.
729 : : */
6331 730 : 19968 : *relids = frelids;
6139 731 : 19968 : jtnode = jtlink;
732 : : }
6331 733 [ + - ]: 10366 : else if (IsA(jtnode, JoinExpr))
734 : : {
735 : : JoinExpr *j;
736 : : Relids leftrelids;
737 : : Relids rightrelids;
738 : : Node *jtlink;
739 : :
740 : : /*
741 : : * Make a modifiable copy of join node, but don't bother copying its
742 : : * subnodes (yet).
743 : : */
7 michael@paquier.xyz 744 :GNC 10366 : j = palloc_object(JoinExpr);
6331 tgl@sss.pgh.pa.us 745 :CBC 10366 : memcpy(j, jtnode, sizeof(JoinExpr));
6139 746 : 10366 : jtlink = (Node *) j;
747 : :
748 : : /* Recurse to process children and collect their relids */
6331 749 : 10366 : j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
750 : : &leftrelids);
751 : 10366 : j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg,
752 : : &rightrelids);
753 : :
754 : : /*
755 : : * Now process qual, showing appropriate child relids as available,
756 : : * and attach any pulled-up jointree items at the right place. In the
757 : : * inner-join case we put new JoinExprs above the existing one (much
758 : : * as for a FromExpr-style join). In outer-join cases the new
759 : : * JoinExprs must go into the nullable side of the outer join. The
760 : : * point of the available_rels machinations is to ensure that we only
761 : : * pull up quals for which that's okay.
762 : : *
763 : : * We don't expect to see any pre-existing JOIN_SEMI, JOIN_ANTI,
764 : : * JOIN_RIGHT_SEMI, or JOIN_RIGHT_ANTI jointypes here.
765 : : */
766 [ + + + + : 10366 : switch (j->jointype)
- ]
767 : : {
768 : 4676 : case JOIN_INNER:
769 : 4676 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
770 : : &jtlink,
771 : : bms_union(leftrelids,
772 : : rightrelids),
773 : : NULL, NULL);
774 : 4676 : break;
775 : 5636 : case JOIN_LEFT:
776 : 5636 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
777 : : &j->rarg,
778 : : rightrelids,
779 : : NULL, NULL);
780 : 5636 : break;
781 : 6 : case JOIN_FULL:
782 : : /* can't do anything with full-join quals */
783 : 6 : break;
784 : 48 : case JOIN_RIGHT:
785 : 48 : j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
786 : : &j->larg,
787 : : leftrelids,
788 : : NULL, NULL);
789 : 48 : break;
6331 tgl@sss.pgh.pa.us 790 :UBC 0 : default:
791 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
792 : : (int) j->jointype);
793 : : break;
794 : : }
795 : :
796 : : /*
797 : : * Although we could include the pulled-up subqueries in the returned
798 : : * relids, there's no need since upper quals couldn't refer to their
799 : : * outputs anyway. But we *do* need to include the join's own rtindex
800 : : * because we haven't yet collapsed join alias variables, so upper
801 : : * levels would mistakenly think they couldn't use references to this
802 : : * join.
803 : : */
6139 tgl@sss.pgh.pa.us 804 :CBC 10366 : *relids = bms_join(leftrelids, rightrelids);
805 [ + - ]: 10366 : if (j->rtindex)
806 : 10366 : *relids = bms_add_member(*relids, j->rtindex);
807 : 10366 : jtnode = jtlink;
808 : : }
809 : : else
6331 tgl@sss.pgh.pa.us 810 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
811 : : (int) nodeTag(jtnode));
6331 tgl@sss.pgh.pa.us 812 :CBC 66411 : return jtnode;
813 : : }
814 : :
815 : : /*
816 : : * Recurse through top-level qual nodes for pull_up_sublinks()
817 : : *
818 : : * jtlink1 points to the link in the jointree where any new JoinExprs should
819 : : * be inserted if they reference available_rels1 (i.e., available_rels1
820 : : * denotes the relations present underneath jtlink1). Optionally, jtlink2 can
821 : : * point to a second link where new JoinExprs should be inserted if they
822 : : * reference available_rels2 (pass NULL for both those arguments if not used).
823 : : * Note that SubLinks referencing both sets of variables cannot be optimized.
824 : : * If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
825 : : * and/or jtlink2 in the order we encounter them. We rely on subsequent
826 : : * optimization to rearrange the stack if appropriate.
827 : : *
828 : : * Returns the replacement qual node, or NULL if the qual should be removed.
829 : : */
830 : : static Node *
831 : 62319 : pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
832 : : Node **jtlink1, Relids available_rels1,
833 : : Node **jtlink2, Relids available_rels2)
834 : : {
8367 835 [ + + ]: 62319 : if (node == NULL)
836 : 3918 : return NULL;
837 [ + + ]: 58401 : if (IsA(node, SubLink))
838 : : {
8171 bruce@momjian.us 839 : 2896 : SubLink *sublink = (SubLink *) node;
840 : : JoinExpr *j;
841 : : Relids child_rels;
842 : :
843 : : /* Is it a convertible ANY or EXISTS clause? */
6334 tgl@sss.pgh.pa.us 844 [ + + ]: 2896 : if (sublink->subLinkType == ANY_SUBLINK)
845 : : {
846 : : ScalarArrayOpExpr *saop;
847 : :
257 akorotkov@postgresql 848 [ + + ]: 2405 : if ((saop = convert_VALUES_to_ANY(root,
849 : : sublink->testexpr,
850 : 2405 : (Query *) sublink->subselect)) != NULL)
851 : :
852 : : /*
853 : : * The VALUES sequence was simplified. Nothing more to do
854 : : * here.
855 : : */
856 : 42 : return (Node *) saop;
857 : :
5073 tgl@sss.pgh.pa.us 858 [ + + ]: 2363 : if ((j = convert_ANY_sublink_to_join(root, sublink,
859 : : available_rels1)) != NULL)
860 : : {
861 : : /* Yes; insert the new join node into the join tree */
862 : 2310 : j->larg = *jtlink1;
863 : 2310 : *jtlink1 = (Node *) j;
864 : : /* Recursively process pulled-up jointree nodes */
865 : 2310 : j->rarg = pull_up_sublinks_jointree_recurse(root,
866 : : j->rarg,
867 : : &child_rels);
868 : :
869 : : /*
870 : : * Now recursively process the pulled-up quals. Any inserted
871 : : * joins can get stacked onto either j->larg or j->rarg,
872 : : * depending on which rels they reference.
873 : : */
874 : 2310 : j->quals = pull_up_sublinks_qual_recurse(root,
875 : : j->quals,
876 : : &j->larg,
877 : : available_rels1,
878 : : &j->rarg,
879 : : child_rels);
880 : : /* Return NULL representing constant TRUE */
881 : 2310 : return NULL;
882 : : }
883 [ + + - + ]: 56 : if (available_rels2 != NULL &&
884 : 3 : (j = convert_ANY_sublink_to_join(root, sublink,
885 : : available_rels2)) != NULL)
886 : : {
887 : : /* Yes; insert the new join node into the join tree */
5073 tgl@sss.pgh.pa.us 888 :UBC 0 : j->larg = *jtlink2;
889 : 0 : *jtlink2 = (Node *) j;
890 : : /* Recursively process pulled-up jointree nodes */
5343 891 : 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
892 : : j->rarg,
893 : : &child_rels);
894 : :
895 : : /*
896 : : * Now recursively process the pulled-up quals. Any inserted
897 : : * joins can get stacked onto either j->larg or j->rarg,
898 : : * depending on which rels they reference.
899 : : */
900 : 0 : j->quals = pull_up_sublinks_qual_recurse(root,
901 : : j->quals,
902 : : &j->larg,
903 : : available_rels2,
904 : : &j->rarg,
905 : : child_rels);
906 : : /* Return NULL representing constant TRUE */
6139 907 : 0 : return NULL;
908 : : }
909 : : }
6334 tgl@sss.pgh.pa.us 910 [ + + ]:CBC 491 : else if (sublink->subLinkType == EXISTS_SUBLINK)
911 : : {
5073 912 [ + + ]: 461 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, false,
913 : : available_rels1)) != NULL)
914 : : {
915 : : /* Yes; insert the new join node into the join tree */
916 : 377 : j->larg = *jtlink1;
917 : 377 : *jtlink1 = (Node *) j;
918 : : /* Recursively process pulled-up jointree nodes */
5343 919 : 377 : j->rarg = pull_up_sublinks_jointree_recurse(root,
920 : : j->rarg,
921 : : &child_rels);
922 : :
923 : : /*
924 : : * Now recursively process the pulled-up quals. Any inserted
925 : : * joins can get stacked onto either j->larg or j->rarg,
926 : : * depending on which rels they reference.
927 : : */
928 : 377 : j->quals = pull_up_sublinks_qual_recurse(root,
929 : : j->quals,
930 : : &j->larg,
931 : : available_rels1,
932 : : &j->rarg,
933 : : child_rels);
934 : : /* Return NULL representing constant TRUE */
5073 935 : 377 : return NULL;
936 : : }
937 [ + + + - ]: 100 : if (available_rels2 != NULL &&
938 : 16 : (j = convert_EXISTS_sublink_to_join(root, sublink, false,
939 : : available_rels2)) != NULL)
940 : : {
941 : : /* Yes; insert the new join node into the join tree */
942 : 16 : j->larg = *jtlink2;
943 : 16 : *jtlink2 = (Node *) j;
944 : : /* Recursively process pulled-up jointree nodes */
945 : 16 : j->rarg = pull_up_sublinks_jointree_recurse(root,
946 : : j->rarg,
947 : : &child_rels);
948 : :
949 : : /*
950 : : * Now recursively process the pulled-up quals. Any inserted
951 : : * joins can get stacked onto either j->larg or j->rarg,
952 : : * depending on which rels they reference.
953 : : */
954 : 16 : j->quals = pull_up_sublinks_qual_recurse(root,
955 : : j->quals,
956 : : &j->larg,
957 : : available_rels2,
958 : : &j->rarg,
959 : : child_rels);
960 : : /* Return NULL representing constant TRUE */
6139 961 : 16 : return NULL;
962 : : }
963 : : }
964 : : /* Else return it unmodified */
6334 965 : 151 : return node;
966 : : }
2514 967 [ + + ]: 55505 : if (is_notclause(node))
968 : : {
969 : : /* If the immediate argument of NOT is EXISTS, try to convert */
6334 970 : 3786 : SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
971 : : JoinExpr *j;
972 : : Relids child_rels;
973 : :
974 [ + - + + ]: 3786 : if (sublink && IsA(sublink, SubLink))
975 : : {
976 [ + + ]: 1443 : if (sublink->subLinkType == EXISTS_SUBLINK)
977 : : {
5073 978 [ + + ]: 1395 : if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
979 : : available_rels1)) != NULL)
980 : : {
981 : : /* Yes; insert the new join node into the join tree */
982 : 1388 : j->larg = *jtlink1;
983 : 1388 : *jtlink1 = (Node *) j;
984 : : /* Recursively process pulled-up jointree nodes */
985 : 1388 : j->rarg = pull_up_sublinks_jointree_recurse(root,
986 : : j->rarg,
987 : : &child_rels);
988 : :
989 : : /*
990 : : * Now recursively process the pulled-up quals. Because
991 : : * we are underneath a NOT, we can't pull up sublinks that
992 : : * reference the left-hand stuff, but it's still okay to
993 : : * pull up sublinks referencing j->rarg.
994 : : */
995 : 1388 : j->quals = pull_up_sublinks_qual_recurse(root,
996 : : j->quals,
997 : : &j->rarg,
998 : : child_rels,
999 : : NULL, NULL);
1000 : : /* Return NULL representing constant TRUE */
1001 : 1388 : return NULL;
1002 : : }
1003 [ - + - - ]: 7 : if (available_rels2 != NULL &&
5073 tgl@sss.pgh.pa.us 1004 :UBC 0 : (j = convert_EXISTS_sublink_to_join(root, sublink, true,
1005 : : available_rels2)) != NULL)
1006 : : {
1007 : : /* Yes; insert the new join node into the join tree */
1008 : 0 : j->larg = *jtlink2;
1009 : 0 : *jtlink2 = (Node *) j;
1010 : : /* Recursively process pulled-up jointree nodes */
5343 1011 : 0 : j->rarg = pull_up_sublinks_jointree_recurse(root,
1012 : : j->rarg,
1013 : : &child_rels);
1014 : :
1015 : : /*
1016 : : * Now recursively process the pulled-up quals. Because
1017 : : * we are underneath a NOT, we can't pull up sublinks that
1018 : : * reference the left-hand stuff, but it's still okay to
1019 : : * pull up sublinks referencing j->rarg.
1020 : : */
1021 : 0 : j->quals = pull_up_sublinks_qual_recurse(root,
1022 : : j->quals,
1023 : : &j->rarg,
1024 : : child_rels,
1025 : : NULL, NULL);
1026 : : /* Return NULL representing constant TRUE */
6139 1027 : 0 : return NULL;
1028 : : }
1029 : : }
1030 : : }
1031 : : /* Else return it unmodified */
6334 tgl@sss.pgh.pa.us 1032 :CBC 2398 : return node;
1033 : : }
2514 1034 [ + + ]: 51719 : if (is_andclause(node))
1035 : : {
1036 : : /* Recurse into AND clause */
8171 bruce@momjian.us 1037 : 9699 : List *newclauses = NIL;
1038 : : ListCell *l;
1039 : :
7875 neilc@samurai.com 1040 [ + - + + : 37599 : foreach(l, ((BoolExpr *) node)->args)
+ + ]
1041 : : {
1042 : 27900 : Node *oldclause = (Node *) lfirst(l);
1043 : : Node *newclause;
1044 : :
6139 tgl@sss.pgh.pa.us 1045 : 27900 : newclause = pull_up_sublinks_qual_recurse(root,
1046 : : oldclause,
1047 : : jtlink1,
1048 : : available_rels1,
1049 : : jtlink2,
1050 : : available_rels2);
1051 [ + + ]: 27900 : if (newclause)
1052 : 25004 : newclauses = lappend(newclauses, newclause);
1053 : : }
1054 : : /* We might have got back fewer clauses than we started with */
1055 [ + + ]: 9699 : if (newclauses == NIL)
1056 : 63 : return NULL;
1057 [ + + ]: 9636 : else if (list_length(newclauses) == 1)
1058 : 582 : return (Node *) linitial(newclauses);
1059 : : else
1060 : 9054 : return (Node *) make_andclause(newclauses);
1061 : : }
1062 : : /* Stop if not an AND */
8367 1063 : 42020 : return node;
1064 : : }
1065 : :
1066 : : /*
1067 : : * preprocess_function_rtes
1068 : : * Constant-simplify any FUNCTION RTEs in the FROM clause, and then
1069 : : * attempt to "inline" any that can be converted to simple subqueries.
1070 : : *
1071 : : * If an RTE_FUNCTION rtable entry invokes a set-returning SQL function that
1072 : : * contains just a simple SELECT, we can convert the rtable entry to an
1073 : : * RTE_SUBQUERY entry exposing the SELECT directly. Other sorts of functions
1074 : : * are also inline-able if they have a support function that can generate
1075 : : * the replacement sub-Query. This is especially useful if the subquery can
1076 : : * then be "pulled up" for further optimization, but we do it even if not,
1077 : : * to reduce executor overhead.
1078 : : *
1079 : : * This has to be done before we have started to do any optimization of
1080 : : * subqueries, else any such steps wouldn't get applied to subqueries
1081 : : * obtained via inlining. However, we do it after pull_up_sublinks
1082 : : * so that we can inline any functions used in SubLink subselects.
1083 : : *
1084 : : * The reason for applying const-simplification at this stage is that
1085 : : * (a) we'd need to do it anyway to inline a SRF, and (b) by doing it now,
1086 : : * we can be sure that pull_up_constant_function() will see constants
1087 : : * if there are constants to be seen. This approach also guarantees
1088 : : * that every FUNCTION RTE has been const-simplified, allowing planner.c's
1089 : : * preprocess_expression() to skip doing it again.
1090 : : *
1091 : : * Like most of the planner, this feels free to scribble on its input data
1092 : : * structure.
1093 : : */
1094 : : void
2330 1095 : 291092 : preprocess_function_rtes(PlannerInfo *root)
1096 : : {
1097 : : ListCell *rt;
1098 : :
6483 1099 [ + - + + : 752583 : foreach(rt, root->parse->rtable)
+ + ]
1100 : : {
1101 : 461494 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
1102 : :
1103 [ + + ]: 461494 : if (rte->rtekind == RTE_FUNCTION)
1104 : : {
1105 : : Query *funcquery;
1106 : :
1107 : : /* Apply const-simplification */
2330 1108 : 25427 : rte->functions = (List *)
1109 : 25427 : eval_const_expressions(root, (Node *) rte->functions);
1110 : :
1111 : : /* Check safety of expansion, and expand if possible */
25 tgl@sss.pgh.pa.us 1112 :GNC 25427 : funcquery = inline_function_in_from(root, rte);
6483 tgl@sss.pgh.pa.us 1113 [ + + ]:CBC 25424 : if (funcquery)
1114 : : {
1115 : : /* Successful expansion, convert the RTE to a subquery */
1116 : 123 : rte->rtekind = RTE_SUBQUERY;
1117 : 123 : rte->subquery = funcquery;
2647 1118 : 123 : rte->security_barrier = false;
1119 : :
1120 : : /*
1121 : : * Clear fields that should not be set in a subquery RTE.
1122 : : * However, we leave rte->functions filled in for the moment,
1123 : : * in case makeWholeRowVar needs to consult it. We'll clear
1124 : : * it in setrefs.c (see add_rte_to_flat_rtable) so that this
1125 : : * abuse of the data structure doesn't escape the planner.
1126 : : */
1127 : 123 : rte->funcordinality = false;
1128 : : }
1129 : : }
1130 : : }
6483 1131 : 291089 : }
1132 : :
1133 : : /*
1134 : : * pull_up_subqueries
1135 : : * Look for subqueries in the rangetable that can be pulled up into
1136 : : * the parent query. If the subquery has no special features like
1137 : : * grouping/aggregation then we can merge it into the parent's jointree.
1138 : : * Also, subqueries that are simple UNION ALL structures can be
1139 : : * converted into "append relations".
1140 : : */
1141 : : void
3934 1142 : 291089 : pull_up_subqueries(PlannerInfo *root)
1143 : : {
1144 : : /* Top level of jointree must always be a FromExpr */
1145 [ - + ]: 291089 : Assert(IsA(root->parse->jointree, FromExpr));
1146 : : /* Recursion starts with no containing join nor appendrel */
1147 : 582175 : root->parse->jointree = (FromExpr *)
1148 : 291089 : pull_up_subqueries_recurse(root, (Node *) root->parse->jointree,
1149 : : NULL, NULL);
1150 : : /* We should still have a FromExpr */
1151 [ - + ]: 291086 : Assert(IsA(root->parse->jointree, FromExpr));
4875 1152 : 291086 : }
1153 : :
1154 : : /*
1155 : : * pull_up_subqueries_recurse
1156 : : * Recursive guts of pull_up_subqueries.
1157 : : *
1158 : : * This recursively processes the jointree and returns a modified jointree.
1159 : : *
1160 : : * If this jointree node is within either side of an outer join, then
1161 : : * lowest_outer_join references the lowest such JoinExpr node; otherwise
1162 : : * it is NULL. We use this to constrain the effects of LATERAL subqueries.
1163 : : *
1164 : : * If we are looking at a member subquery of an append relation,
1165 : : * containing_appendrel describes that relation; else it is NULL.
1166 : : * This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
1167 : : * items, and puts some additional restrictions on what can be pulled up.
1168 : : *
1169 : : * A tricky aspect of this code is that if we pull up a subquery we have
1170 : : * to replace Vars that reference the subquery's outputs throughout the
1171 : : * parent query, including quals attached to jointree nodes above the one
1172 : : * we are currently processing! We handle this by being careful to maintain
1173 : : * validity of the jointree structure while recursing, in the following sense:
1174 : : * whenever we recurse, all qual expressions in the tree must be reachable
1175 : : * from the top level, in case the recursive call needs to modify them.
1176 : : *
1177 : : * Notice also that we can't turn pullup_replace_vars loose on the whole
1178 : : * jointree, because it'd return a mutated copy of the tree; we have to
1179 : : * invoke it just on the quals, instead. This behavior is what makes it
1180 : : * reasonable to pass lowest_outer_join as a pointer rather than some
1181 : : * more-indirect way of identifying the lowest OJ. Likewise, we don't
1182 : : * replace append_rel_list members but only their substructure, so the
1183 : : * containing_appendrel reference is safe to use.
1184 : : */
1185 : : static Node *
1186 : 720160 : pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
1187 : : JoinExpr *lowest_outer_join,
1188 : : AppendRelInfo *containing_appendrel)
1189 : : {
1190 : : /* Since this function recurses, it could be driven to stack overflow. */
1091 1191 : 720160 : check_stack_depth();
1192 : : /* Also, since it's a bit expensive, let's check for query cancel. */
1193 [ - + ]: 720160 : CHECK_FOR_INTERRUPTS();
1194 : :
3934 1195 [ - + ]: 720160 : Assert(jtnode != NULL);
8367 1196 [ + + ]: 720160 : if (IsA(jtnode, RangeTblRef))
1197 : : {
1198 : 372753 : int varno = ((RangeTblRef *) jtnode)->rtindex;
7257 1199 : 372753 : RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
1200 : :
1201 : : /*
1202 : : * Is this a subquery RTE, and if so, is the subquery simple enough to
1203 : : * pull up?
1204 : : *
1205 : : * If we are looking at an append-relation member, we can't pull it up
1206 : : * unless is_safe_append_member says so.
1207 : : */
7891 1208 [ + + + + ]: 405877 : if (rte->rtekind == RTE_SUBQUERY &&
1791 1209 [ + + ]: 55120 : is_simple_subquery(root, rte->subquery, rte, lowest_outer_join) &&
6077 1210 [ + + ]: 6356 : (containing_appendrel == NULL ||
1211 : 6356 : is_safe_append_member(rte->subquery)))
7257 1212 : 18944 : return pull_up_simple_subquery(root, jtnode, rte,
1213 : : lowest_outer_join,
1214 : : containing_appendrel);
1215 : :
1216 : : /*
1217 : : * Alternatively, is it a simple UNION ALL subquery? If so, flatten
1218 : : * into an "append relation".
1219 : : *
1220 : : * It's safe to do this regardless of whether this query is itself an
1221 : : * appendrel member. (If you're thinking we should try to flatten the
1222 : : * two levels of appendrel together, you're right; but we handle that
1223 : : * in set_append_rel_pathlist, not here.)
1224 : : */
1225 [ + + + + ]: 367989 : if (rte->rtekind == RTE_SUBQUERY &&
1226 : 14180 : is_simple_union_all(rte->subquery))
1227 : 2464 : return pull_up_simple_union_all(root, jtnode, rte);
1228 : :
1229 : : /*
1230 : : * Or perhaps it's a simple VALUES RTE?
1231 : : *
1232 : : * We don't allow VALUES pullup below an outer join nor into an
1233 : : * appendrel (such cases are impossible anyway at the moment).
1234 : : */
3934 1235 [ + + + - ]: 351345 : if (rte->rtekind == RTE_VALUES &&
1236 [ + - ]: 6539 : lowest_outer_join == NULL &&
1237 [ + + ]: 6539 : containing_appendrel == NULL &&
2515 1238 : 6539 : is_simple_values(root, rte))
3934 1239 : 2297 : return pull_up_simple_values(root, jtnode, rte);
1240 : :
1241 : : /*
1242 : : * Or perhaps it's a FUNCTION RTE that we could inline?
1243 : : */
2330 1244 [ + + ]: 349048 : if (rte->rtekind == RTE_FUNCTION)
1245 : 25301 : return pull_up_constant_function(root, jtnode, rte,
1246 : : containing_appendrel);
1247 : :
1248 : : /* Otherwise, do nothing at this node. */
1249 : : }
8367 1250 [ + + ]: 347407 : else if (IsA(jtnode, FromExpr))
1251 : : {
1252 : 296058 : FromExpr *f = (FromExpr *) jtnode;
1253 : : ListCell *l;
1254 : :
6077 1255 [ - + ]: 296058 : Assert(containing_appendrel == NULL);
1256 : : /* Recursively transform all the child nodes */
8367 1257 [ + + + + : 614142 : foreach(l, f->fromlist)
+ + ]
1258 : : {
4875 1259 : 318087 : lfirst(l) = pull_up_subqueries_recurse(root, lfirst(l),
1260 : : lowest_outer_join,
1261 : : NULL);
1262 : : }
1263 : : }
8367 1264 [ + - ]: 51349 : else if (IsA(jtnode, JoinExpr))
1265 : : {
1266 : 51349 : JoinExpr *j = (JoinExpr *) jtnode;
1267 : :
6077 1268 [ - + ]: 51349 : Assert(containing_appendrel == NULL);
1269 : : /* Recurse, being careful to tell myself when inside outer join */
8367 1270 [ + + + + : 51349 : switch (j->jointype)
- ]
1271 : : {
1272 : 22998 : case JOIN_INNER:
4875 1273 : 22998 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1274 : : lowest_outer_join,
1275 : : NULL);
1276 : 22998 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1277 : : lowest_outer_join,
1278 : : NULL);
8367 1279 : 22998 : break;
1280 : 27193 : case JOIN_LEFT:
1281 : : case JOIN_SEMI:
1282 : : case JOIN_ANTI:
4875 1283 : 27193 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1284 : : j,
1285 : : NULL);
1286 : 27193 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1287 : : j,
1288 : : NULL);
8367 1289 : 27193 : break;
1290 : 548 : case JOIN_FULL:
4875 1291 : 548 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1292 : : j,
1293 : : NULL);
1294 : 548 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1295 : : j,
1296 : : NULL);
8367 1297 : 548 : break;
1298 : 610 : case JOIN_RIGHT:
4875 1299 : 610 : j->larg = pull_up_subqueries_recurse(root, j->larg,
1300 : : j,
1301 : : NULL);
1302 : 610 : j->rarg = pull_up_subqueries_recurse(root, j->rarg,
1303 : : j,
1304 : : NULL);
8367 1305 : 610 : break;
8367 tgl@sss.pgh.pa.us 1306 :UBC 0 : default:
8181 1307 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
1308 : : (int) j->jointype);
1309 : : break;
1310 : : }
1311 : : }
1312 : : else
1313 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
1314 : : (int) nodeTag(jtnode));
8367 tgl@sss.pgh.pa.us 1315 :CBC 671151 : return jtnode;
1316 : : }
1317 : :
1318 : : /*
1319 : : * pull_up_simple_subquery
1320 : : * Attempt to pull up a single simple subquery.
1321 : : *
1322 : : * jtnode is a RangeTblRef that has been tentatively identified as a simple
1323 : : * subquery by pull_up_subqueries. We return the replacement jointree node,
1324 : : * or jtnode itself if we determine that the subquery can't be pulled up
1325 : : * after all.
1326 : : *
1327 : : * rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
1328 : : * as for pull_up_subqueries_recurse.
1329 : : */
1330 : : static Node *
7257 1331 : 18944 : pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
1332 : : JoinExpr *lowest_outer_join,
1333 : : AppendRelInfo *containing_appendrel)
1334 : : {
1335 : 18944 : Query *parse = root->parse;
1336 : 18944 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1337 : : Query *subquery;
1338 : : PlannerInfo *subroot;
1339 : : int rtoffset;
1340 : : pullup_replace_vars_context rvcontext;
1341 : : ListCell *lc;
1342 : :
1343 : : /*
1344 : : * Make a modifiable copy of the subquery to hack on, so that the RTE will
1345 : : * be left unchanged in case we decide below that we can't pull it up
1346 : : * after all.
1347 : : */
1348 : 18944 : subquery = copyObject(rte->subquery);
1349 : :
1350 : : /*
1351 : : * Create a PlannerInfo data structure for this subquery.
1352 : : *
1353 : : * NOTE: the next few steps should match the first processing in
1354 : : * subquery_planner(). Can we refactor to avoid code duplication, or
1355 : : * would that just make things uglier?
1356 : : */
1357 : 18944 : subroot = makeNode(PlannerInfo);
1358 : 18944 : subroot->parse = subquery;
6876 1359 : 18944 : subroot->glob = root->glob;
1360 : 18944 : subroot->query_level = root->query_level;
71 rhaas@postgresql.org 1361 :GNC 18944 : subroot->plan_name = root->plan_name;
6283 tgl@sss.pgh.pa.us 1362 :CBC 18944 : subroot->parent_root = root->parent_root;
4851 1363 : 18944 : subroot->plan_params = NIL;
3781 1364 : 18944 : subroot->outer_params = NULL;
6906 1365 : 18944 : subroot->planner_cxt = CurrentMemoryContext;
6876 1366 : 18944 : subroot->init_plans = NIL;
6283 1367 : 18944 : subroot->cte_plan_ids = NIL;
4200 1368 : 18944 : subroot->multiexpr_params = NIL;
1052 1369 : 18944 : subroot->join_domains = NIL;
6483 1370 : 18944 : subroot->eq_classes = NIL;
2341 drowley@postgresql.o 1371 : 18944 : subroot->ec_merging_done = false;
1052 tgl@sss.pgh.pa.us 1372 : 18944 : subroot->last_rinfo_serial = 0;
1722 1373 : 18944 : subroot->all_result_relids = NULL;
1374 : 18944 : subroot->leaf_result_relids = NULL;
7257 1375 : 18944 : subroot->append_rel_list = NIL;
1722 1376 : 18944 : subroot->row_identity_vars = NIL;
5896 1377 : 18944 : subroot->rowMarks = NIL;
3572 1378 : 18944 : memset(subroot->upper_rels, 0, sizeof(subroot->upper_rels));
3565 1379 : 18944 : memset(subroot->upper_targets, 0, sizeof(subroot->upper_targets));
1064 1380 : 18944 : subroot->processed_groupClause = NIL;
1381 : 18944 : subroot->processed_distinctClause = NIL;
3572 1382 : 18944 : subroot->processed_tlist = NIL;
1722 1383 : 18944 : subroot->update_colnos = NIL;
3572 1384 : 18944 : subroot->grouping_map = NULL;
1385 : 18944 : subroot->minmax_aggs = NIL;
3255 1386 : 18944 : subroot->qual_security_level = 0;
1218 1387 : 18944 : subroot->placeholdersFrozen = false;
6283 1388 : 18944 : subroot->hasRecursion = false;
119 rhaas@postgresql.org 1389 :GNC 18944 : subroot->assumeReplanning = false;
6283 tgl@sss.pgh.pa.us 1390 :CBC 18944 : subroot->wt_param_id = -1;
3572 1391 : 18944 : subroot->non_recursive_path = NULL;
1392 : : /* We don't currently need a top JoinDomain for the subroot */
1393 : :
1394 : : /* No CTEs to worry about */
6283 1395 [ - + ]: 18944 : Assert(subquery->cteList == NIL);
1396 : :
1397 : : /*
1398 : : * Scan the rangetable for relation RTEs and retrieve the necessary
1399 : : * catalog information for each relation. Using this information, clear
1400 : : * the inh flag for any relation that has no children, collect not-null
1401 : : * attribute numbers for any relation that has column not-null
1402 : : * constraints, and expand virtual generated columns for any relation that
1403 : : * contains them.
1404 : : */
148 rguo@postgresql.org 1405 :GNC 18944 : subquery = subroot->parse = preprocess_relation_rtes(subroot);
1406 : :
1407 : : /*
1408 : : * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
1409 : : * that we don't need so many special cases to deal with that situation.
1410 : : */
2515 tgl@sss.pgh.pa.us 1411 :CBC 18944 : replace_empty_jointree(subquery);
1412 : :
1413 : : /*
1414 : : * Pull up any SubLinks within the subquery's quals, so that we don't
1415 : : * leave unoptimized SubLinks behind.
1416 : : */
7257 1417 [ + + ]: 18944 : if (subquery->hasSubLinks)
6331 1418 : 1214 : pull_up_sublinks(subroot);
1419 : :
1420 : : /*
1421 : : * Similarly, preprocess its function RTEs to inline any set-returning
1422 : : * functions in its rangetable.
1423 : : */
2330 1424 : 18944 : preprocess_function_rtes(subroot);
1425 : :
1426 : : /*
1427 : : * Recursively pull up the subquery's subqueries, so that
1428 : : * pull_up_subqueries' processing is complete for its jointree and
1429 : : * rangetable.
1430 : : *
1431 : : * Note: it's okay that the subquery's recursion starts with NULL for
1432 : : * containing-join info, even if we are within an outer join in the upper
1433 : : * query; the lower query starts with a clean slate for outer-join
1434 : : * semantics. Likewise, we needn't pass down appendrel state.
1435 : : */
3934 1436 : 18944 : pull_up_subqueries(subroot);
1437 : :
1438 : : /*
1439 : : * Now we must recheck whether the subquery is still simple enough to pull
1440 : : * up. If not, abandon processing it.
1441 : : *
1442 : : * We don't really need to recheck all the conditions involved, but it's
1443 : : * easier just to keep this "if" looking the same as the one in
1444 : : * pull_up_subqueries_recurse.
1445 : : */
1791 1446 [ + + + + ]: 22134 : if (is_simple_subquery(root, subquery, rte, lowest_outer_join) &&
6077 1447 [ + + ]: 3304 : (containing_appendrel == NULL || is_safe_append_member(subquery)))
1448 : : {
1449 : : /* good to go */
1450 : : }
1451 : : else
1452 : : {
1453 : : /*
1454 : : * Give up, return unmodified RangeTblRef.
1455 : : *
1456 : : * Note: The work we just did will be redone when the subquery gets
1457 : : * planned on its own. Perhaps we could avoid that by storing the
1458 : : * modified subquery back into the rangetable, but I'm not gonna risk
1459 : : * it now.
1460 : : */
7257 1461 : 120 : return jtnode;
1462 : : }
1463 : :
1464 : : /*
1465 : : * We must flatten any join alias Vars in the subquery's targetlist,
1466 : : * because pulling up the subquery's subqueries might have changed their
1467 : : * expansions into arbitrary expressions, which could affect
1468 : : * pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
1469 : : * are needed for tlist entries. (Likely it'd be better to do
1470 : : * flatten_join_alias_vars on the whole query tree at some earlier stage,
1471 : : * maybe even in the rewriter; but for now let's just fix this case here.)
1472 : : */
4408 1473 : 18824 : subquery->targetList = (List *)
1052 1474 : 18824 : flatten_join_alias_vars(subroot, subroot->parse,
1475 : 18824 : (Node *) subquery->targetList);
1476 : :
1477 : : /*
1478 : : * Adjust level-0 varnos in subquery so that we can append its rangetable
1479 : : * to upper query's. We have to fix the subquery's append_rel_list as
1480 : : * well.
1481 : : */
7257 1482 : 18824 : rtoffset = list_length(parse->rtable);
1483 : 18824 : OffsetVarNodes((Node *) subquery, rtoffset, 0);
1484 : 18824 : OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);
1485 : :
1486 : : /*
1487 : : * Upper-level vars in subquery are now one level closer to their parent
1488 : : * than before.
1489 : : */
1490 : 18824 : IncrementVarSublevelsUp((Node *) subquery, -1, 1);
1491 : 18824 : IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);
1492 : :
1493 : : /*
1494 : : * The subquery's targetlist items are now in the appropriate form to
1495 : : * insert into the top query, except that we may need to wrap them in
1496 : : * PlaceHolderVars. Set up required context data for pullup_replace_vars.
1497 : : * (Note that we should include the subquery's inner joins in relids,
1498 : : * since it may include join alias vars referencing them.)
1499 : : */
5950 1500 : 18824 : rvcontext.root = root;
1501 : 18824 : rvcontext.targetlist = subquery->targetList;
1502 : 18824 : rvcontext.target_rte = rte;
295 rguo@postgresql.org 1503 : 18824 : rvcontext.result_relation = 0;
4505 tgl@sss.pgh.pa.us 1504 [ + + ]: 18824 : if (rte->lateral)
1505 : : {
1506 : 583 : rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
1507 : : true, true);
382 1508 : 583 : rvcontext.nullinfo = get_nullingrels(parse);
1509 : : }
1510 : : else /* won't need these values */
1511 : : {
4505 1512 : 18241 : rvcontext.relids = NULL;
382 1513 : 18241 : rvcontext.nullinfo = NULL;
1514 : : }
5950 1515 : 18824 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
1516 : 18824 : rvcontext.varno = varno;
1517 : : /* this flag will be set below, if needed */
279 rguo@postgresql.org 1518 : 18824 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
1519 : : /* initialize cache array with indexes 0 .. length(tlist) */
5950 tgl@sss.pgh.pa.us 1520 : 18824 : rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
1521 : : sizeof(Node *));
1522 : :
1523 : : /*
1524 : : * If the parent query uses grouping sets, we need a PlaceHolderVar for
1525 : : * each expression of the subquery's targetlist items. This ensures that
1526 : : * expressions retain their separate identity so that they will match
1527 : : * grouping set columns when appropriate. (It'd be sufficient to wrap
1528 : : * values used in grouping set columns, and do so only in non-aggregated
1529 : : * portions of the tlist and havingQual, but that would require a lot of
1530 : : * infrastructure that pullup_replace_vars hasn't currently got.)
1531 : : */
2896 1532 [ + + ]: 18824 : if (parse->groupingSets)
279 rguo@postgresql.org 1533 : 166 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
1534 : :
1535 : : /*
1536 : : * Replace all of the top query's references to the subquery's outputs
1537 : : * with copies of the adjusted subtlist items, being careful not to
1538 : : * replace any of the jointree structure.
1539 : : */
2330 tgl@sss.pgh.pa.us 1540 : 18824 : perform_pullup_replace_vars(root, &rvcontext,
1541 : : containing_appendrel);
1542 : :
1543 : : /*
1544 : : * If the subquery had a LATERAL marker, propagate that to any of its
1545 : : * child RTEs that could possibly now contain lateral cross-references.
1546 : : * The children might or might not contain any actual lateral
1547 : : * cross-references, but we have to mark the pulled-up child RTEs so that
1548 : : * later planner stages will check for such.
1549 : : */
4875 1550 [ + + ]: 18821 : if (rte->lateral)
1551 : : {
1552 [ + - + + : 1364 : foreach(lc, subquery->rtable)
+ + ]
1553 : : {
1554 : 781 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
1555 : :
1556 [ + + + - ]: 781 : switch (child_rte->rtekind)
1557 : : {
3798 1558 : 348 : case RTE_RELATION:
1559 [ + + ]: 348 : if (child_rte->tablesample)
1560 : 18 : child_rte->lateral = true;
1561 : 348 : break;
4875 1562 : 140 : case RTE_SUBQUERY:
1563 : : case RTE_FUNCTION:
1564 : : case RTE_VALUES:
1565 : : case RTE_TABLEFUNC:
1566 : 140 : child_rte->lateral = true;
1567 : 140 : break;
1568 : 293 : case RTE_JOIN:
1569 : : case RTE_CTE:
1570 : : case RTE_NAMEDTUPLESTORE:
1571 : : case RTE_RESULT:
1572 : : case RTE_GROUP:
1573 : : /* these can't contain any lateral references */
1574 : 293 : break;
1575 : : }
1576 : : }
1577 : : }
1578 : :
1579 : : /*
1580 : : * Now append the adjusted rtable entries and their perminfos to upper
1581 : : * query. (We hold off until after fixing the upper rtable entries; no
1582 : : * point in running that code on the subquery ones too.)
1583 : : */
1107 alvherre@alvh.no-ip. 1584 : 18821 : CombineRangeTables(&parse->rtable, &parse->rteperminfos,
1585 : : subquery->rtable, subquery->rteperminfos);
1586 : :
1587 : : /*
1588 : : * Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
1589 : : * adjusted the marker rtindexes, so just concat the lists.)
1590 : : */
7257 tgl@sss.pgh.pa.us 1591 : 18821 : parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
1592 : :
1593 : : /*
1594 : : * We also have to fix the relid sets of any PlaceHolderVar nodes in the
1595 : : * parent query. (This could perhaps be done by pullup_replace_vars(),
1596 : : * but it seems cleaner to use two passes.) Note in particular that any
1597 : : * PlaceHolderVar nodes just created by pullup_replace_vars() will be
1598 : : * adjusted, so having created them with the subquery's varno is correct.
1599 : : *
1600 : : * Likewise, relids appearing in AppendRelInfo nodes have to be fixed. We
1601 : : * already checked that this won't require introducing multiple subrelids
1602 : : * into the single-slot AppendRelInfo structs.
1603 : : */
1091 1604 [ + + + + ]: 18821 : if (root->glob->lastPHId != 0 || root->append_rel_list)
1605 : : {
1606 : : Relids subrelids;
1607 : :
1052 1608 : 4160 : subrelids = get_relids_in_jointree((Node *) subquery->jointree,
1609 : : true, false);
1091 1610 [ + + ]: 4160 : if (root->glob->lastPHId != 0)
1611 : 997 : substitute_phv_relids((Node *) parse, varno, subrelids);
1612 : 4160 : fix_append_rel_relids(root, varno, subrelids);
1613 : : }
1614 : :
1615 : : /*
1616 : : * And now add subquery's AppendRelInfos to our list.
1617 : : */
7257 1618 : 37642 : root->append_rel_list = list_concat(root->append_rel_list,
1619 : 18821 : subroot->append_rel_list);
1620 : :
1621 : : /*
1622 : : * We don't have to do the equivalent bookkeeping for outer-join info,
1623 : : * because that hasn't been set up yet. placeholder_list likewise.
1624 : : */
6334 1625 [ - + ]: 18821 : Assert(root->join_info_list == NIL);
1626 [ - + ]: 18821 : Assert(subroot->join_info_list == NIL);
6265 1627 [ - + ]: 18821 : Assert(root->placeholder_list == NIL);
1628 [ - + ]: 18821 : Assert(subroot->placeholder_list == NIL);
1629 : :
1630 : : /*
1631 : : * We no longer need the RTE's copy of the subquery's query tree. Getting
1632 : : * rid of it saves nothing in particular so far as this level of query is
1633 : : * concerned; but if this query level is in turn pulled up into a parent,
1634 : : * we'd waste cycles copying the now-unused query tree.
1635 : : */
1625 1636 : 18821 : rte->subquery = NULL;
1637 : :
1638 : : /*
1639 : : * Miscellaneous housekeeping.
1640 : : *
1641 : : * Although replace_rte_variables() faithfully updated parse->hasSubLinks
1642 : : * if it copied any SubLinks out of the subquery's targetlist, we still
1643 : : * could have SubLinks added to the query in the expressions of FUNCTION
1644 : : * and VALUES RTEs copied up from the subquery. So it's necessary to copy
1645 : : * subquery->hasSubLinks anyway. Perhaps this can be improved someday.
1646 : : */
7257 1647 : 18821 : parse->hasSubLinks |= subquery->hasSubLinks;
1648 : :
1649 : : /* If subquery had any RLS conditions, now main query does too */
3324 1650 : 18821 : parse->hasRowSecurity |= subquery->hasRowSecurity;
1651 : :
1652 : : /*
1653 : : * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or
1654 : : * hasTargetSRFs, so no work needed on those flags
1655 : : */
1656 : :
1657 : : /*
1658 : : * Return the adjusted subquery jointree to replace the RangeTblRef entry
1659 : : * in parent's jointree; or, if the FromExpr is degenerate, just return
1660 : : * its single member.
1661 : : */
2515 1662 [ - + ]: 18821 : Assert(IsA(subquery->jointree, FromExpr));
1663 [ - + ]: 18821 : Assert(subquery->jointree->fromlist != NIL);
1664 [ + + + + ]: 34706 : if (subquery->jointree->quals == NULL &&
1665 : 15885 : list_length(subquery->jointree->fromlist) == 1)
1666 : 15726 : return (Node *) linitial(subquery->jointree->fromlist);
1667 : :
7257 1668 : 3095 : return (Node *) subquery->jointree;
1669 : : }
1670 : :
1671 : : /*
1672 : : * pull_up_simple_union_all
1673 : : * Pull up a single simple UNION ALL subquery.
1674 : : *
1675 : : * jtnode is a RangeTblRef that has been identified as a simple UNION ALL
1676 : : * subquery by pull_up_subqueries. We pull up the leaf subqueries and
1677 : : * build an "append relation" for the union set. The result value is just
1678 : : * jtnode, since we don't actually need to change the query jointree.
1679 : : */
1680 : : static Node *
1681 : 2464 : pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
1682 : : {
1683 : 2464 : int varno = ((RangeTblRef *) jtnode)->rtindex;
1684 : 2464 : Query *subquery = rte->subquery;
4876 1685 : 2464 : int rtoffset = list_length(root->parse->rtable);
1686 : : List *rtable;
1687 : :
1688 : : /*
1689 : : * Make a modifiable copy of the subquery's rtable, so we can adjust
1690 : : * upper-level Vars in it. There are no such Vars in the setOperations
1691 : : * tree proper, so fixing the rtable should be sufficient.
1692 : : */
1693 : 2464 : rtable = copyObject(subquery->rtable);
1694 : :
1695 : : /*
1696 : : * Upper-level vars in subquery are now one level closer to their parent
1697 : : * than before. We don't have to worry about offsetting varnos, though,
1698 : : * because the UNION leaf queries can't cross-reference each other.
1699 : : */
6334 heikki.linnakangas@i 1700 : 2464 : IncrementVarSublevelsUp_rtable(rtable, -1, 1);
1701 : :
1702 : : /*
1703 : : * If the UNION ALL subquery had a LATERAL marker, propagate that to all
1704 : : * its children. The individual children might or might not contain any
1705 : : * actual lateral cross-references, but we have to mark the pulled-up
1706 : : * child RTEs so that later planner stages will check for such.
1707 : : */
4876 tgl@sss.pgh.pa.us 1708 [ + + ]: 2464 : if (rte->lateral)
1709 : : {
1710 : : ListCell *rt;
1711 : :
1712 [ + - + + : 99 : foreach(rt, rtable)
+ + ]
1713 : : {
1714 : 66 : RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(rt);
1715 : :
1716 [ - + ]: 66 : Assert(child_rte->rtekind == RTE_SUBQUERY);
1717 : 66 : child_rte->lateral = true;
1718 : : }
1719 : : }
1720 : :
1721 : : /*
1722 : : * Append child RTEs (and their perminfos) to parent rtable.
1723 : : */
1107 alvherre@alvh.no-ip. 1724 : 2464 : CombineRangeTables(&root->parse->rtable, &root->parse->rteperminfos,
1725 : : rtable, subquery->rteperminfos);
1726 : :
1727 : : /*
1728 : : * Recursively scan the subquery's setOperations tree and add
1729 : : * AppendRelInfo nodes for leaf subqueries to the parent's
1730 : : * append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
1731 : : */
7257 tgl@sss.pgh.pa.us 1732 [ - + ]: 2464 : Assert(subquery->setOperations);
6334 heikki.linnakangas@i 1733 : 2464 : pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery,
1734 : : rtoffset);
1735 : :
1736 : : /*
1737 : : * Mark the parent as an append relation.
1738 : : */
7257 tgl@sss.pgh.pa.us 1739 : 2464 : rte->inh = true;
1740 : :
1741 : 2464 : return jtnode;
1742 : : }
1743 : :
1744 : : /*
1745 : : * pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
1746 : : *
1747 : : * Build an AppendRelInfo for each leaf query in the setop tree, and then
1748 : : * apply pull_up_subqueries to the leaf query.
1749 : : *
1750 : : * Note that setOpQuery is the Query containing the setOp node, whose tlist
1751 : : * contains references to all the setop output columns. When called from
1752 : : * pull_up_simple_union_all, this is *not* the same as root->parse, which is
1753 : : * the parent Query we are pulling up into.
1754 : : *
1755 : : * parentRTindex is the appendrel parent's index in root->parse->rtable.
1756 : : *
1757 : : * The child RTEs have already been copied to the parent. childRToffset
1758 : : * tells us where in the parent's range table they were copied. When called
1759 : : * from flatten_simple_union_all, childRToffset is 0 since the child RTEs
1760 : : * were already in root->parse->rtable and no RT index adjustment is needed.
1761 : : */
1762 : : static void
1763 : 13711 : pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
1764 : : Query *setOpQuery, int childRToffset)
1765 : : {
1766 [ + + ]: 13711 : if (IsA(setOp, RangeTblRef))
1767 : : {
1768 : 8286 : RangeTblRef *rtr = (RangeTblRef *) setOp;
1769 : : int childRTindex;
1770 : : AppendRelInfo *appinfo;
1771 : :
1772 : : /*
1773 : : * Calculate the index in the parent's range table
1774 : : */
6334 heikki.linnakangas@i 1775 : 8286 : childRTindex = childRToffset + rtr->rtindex;
1776 : :
1777 : : /*
1778 : : * Build a suitable AppendRelInfo, and attach to parent's list.
1779 : : */
7257 tgl@sss.pgh.pa.us 1780 : 8286 : appinfo = makeNode(AppendRelInfo);
1781 : 8286 : appinfo->parent_relid = parentRTindex;
1782 : 8286 : appinfo->child_relid = childRTindex;
1783 : 8286 : appinfo->parent_reltype = InvalidOid;
1784 : 8286 : appinfo->child_reltype = InvalidOid;
2207 1785 : 8286 : make_setop_translation_list(setOpQuery, childRTindex, appinfo);
7257 1786 : 8286 : appinfo->parent_reloid = InvalidOid;
1787 : 8286 : root->append_rel_list = lappend(root->append_rel_list, appinfo);
1788 : :
1789 : : /*
1790 : : * Recursively apply pull_up_subqueries to the new child RTE. (We
1791 : : * must build the AppendRelInfo first, because this will modify it;
1792 : : * indeed, that's the only part of the upper query where Vars
1793 : : * referencing childRTindex can exist at this point.)
1794 : : *
1795 : : * Note that we can pass NULL for containing-join info even if we're
1796 : : * actually under an outer join, because the child's expressions
1797 : : * aren't going to propagate up to the join. Also, we ignore the
1798 : : * possibility that pull_up_subqueries_recurse() returns a different
1799 : : * jointree node than what we pass it; if it does, the important thing
1800 : : * is that it replaced the child relid in the AppendRelInfo node.
1801 : : */
1802 : 8286 : rtr = makeNode(RangeTblRef);
1803 : 8286 : rtr->rtindex = childRTindex;
4875 1804 : 8286 : (void) pull_up_subqueries_recurse(root, (Node *) rtr,
1805 : : NULL, appinfo);
1806 : : }
7257 1807 [ + - ]: 5425 : else if (IsA(setOp, SetOperationStmt))
1808 : : {
1809 : 5425 : SetOperationStmt *op = (SetOperationStmt *) setOp;
1810 : :
1811 : : /* Recurse to reach leaf queries */
6334 heikki.linnakangas@i 1812 : 5425 : pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery,
1813 : : childRToffset);
1814 : 5425 : pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery,
1815 : : childRToffset);
1816 : : }
1817 : : else
1818 : : {
7257 tgl@sss.pgh.pa.us 1819 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
1820 : : (int) nodeTag(setOp));
1821 : : }
7257 tgl@sss.pgh.pa.us 1822 :CBC 13711 : }
1823 : :
1824 : : /*
1825 : : * make_setop_translation_list
1826 : : * Build the list of translations from parent Vars to child Vars for
1827 : : * a UNION ALL member. (At this point it's just a simple list of
1828 : : * referencing Vars, but if we succeed in pulling up the member
1829 : : * subquery, the Vars will get replaced by pulled-up expressions.)
1830 : : * Also create the rather trivial reverse-translation array.
1831 : : */
1832 : : static void
1554 1833 : 8286 : make_setop_translation_list(Query *query, int newvarno,
1834 : : AppendRelInfo *appinfo)
1835 : : {
7257 1836 : 8286 : List *vars = NIL;
1837 : : AttrNumber *pcolnos;
1838 : : ListCell *l;
1839 : :
1840 : : /* Initialize reverse-translation array with all entries zero */
1841 : : /* (entries for resjunk columns will stay that way) */
2207 1842 : 8286 : appinfo->num_child_cols = list_length(query->targetList);
1843 : 8286 : appinfo->parent_colnos = pcolnos =
1844 : 8286 : (AttrNumber *) palloc0(appinfo->num_child_cols * sizeof(AttrNumber));
1845 : :
7257 1846 [ + + + + : 37801 : foreach(l, query->targetList)
+ + ]
1847 : : {
1848 : 29515 : TargetEntry *tle = (TargetEntry *) lfirst(l);
1849 : :
1850 [ - + ]: 29515 : if (tle->resjunk)
7257 tgl@sss.pgh.pa.us 1851 :UBC 0 : continue;
1852 : :
5591 peter_e@gmx.net 1853 :CBC 29515 : vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
2207 tgl@sss.pgh.pa.us 1854 : 29515 : pcolnos[tle->resno - 1] = tle->resno;
1855 : : }
1856 : :
1857 : 8286 : appinfo->translated_vars = vars;
7257 1858 : 8286 : }
1859 : :
1860 : : /*
1861 : : * is_simple_subquery
1862 : : * Check a subquery in the range table to see if it's simple enough
1863 : : * to pull up into the parent query.
1864 : : *
1865 : : * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
1866 : : * (Note subquery is not necessarily equal to rte->subquery; it could be a
1867 : : * processed copy of that.)
1868 : : * lowest_outer_join is the lowest outer join above the subquery, or NULL.
1869 : : */
1870 : : static bool
1791 1871 : 52068 : is_simple_subquery(PlannerInfo *root, Query *subquery, RangeTblEntry *rte,
1872 : : JoinExpr *lowest_outer_join)
1873 : : {
1874 : : /*
1875 : : * Let's just make sure it's a valid subselect ...
1876 : : */
8367 1877 [ + - ]: 52068 : if (!IsA(subquery, Query) ||
3259 1878 [ - + ]: 52068 : subquery->commandType != CMD_SELECT)
8181 tgl@sss.pgh.pa.us 1879 [ # # ]:UBC 0 : elog(ERROR, "subquery is bogus");
1880 : :
1881 : : /*
1882 : : * Can't currently pull up a query with setops (unless it's simple UNION
1883 : : * ALL, which is handled by a different code path). Maybe after querytree
1884 : : * redesign...
1885 : : */
8367 tgl@sss.pgh.pa.us 1886 [ + + ]:CBC 52068 : if (subquery->setOperations)
1887 : 2908 : return false;
1888 : :
1889 : : /*
1890 : : * Can't pull up a subquery involving grouping, aggregation, SRFs,
1891 : : * sorting, limiting, or WITH. (XXX WITH could possibly be allowed later)
1892 : : *
1893 : : * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
1894 : : * clauses, because pullup would cause the locking to occur semantically
1895 : : * higher than it should. Implicit FOR UPDATE/SHARE is okay because in
1896 : : * that case the locking was originally declared in the upper query
1897 : : * anyway.
1898 : : */
1899 [ + + ]: 49160 : if (subquery->hasAggs ||
6198 1900 [ + + ]: 48255 : subquery->hasWindowFuncs ||
3382 1901 [ + + ]: 48062 : subquery->hasTargetSRFs ||
8367 1902 [ + + ]: 45916 : subquery->groupClause ||
3868 andres@anarazel.de 1903 [ + + ]: 45873 : subquery->groupingSets ||
8367 tgl@sss.pgh.pa.us 1904 [ + - ]: 45855 : subquery->havingQual ||
1905 [ + + ]: 45855 : subquery->sortClause ||
1906 [ + + ]: 45416 : subquery->distinctClause ||
1907 [ + + ]: 44970 : subquery->limitOffset ||
6283 1908 [ + + ]: 44745 : subquery->limitCount ||
5894 1909 [ + + ]: 44590 : subquery->hasForUpdate ||
6283 1910 [ + + ]: 41521 : subquery->cteList)
8367 1911 : 7723 : return false;
1912 : :
1913 : : /*
1914 : : * Don't pull up if the RTE represents a security-barrier view; we
1915 : : * couldn't prevent information leakage once the RTE's Vars are scattered
1916 : : * about in the upper query.
1917 : : */
4875 1918 [ + + ]: 41437 : if (rte->security_barrier)
4880 1919 : 350 : return false;
1920 : :
1921 : : /*
1922 : : * If the subquery is LATERAL, check for pullup restrictions from that.
1923 : : */
4503 1924 [ + + ]: 41087 : if (rte->lateral)
1925 : : {
1926 : : bool restricted;
1927 : : Relids safe_upper_varnos;
1928 : :
1929 : : /*
1930 : : * The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
1931 : : * references to rels outside a higher outer join (including the case
1932 : : * where the outer join is within the subquery itself). In such a
1933 : : * case, pulling up would result in a situation where we need to
1934 : : * postpone quals from below an outer join to above it, which is
1935 : : * probably completely wrong and in any case is a complication that
1936 : : * doesn't seem worth addressing at the moment.
1937 : : */
1938 [ + + ]: 1214 : if (lowest_outer_join != NULL)
1939 : : {
1940 : 690 : restricted = true;
1941 : 690 : safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
1942 : : true, true);
1943 : : }
1944 : : else
1945 : : {
1946 : 524 : restricted = false;
1947 : 524 : safe_upper_varnos = NULL; /* doesn't matter */
1948 : : }
1949 : :
1791 1950 [ + + ]: 1214 : if (jointree_contains_lateral_outer_refs(root,
1951 : 1214 : (Node *) subquery->jointree,
1952 : : restricted, safe_upper_varnos))
4875 1953 : 12 : return false;
1954 : :
1955 : : /*
1956 : : * If there's an outer join above the LATERAL subquery, also disallow
1957 : : * pullup if the subquery's targetlist has any references to rels
1958 : : * outside the outer join, since these might get pulled into quals
1959 : : * above the subquery (but in or below the outer join) and then lead
1960 : : * to qual-postponement issues similar to the case checked for above.
1961 : : * (We wouldn't need to prevent pullup if no such references appear in
1962 : : * outer-query quals, but we don't have enough info here to check
1963 : : * that. Also, maybe this restriction could be removed if we forced
1964 : : * such refs to be wrapped in PlaceHolderVars, even when they're below
1965 : : * the nearest outer join? But it's a pretty hokey usage, so not
1966 : : * clear this is worth sweating over.)
1967 : : *
1968 : : * If you change this, see also the comments about lateral references
1969 : : * in pullup_replace_vars_callback().
1970 : : */
4503 1971 [ + + ]: 1202 : if (lowest_outer_join != NULL)
1972 : : {
1791 1973 : 690 : Relids lvarnos = pull_varnos_of_level(root,
1974 : 690 : (Node *) subquery->targetList,
1975 : : 1);
1976 : :
4503 1977 [ + + ]: 690 : if (!bms_is_subset(lvarnos, safe_upper_varnos))
1978 : 6 : return false;
1979 : : }
1980 : : }
1981 : :
1982 : : /*
1983 : : * Don't pull up a subquery that has any volatile functions in its
1984 : : * targetlist. Otherwise we might introduce multiple evaluations of these
1985 : : * functions, if they get copied to multiple places in the upper query,
1986 : : * leading to surprising results. (Note: the PlaceHolderVar mechanism
1987 : : * doesn't quite guarantee single evaluation; else we could pull up anyway
1988 : : * and just wrap such items in PlaceHolderVars ...)
1989 : : */
7060 1990 [ + + ]: 41069 : if (contain_volatile_functions((Node *) subquery->targetList))
8367 1991 : 135 : return false;
1992 : :
3934 1993 : 40934 : return true;
1994 : : }
1995 : :
1996 : : /*
1997 : : * pull_up_simple_values
1998 : : * Pull up a single simple VALUES RTE.
1999 : : *
2000 : : * jtnode is a RangeTblRef that has been identified as a simple VALUES RTE
2001 : : * by pull_up_subqueries. We always return a RangeTblRef representing a
2002 : : * RESULT RTE to replace it (all failure cases should have been detected by
2003 : : * is_simple_values()). Actually, what we return is just jtnode, because
2004 : : * we replace the VALUES RTE in the rangetable with the RESULT RTE.
2005 : : *
2006 : : * rte is the RangeTblEntry referenced by jtnode. Because of the limited
2007 : : * possible usage of VALUES RTEs, we do not need the remaining parameters
2008 : : * of pull_up_subqueries_recurse.
2009 : : */
2010 : : static Node *
2011 : 2297 : pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
2012 : : {
2013 : 2297 : Query *parse = root->parse;
2014 : 2297 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2015 : : List *values_list;
2016 : : List *tlist;
2017 : : AttrNumber attrno;
2018 : : pullup_replace_vars_context rvcontext;
2019 : : ListCell *lc;
2020 : :
2021 [ - + ]: 2297 : Assert(rte->rtekind == RTE_VALUES);
2022 [ - + ]: 2297 : Assert(list_length(rte->values_lists) == 1);
2023 : :
2024 : : /*
2025 : : * Need a modifiable copy of the VALUES list to hack on, just in case it's
2026 : : * multiply referenced.
2027 : : */
3205 peter_e@gmx.net 2028 : 2297 : values_list = copyObject(linitial(rte->values_lists));
2029 : :
2030 : : /*
2031 : : * The VALUES RTE can't contain any Vars of level zero, let alone any that
2032 : : * are join aliases, so no need to flatten join alias Vars.
2033 : : */
3934 tgl@sss.pgh.pa.us 2034 [ - + ]: 2297 : Assert(!contain_vars_of_level((Node *) values_list, 0));
2035 : :
2036 : : /*
2037 : : * Set up required context data for pullup_replace_vars. In particular,
2038 : : * we have to make the VALUES list look like a subquery targetlist.
2039 : : */
2040 : 2297 : tlist = NIL;
2041 : 2297 : attrno = 1;
2042 [ + + + + : 4964 : foreach(lc, values_list)
+ + ]
2043 : : {
2044 : 2667 : tlist = lappend(tlist,
2045 : 2667 : makeTargetEntry((Expr *) lfirst(lc),
2046 : : attrno,
2047 : : NULL,
2048 : : false));
2049 : 2667 : attrno++;
2050 : : }
2051 : 2297 : rvcontext.root = root;
2052 : 2297 : rvcontext.targetlist = tlist;
2053 : 2297 : rvcontext.target_rte = rte;
295 rguo@postgresql.org 2054 : 2297 : rvcontext.result_relation = 0;
382 tgl@sss.pgh.pa.us 2055 : 2297 : rvcontext.relids = NULL; /* can't be any lateral references here */
2056 : 2297 : rvcontext.nullinfo = NULL;
3934 2057 : 2297 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2058 : 2297 : rvcontext.varno = varno;
279 rguo@postgresql.org 2059 : 2297 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2060 : : /* initialize cache array with indexes 0 .. length(tlist) */
3934 tgl@sss.pgh.pa.us 2061 : 2297 : rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
2062 : : sizeof(Node *));
2063 : :
2064 : : /*
2065 : : * Replace all of the top query's references to the RTE's outputs with
2066 : : * copies of the adjusted VALUES expressions, being careful not to replace
2067 : : * any of the jointree structure. We can assume there's no outer joins or
2068 : : * appendrels in the dummy Query that surrounds a VALUES RTE.
2069 : : */
1052 2070 : 2297 : perform_pullup_replace_vars(root, &rvcontext, NULL);
2071 : :
2072 : : /*
2073 : : * There should be no appendrels to fix, nor any outer joins and hence no
2074 : : * PlaceHolderVars.
2075 : : */
3934 2076 [ - + ]: 2297 : Assert(root->append_rel_list == NIL);
2077 [ - + ]: 2297 : Assert(root->join_info_list == NIL);
2078 [ - + ]: 2297 : Assert(root->placeholder_list == NIL);
2079 : :
2080 : : /*
2081 : : * Replace the VALUES RTE with a RESULT RTE. The VALUES RTE is the only
2082 : : * rtable entry in the current query level, so this is easy.
2083 : : */
2515 2084 [ - + ]: 2297 : Assert(list_length(parse->rtable) == 1);
2085 : :
2086 : : /* Create suitable RTE */
2087 : 2297 : rte = makeNode(RangeTblEntry);
2088 : 2297 : rte->rtekind = RTE_RESULT;
2089 : 2297 : rte->eref = makeAlias("*RESULT*", NIL);
2090 : :
2091 : : /* Replace rangetable */
2092 : 2297 : parse->rtable = list_make1(rte);
2093 : :
2094 : : /* We could manufacture a new RangeTblRef, but the one we have is fine */
2095 [ - + ]: 2297 : Assert(varno == 1);
2096 : :
2097 : 2297 : return jtnode;
2098 : : }
2099 : :
2100 : : /*
2101 : : * is_simple_values
2102 : : * Check a VALUES RTE in the range table to see if it's simple enough
2103 : : * to pull up into the parent query.
2104 : : *
2105 : : * rte is the RTE_VALUES RangeTblEntry to check.
2106 : : */
2107 : : static bool
2108 : 6539 : is_simple_values(PlannerInfo *root, RangeTblEntry *rte)
2109 : : {
3934 2110 [ - + ]: 6539 : Assert(rte->rtekind == RTE_VALUES);
2111 : :
2112 : : /*
2113 : : * There must be exactly one VALUES list, else it's not semantically
2114 : : * correct to replace the VALUES RTE with a RESULT RTE, nor would we have
2115 : : * a unique set of expressions to substitute into the parent query.
2116 : : */
2117 [ + + ]: 6539 : if (list_length(rte->values_lists) != 1)
2118 : 4242 : return false;
2119 : :
2120 : : /*
2121 : : * Because VALUES can't appear under an outer join (or at least, we won't
2122 : : * try to pull it up if it does), we need not worry about LATERAL, nor
2123 : : * about validity of PHVs for the VALUES' outputs.
2124 : : */
2125 : :
2126 : : /*
2127 : : * Don't pull up a VALUES that contains any set-returning or volatile
2128 : : * functions. The considerations here are basically identical to the
2129 : : * restrictions on a pull-able subquery's targetlist.
2130 : : */
2131 [ + - - + ]: 4594 : if (expression_returns_set((Node *) rte->values_lists) ||
2132 : 2297 : contain_volatile_functions((Node *) rte->values_lists))
3934 tgl@sss.pgh.pa.us 2133 :UBC 0 : return false;
2134 : :
2135 : : /*
2136 : : * Do not pull up a VALUES that's not the only RTE in its parent query.
2137 : : * This is actually the only case that the parser will generate at the
2138 : : * moment, and assuming this is true greatly simplifies
2139 : : * pull_up_simple_values().
2140 : : */
3934 tgl@sss.pgh.pa.us 2141 [ + - ]:CBC 2297 : if (list_length(root->parse->rtable) != 1 ||
2142 [ - + ]: 2297 : rte != (RangeTblEntry *) linitial(root->parse->rtable))
8367 tgl@sss.pgh.pa.us 2143 :UBC 0 : return false;
2144 : :
8367 tgl@sss.pgh.pa.us 2145 :CBC 2297 : return true;
2146 : : }
2147 : :
2148 : : /*
2149 : : * pull_up_constant_function
2150 : : * Pull up an RTE_FUNCTION expression that was simplified to a constant.
2151 : : *
2152 : : * jtnode is a RangeTblRef that has been identified as a FUNCTION RTE by
2153 : : * pull_up_subqueries. If its expression is just a Const, hoist that value
2154 : : * up into the parent query, and replace the RTE_FUNCTION with RTE_RESULT.
2155 : : *
2156 : : * In principle we could pull up any immutable expression, but we don't.
2157 : : * That might result in multiple evaluations of the expression, which could
2158 : : * be costly if it's not just a Const. Also, the main value of this is
2159 : : * to let the constant participate in further const-folding, and of course
2160 : : * that won't happen for a non-Const.
2161 : : *
2162 : : * The pulled-up value might need to be wrapped in a PlaceHolderVar if the
2163 : : * RTE is below an outer join or is part of an appendrel; the extra
2164 : : * parameters show whether that's needed.
2165 : : */
2166 : : static Node *
2330 2167 : 25301 : pull_up_constant_function(PlannerInfo *root, Node *jtnode,
2168 : : RangeTblEntry *rte,
2169 : : AppendRelInfo *containing_appendrel)
2170 : : {
2171 : 25301 : Query *parse = root->parse;
2172 : : RangeTblFunction *rtf;
2173 : : TypeFuncClass functypclass;
2174 : : Oid funcrettype;
2175 : : TupleDesc tupdesc;
2176 : : pullup_replace_vars_context rvcontext;
2177 : :
2178 : : /* Fail if the RTE has ORDINALITY - we don't implement that here. */
2179 [ + + ]: 25301 : if (rte->funcordinality)
2180 : 479 : return jtnode;
2181 : :
2182 : : /* Fail if RTE isn't a single, simple Const expr */
2183 [ + + ]: 24822 : if (list_length(rte->functions) != 1)
2184 : 36 : return jtnode;
2185 : 24786 : rtf = linitial_node(RangeTblFunction, rte->functions);
2186 [ + + ]: 24786 : if (!IsA(rtf->funcexpr, Const))
2187 : 24600 : return jtnode;
2188 : :
2189 : : /*
2190 : : * If the function's result is not a scalar, we punt. In principle we
2191 : : * could break the composite constant value apart into per-column
2192 : : * constants, but for now it seems not worth the work.
2193 : : */
2276 2194 [ + + ]: 186 : if (rtf->funccolcount != 1)
2195 : 15 : return jtnode; /* definitely composite */
2196 : :
2197 : : /* If it has a coldeflist, it certainly returns RECORD */
611 2198 [ - + ]: 171 : if (rtf->funccolnames != NIL)
611 tgl@sss.pgh.pa.us 2199 :UBC 0 : return jtnode; /* must be a one-column RECORD type */
2200 : :
2276 tgl@sss.pgh.pa.us 2201 :CBC 171 : functypclass = get_expr_result_type(rtf->funcexpr,
2202 : : &funcrettype,
2203 : : &tupdesc);
2204 [ + + ]: 171 : if (functypclass != TYPEFUNC_SCALAR)
2205 : 6 : return jtnode; /* must be a one-column composite type */
2206 : :
2207 : : /* Create context for applying pullup_replace_vars */
2330 2208 : 165 : rvcontext.root = root;
2209 : 165 : rvcontext.targetlist = list_make1(makeTargetEntry((Expr *) rtf->funcexpr,
2210 : : 1, /* resno */
2211 : : NULL, /* resname */
2212 : : false)); /* resjunk */
2213 : 165 : rvcontext.target_rte = rte;
295 rguo@postgresql.org 2214 : 165 : rvcontext.result_relation = 0;
2215 : :
2216 : : /*
2217 : : * Since this function was reduced to a Const, it doesn't contain any
2218 : : * lateral references, even if it's marked as LATERAL. This means we
2219 : : * don't need to fill relids or nullinfo.
2220 : : */
2330 tgl@sss.pgh.pa.us 2221 : 165 : rvcontext.relids = NULL;
382 2222 : 165 : rvcontext.nullinfo = NULL;
2223 : :
2330 2224 : 165 : rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
2225 : 165 : rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
2226 : : /* this flag will be set below, if needed */
279 rguo@postgresql.org 2227 : 165 : rvcontext.wrap_option = REPLACE_WRAP_NONE;
2228 : : /* initialize cache array with indexes 0 .. length(tlist) */
2330 tgl@sss.pgh.pa.us 2229 : 165 : rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
2230 : : sizeof(Node *));
2231 : :
2232 : : /*
2233 : : * If the parent query uses grouping sets, we need a PlaceHolderVar for
2234 : : * each expression of the subquery's targetlist items. (See comments in
2235 : : * pull_up_simple_subquery().)
2236 : : */
2237 [ - + ]: 165 : if (parse->groupingSets)
279 rguo@postgresql.org 2238 :UBC 0 : rvcontext.wrap_option = REPLACE_WRAP_ALL;
2239 : :
2240 : : /*
2241 : : * Replace all of the top query's references to the RTE's output with
2242 : : * copies of the funcexpr, being careful not to replace any of the
2243 : : * jointree structure.
2244 : : */
2330 tgl@sss.pgh.pa.us 2245 :CBC 165 : perform_pullup_replace_vars(root, &rvcontext,
2246 : : containing_appendrel);
2247 : :
2248 : : /*
2249 : : * We don't need to bother with changing PlaceHolderVars in the parent
2250 : : * query. Their references to the RT index are still good for now, and
2251 : : * will get removed later if we're able to drop the RTE_RESULT.
2252 : : */
2253 : :
2254 : : /*
2255 : : * Convert the RTE to be RTE_RESULT type, signifying that we don't need to
2256 : : * scan it anymore, and zero out RTE_FUNCTION-specific fields. Also make
2257 : : * sure the RTE is not marked LATERAL, since elsewhere we don't expect
2258 : : * RTE_RESULTs to be LATERAL.
2259 : : */
2260 : 165 : rte->rtekind = RTE_RESULT;
2261 : 165 : rte->functions = NIL;
1622 2262 : 165 : rte->lateral = false;
2263 : :
2264 : : /*
2265 : : * We can reuse the RangeTblRef node.
2266 : : */
2330 2267 : 165 : return jtnode;
2268 : : }
2269 : :
2270 : : /*
2271 : : * is_simple_union_all
2272 : : * Check a subquery to see if it's a simple UNION ALL.
2273 : : *
2274 : : * We require all the setops to be UNION ALL (no mixing) and there can't be
2275 : : * any datatype coercions involved, ie, all the leaf queries must emit the
2276 : : * same datatypes.
2277 : : */
2278 : : static bool
7257 2279 : 14180 : is_simple_union_all(Query *subquery)
2280 : : {
2281 : : SetOperationStmt *topop;
2282 : :
2283 : : /* Let's just make sure it's a valid subselect ... */
2284 [ + - ]: 14180 : if (!IsA(subquery, Query) ||
3259 2285 [ - + ]: 14180 : subquery->commandType != CMD_SELECT)
7257 tgl@sss.pgh.pa.us 2286 [ # # ]:UBC 0 : elog(ERROR, "subquery is bogus");
2287 : :
2288 : : /* Is it a set-operation query at all? */
3221 peter_e@gmx.net 2289 :CBC 14180 : topop = castNode(SetOperationStmt, subquery->setOperations);
7257 tgl@sss.pgh.pa.us 2290 [ + + ]: 14180 : if (!topop)
2291 : 11272 : return false;
2292 : :
2293 : : /* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
2294 [ + + ]: 2908 : if (subquery->sortClause ||
2295 [ + - ]: 2876 : subquery->limitOffset ||
2296 [ + - ]: 2876 : subquery->limitCount ||
6283 2297 [ + - ]: 2876 : subquery->rowMarks ||
2298 [ + + ]: 2876 : subquery->cteList)
7257 2299 : 130 : return false;
2300 : :
2301 : : /* Recursively check the tree of set operations */
2302 : 2778 : return is_simple_union_all_recurse((Node *) topop, subquery,
2303 : : topop->colTypes);
2304 : : }
2305 : :
2306 : : static bool
2307 : 17607 : is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
2308 : : {
2309 : : /* Since this function recurses, it could be driven to stack overflow. */
1091 2310 : 17607 : check_stack_depth();
2311 : :
7257 2312 [ + + ]: 17607 : if (IsA(setOp, RangeTblRef))
2313 : : {
2314 : 8976 : RangeTblRef *rtr = (RangeTblRef *) setOp;
2315 : 8976 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
2316 : 8976 : Query *subquery = rte->subquery;
2317 : :
2318 [ - + ]: 8976 : Assert(subquery != NULL);
2319 : :
2320 : : /* Leaf nodes are OK if they match the toplevel column types */
2321 : : /* We don't have to compare typmods or collations here */
2322 : 8976 : return tlist_same_datatypes(subquery->targetList, colTypes, true);
2323 : : }
2324 [ + - ]: 8631 : else if (IsA(setOp, SetOperationStmt))
2325 : : {
2326 : 8631 : SetOperationStmt *op = (SetOperationStmt *) setOp;
2327 : :
2328 : : /* Must be UNION ALL */
2329 [ + + + + ]: 8631 : if (op->op != SETOP_UNION || !op->all)
2330 : 2552 : return false;
2331 : :
2332 : : /* Recurse to check inputs */
2333 [ + + + + ]: 11778 : return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
2334 : 5699 : is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
2335 : : }
2336 : : else
2337 : : {
7257 tgl@sss.pgh.pa.us 2338 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
2339 : : (int) nodeTag(setOp));
2340 : : return false; /* keep compiler quiet */
2341 : : }
2342 : : }
2343 : :
2344 : : /*
2345 : : * is_safe_append_member
2346 : : * Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
2347 : : * safe to pull up.
2348 : : */
2349 : : static bool
7257 tgl@sss.pgh.pa.us 2350 :CBC 9660 : is_safe_append_member(Query *subquery)
2351 : : {
2352 : : FromExpr *jtnode;
2353 : :
2354 : : /*
2355 : : * It's only safe to pull up the child if its jointree contains exactly
2356 : : * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
2357 : : * could be buried in several levels of FromExpr, however. Also, if the
2358 : : * child's jointree is completely empty, we can pull up because
2359 : : * pull_up_simple_subquery will insert a single RTE_RESULT RTE instead.
2360 : : *
2361 : : * Also, the child can't have any WHERE quals because there's no place to
2362 : : * put them in an appendrel. (This is a bit annoying...) If we didn't
2363 : : * need to check this, we'd just test whether get_relids_in_jointree()
2364 : : * yields a singleton set, to be more consistent with the coding of
2365 : : * fix_append_rel_relids().
2366 : : */
2367 : 9660 : jtnode = subquery->jointree;
2515 2368 [ - + ]: 9660 : Assert(IsA(jtnode, FromExpr));
2369 : : /* Check the completely-empty case */
2370 [ + + + + ]: 9660 : if (jtnode->fromlist == NIL && jtnode->quals == NULL)
2371 : 292 : return true;
2372 : : /* Check the more general case */
7257 2373 [ + + ]: 16469 : while (IsA(jtnode, FromExpr))
2374 : : {
2375 [ + + ]: 9374 : if (jtnode->quals != NULL)
2376 : 2273 : return false;
2377 [ - + ]: 7101 : if (list_length(jtnode->fromlist) != 1)
7257 tgl@sss.pgh.pa.us 2378 :UBC 0 : return false;
7257 tgl@sss.pgh.pa.us 2379 :CBC 7101 : jtnode = linitial(jtnode->fromlist);
2380 : : }
2381 [ + + ]: 7095 : if (!IsA(jtnode, RangeTblRef))
2382 : 893 : return false;
2383 : :
2384 : 6202 : return true;
2385 : : }
2386 : :
2387 : : /*
2388 : : * jointree_contains_lateral_outer_refs
2389 : : * Check for disallowed lateral references in a jointree's quals
2390 : : *
2391 : : * If restricted is false, all level-1 Vars are allowed (but we still must
2392 : : * search the jointree, since it might contain outer joins below which there
2393 : : * will be restrictions). If restricted is true, return true when any qual
2394 : : * in the jointree contains level-1 Vars coming from outside the rels listed
2395 : : * in safe_upper_varnos.
2396 : : */
2397 : : static bool
1791 2398 : 2604 : jointree_contains_lateral_outer_refs(PlannerInfo *root, Node *jtnode,
2399 : : bool restricted,
2400 : : Relids safe_upper_varnos)
2401 : : {
4503 2402 [ - + ]: 2604 : if (jtnode == NULL)
4503 tgl@sss.pgh.pa.us 2403 :UBC 0 : return false;
4503 tgl@sss.pgh.pa.us 2404 [ + + ]:CBC 2604 : if (IsA(jtnode, RangeTblRef))
2405 : 1209 : return false;
2406 [ + + ]: 1395 : else if (IsA(jtnode, FromExpr))
2407 : : {
2408 : 1238 : FromExpr *f = (FromExpr *) jtnode;
2409 : : ListCell *l;
2410 : :
2411 : : /* First, recurse to check child joins */
2412 [ + + + + : 2302 : foreach(l, f->fromlist)
+ + ]
2413 : : {
1791 2414 [ + + ]: 1076 : if (jointree_contains_lateral_outer_refs(root,
2415 : 1076 : lfirst(l),
2416 : : restricted,
2417 : : safe_upper_varnos))
4503 2418 : 12 : return true;
2419 : : }
2420 : :
2421 : : /* Then check the top-level quals */
2422 [ + + ]: 1226 : if (restricted &&
1791 2423 [ - + ]: 714 : !bms_is_subset(pull_varnos_of_level(root, f->quals, 1),
2424 : : safe_upper_varnos))
4503 tgl@sss.pgh.pa.us 2425 :UBC 0 : return true;
2426 : : }
4503 tgl@sss.pgh.pa.us 2427 [ + - ]:CBC 157 : else if (IsA(jtnode, JoinExpr))
2428 : : {
2429 : 157 : JoinExpr *j = (JoinExpr *) jtnode;
2430 : :
2431 : : /*
2432 : : * If this is an outer join, we mustn't allow any upper lateral
2433 : : * references in or below it.
2434 : : */
2435 [ + + ]: 157 : if (j->jointype != JOIN_INNER)
2436 : : {
2437 : 79 : restricted = true;
2438 : 79 : safe_upper_varnos = NULL;
2439 : : }
2440 : :
2441 : : /* Check the child joins */
1791 2442 [ - + ]: 157 : if (jointree_contains_lateral_outer_refs(root,
2443 : : j->larg,
2444 : : restricted,
2445 : : safe_upper_varnos))
4503 tgl@sss.pgh.pa.us 2446 :UBC 0 : return true;
1791 tgl@sss.pgh.pa.us 2447 [ - + ]:CBC 157 : if (jointree_contains_lateral_outer_refs(root,
2448 : : j->rarg,
2449 : : restricted,
2450 : : safe_upper_varnos))
4503 tgl@sss.pgh.pa.us 2451 :UBC 0 : return true;
2452 : :
2453 : : /* Check the JOIN's qual clauses */
4503 tgl@sss.pgh.pa.us 2454 [ + + ]:CBC 157 : if (restricted &&
1791 2455 [ + + ]: 145 : !bms_is_subset(pull_varnos_of_level(root, j->quals, 1),
2456 : : safe_upper_varnos))
4503 2457 : 12 : return true;
2458 : : }
2459 : : else
4503 tgl@sss.pgh.pa.us 2460 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
2461 : : (int) nodeTag(jtnode));
4503 tgl@sss.pgh.pa.us 2462 :CBC 1371 : return false;
2463 : : }
2464 : :
2465 : : /*
2466 : : * Perform pullup_replace_vars everyplace it's needed in the query tree.
2467 : : *
2468 : : * Caller has already filled *rvcontext with data describing what to
2469 : : * substitute for Vars referencing the target subquery. In addition
2470 : : * we need the identity of the containing appendrel if any.
2471 : : */
2472 : : static void
2330 2473 : 21286 : perform_pullup_replace_vars(PlannerInfo *root,
2474 : : pullup_replace_vars_context *rvcontext,
2475 : : AppendRelInfo *containing_appendrel)
2476 : : {
2477 : 21286 : Query *parse = root->parse;
2478 : : ListCell *lc;
2479 : :
2480 : : /*
2481 : : * If we are considering an appendrel child subquery (that is, a UNION ALL
2482 : : * member query that we're pulling up), then the only part of the upper
2483 : : * query that could reference the child yet is the translated_vars list of
2484 : : * the associated AppendRelInfo. Furthermore, we do not want to force use
2485 : : * of PHVs in the AppendRelInfo --- there isn't any outer join between.
2486 : : */
1091 2487 [ + + ]: 21286 : if (containing_appendrel)
2488 : : {
279 rguo@postgresql.org 2489 : 3190 : ReplaceWrapOption save_wrap_option = rvcontext->wrap_option;
2490 : :
2491 : 3190 : rvcontext->wrap_option = REPLACE_WRAP_NONE;
1091 tgl@sss.pgh.pa.us 2492 : 3190 : containing_appendrel->translated_vars = (List *)
2493 : 3190 : pullup_replace_vars((Node *) containing_appendrel->translated_vars,
2494 : : rvcontext);
279 rguo@postgresql.org 2495 : 3190 : rvcontext->wrap_option = save_wrap_option;
1091 tgl@sss.pgh.pa.us 2496 : 3190 : return;
2497 : : }
2498 : :
2499 : : /*
2500 : : * Replace all of the top query's references to the subquery's outputs
2501 : : * with copies of the adjusted subtlist items, being careful not to
2502 : : * replace any of the jointree structure. (This'd be a lot cleaner if we
2503 : : * could use query_tree_mutator.) We have to use PHVs in the targetList,
2504 : : * returningList, and havingQual, since those are certainly above any
2505 : : * outer join. replace_vars_in_jointree tracks its location in the
2506 : : * jointree and uses PHVs or not appropriately.
2507 : : */
2330 2508 : 18096 : parse->targetList = (List *)
2509 : 18096 : pullup_replace_vars((Node *) parse->targetList, rvcontext);
2510 : 18096 : parse->returningList = (List *)
2511 : 18096 : pullup_replace_vars((Node *) parse->returningList, rvcontext);
2512 : :
2513 [ + + ]: 18096 : if (parse->onConflict)
2514 : : {
2515 : 22 : parse->onConflict->onConflictSet = (List *)
2516 : 11 : pullup_replace_vars((Node *) parse->onConflict->onConflictSet,
2517 : : rvcontext);
2518 : 11 : parse->onConflict->onConflictWhere =
2519 : 11 : pullup_replace_vars(parse->onConflict->onConflictWhere,
2520 : : rvcontext);
2521 : :
2522 : : /*
2523 : : * We assume ON CONFLICT's arbiterElems, arbiterWhere, exclRelTlist
2524 : : * can't contain any references to a subquery.
2525 : : */
2526 : : }
1360 alvherre@alvh.no-ip. 2527 [ + + ]: 18096 : if (parse->mergeActionList)
2528 : : {
2529 [ + - + + : 1519 : foreach(lc, parse->mergeActionList)
+ + ]
2530 : : {
2531 : 907 : MergeAction *action = lfirst(lc);
2532 : :
2533 : 907 : action->qual = pullup_replace_vars(action->qual, rvcontext);
2534 : 907 : action->targetList = (List *)
2535 : 907 : pullup_replace_vars((Node *) action->targetList, rvcontext);
2536 : : }
2537 : : }
627 dean.a.rasheed@gmail 2538 : 18096 : parse->mergeJoinCondition = pullup_replace_vars(parse->mergeJoinCondition,
2539 : : rvcontext);
1052 tgl@sss.pgh.pa.us 2540 : 18096 : replace_vars_in_jointree((Node *) parse->jointree, rvcontext);
2330 2541 [ - + ]: 18093 : Assert(parse->setOperations == NULL);
2542 : 18093 : parse->havingQual = pullup_replace_vars(parse->havingQual, rvcontext);
2543 : :
2544 : : /*
2545 : : * Replace references in the translated_vars lists of appendrels.
2546 : : */
2547 [ + + + + : 18111 : foreach(lc, root->append_rel_list)
+ + ]
2548 : : {
2549 : 18 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
2550 : :
2551 : 18 : appinfo->translated_vars = (List *)
2552 : 18 : pullup_replace_vars((Node *) appinfo->translated_vars, rvcontext);
2553 : : }
2554 : :
2555 : : /*
2556 : : * Replace references in the joinaliasvars lists of join RTEs and the
2557 : : * groupexprs list of group RTE.
2558 : : */
2559 [ + - + + : 50578 : foreach(lc, parse->rtable)
+ + ]
2560 : : {
2561 : 32485 : RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(lc);
2562 : :
2563 [ + + ]: 32485 : if (otherrte->rtekind == RTE_JOIN)
2564 : 3452 : otherrte->joinaliasvars = (List *)
2565 : 3452 : pullup_replace_vars((Node *) otherrte->joinaliasvars,
2566 : : rvcontext);
463 rguo@postgresql.org 2567 [ + + ]: 29033 : else if (otherrte->rtekind == RTE_GROUP)
2568 : 369 : otherrte->groupexprs = (List *)
2569 : 369 : pullup_replace_vars((Node *) otherrte->groupexprs,
2570 : : rvcontext);
2571 : : }
2572 : : }
2573 : :
2574 : : /*
2575 : : * Helper routine for perform_pullup_replace_vars: do pullup_replace_vars on
2576 : : * every expression in the jointree, without changing the jointree structure
2577 : : * itself. Ugly, but there's no other way...
2578 : : */
2579 : : static void
5950 tgl@sss.pgh.pa.us 2580 : 47299 : replace_vars_in_jointree(Node *jtnode,
2581 : : pullup_replace_vars_context *context)
2582 : : {
8367 2583 [ - + ]: 47299 : if (jtnode == NULL)
8367 tgl@sss.pgh.pa.us 2584 :UBC 0 : return;
8367 tgl@sss.pgh.pa.us 2585 [ + + ]:CBC 47299 : if (IsA(jtnode, RangeTblRef))
2586 : : {
2587 : : /*
2588 : : * If the RangeTblRef refers to a LATERAL subquery (that isn't the
2589 : : * same subquery we're pulling up), it might contain references to the
2590 : : * target subquery, which we must replace. We drive this from the
2591 : : * jointree scan, rather than a scan of the rtable, so that we can
2592 : : * avoid processing no-longer-referenced RTEs.
2593 : : */
4869 2594 : 23744 : int varno = ((RangeTblRef *) jtnode)->rtindex;
2595 : :
2596 [ + + ]: 23744 : if (varno != context->varno) /* ignore target subquery itself */
2597 : : {
2598 : 5648 : RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
2599 : :
2600 [ - + ]: 5648 : Assert(rte != context->target_rte);
2601 [ + + ]: 5648 : if (rte->lateral)
2602 : : {
2603 [ - + + + : 461 : switch (rte->rtekind)
- - - ]
2604 : : {
3798 tgl@sss.pgh.pa.us 2605 :UBC 0 : case RTE_RELATION:
2606 : : /* shouldn't be marked LATERAL unless tablesample */
2607 [ # # ]: 0 : Assert(rte->tablesample);
2608 : 0 : rte->tablesample = (TableSampleClause *)
2609 : 0 : pullup_replace_vars((Node *) rte->tablesample,
2610 : : context);
2611 : 0 : break;
4869 tgl@sss.pgh.pa.us 2612 :CBC 225 : case RTE_SUBQUERY:
2613 : 225 : rte->subquery =
2614 : 225 : pullup_replace_vars_subquery(rte->subquery,
2615 : : context);
2616 : 225 : break;
2617 : 182 : case RTE_FUNCTION:
4409 2618 : 182 : rte->functions = (List *)
2619 : 182 : pullup_replace_vars((Node *) rte->functions,
2620 : : context);
4869 2621 : 182 : break;
3206 alvherre@alvh.no-ip. 2622 : 54 : case RTE_TABLEFUNC:
2623 : 54 : rte->tablefunc = (TableFunc *)
2624 : 54 : pullup_replace_vars((Node *) rte->tablefunc,
2625 : : context);
2626 : 54 : break;
4869 tgl@sss.pgh.pa.us 2627 :UBC 0 : case RTE_VALUES:
2628 : 0 : rte->values_lists = (List *)
2629 : 0 : pullup_replace_vars((Node *) rte->values_lists,
2630 : : context);
2631 : 0 : break;
2632 : 0 : case RTE_JOIN:
2633 : : case RTE_CTE:
2634 : : case RTE_NAMEDTUPLESTORE:
2635 : : case RTE_RESULT:
2636 : : case RTE_GROUP:
2637 : : /* these shouldn't be marked LATERAL */
2638 : 0 : Assert(false);
2639 : : break;
2640 : : }
2641 : : }
2642 : : }
2643 : : }
8367 tgl@sss.pgh.pa.us 2644 [ + + ]:CBC 23555 : else if (IsA(jtnode, FromExpr))
2645 : : {
2646 : 19474 : FromExpr *f = (FromExpr *) jtnode;
2647 : : ListCell *l;
2648 : :
2649 [ + - + + : 40515 : foreach(l, f->fromlist)
+ + ]
1052 2650 : 21041 : replace_vars_in_jointree(lfirst(l), context);
5950 2651 : 19474 : f->quals = pullup_replace_vars(f->quals, context);
2652 : : }
8367 2653 [ + - ]: 4081 : else if (IsA(jtnode, JoinExpr))
2654 : : {
2655 : 4081 : JoinExpr *j = (JoinExpr *) jtnode;
279 rguo@postgresql.org 2656 : 4081 : ReplaceWrapOption save_wrap_option = context->wrap_option;
2657 : :
1052 tgl@sss.pgh.pa.us 2658 : 4081 : replace_vars_in_jointree(j->larg, context);
2659 : 4081 : replace_vars_in_jointree(j->rarg, context);
2660 : :
2661 : : /*
2662 : : * Use PHVs within the join quals of a full join for variable-free
2663 : : * expressions. Otherwise, we cannot identify which side of the join
2664 : : * a pulled-up variable-free expression came from, which can lead to
2665 : : * failure to make a plan at all because none of the quals appear to
2666 : : * be mergeable or hashable conditions.
2667 : : */
2621 2668 [ + + ]: 4081 : if (j->jointype == JOIN_FULL)
279 rguo@postgresql.org 2669 : 314 : context->wrap_option = REPLACE_WRAP_VARFREE;
2670 : :
5950 tgl@sss.pgh.pa.us 2671 : 4081 : j->quals = pullup_replace_vars(j->quals, context);
2672 : :
279 rguo@postgresql.org 2673 : 4081 : context->wrap_option = save_wrap_option;
2674 : : }
2675 : : else
8181 tgl@sss.pgh.pa.us 2676 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
2677 : : (int) nodeTag(jtnode));
2678 : : }
2679 : :
2680 : : /*
2681 : : * Apply pullup variable replacement throughout an expression tree
2682 : : *
2683 : : * Returns a modified copy of the tree, so this can't be used where we
2684 : : * need to do in-place replacement.
2685 : : */
2686 : : static Node *
5950 tgl@sss.pgh.pa.us 2687 :CBC 105588 : pullup_replace_vars(Node *expr, pullup_replace_vars_context *context)
2688 : : {
2689 : 105588 : return replace_rte_variables(expr,
2690 : : context->varno, 0,
2691 : : pullup_replace_vars_callback,
2692 : : context,
2693 : : context->outer_hasSubLinks);
2694 : : }
2695 : :
2696 : : static Node *
2697 : 58571 : pullup_replace_vars_callback(Var *var,
2698 : : replace_rte_variables_context *context)
2699 : : {
2700 : 58571 : pullup_replace_vars_context *rcon = (pullup_replace_vars_context *) context->callback_arg;
2701 : 58571 : int varattno = var->varattno;
2702 : : bool need_phv;
2703 : : Node *newnode;
2704 : :
2705 : : /* System columns are not replaced. */
295 rguo@postgresql.org 2706 [ + + ]: 58571 : if (varattno < InvalidAttrNumber)
2707 : 21 : return (Node *) copyObject(var);
2708 : :
2709 : : /*
2710 : : * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
2711 : : * varnullingrels (unless we find below that the replacement expression is
2712 : : * a Var or PlaceHolderVar that we can just add the nullingrels to). We
2713 : : * also need one if the caller has instructed us that certain expression
2714 : : * replacements need to be wrapped for identification purposes.
2715 : : */
279 2716 [ + + ]: 111154 : need_phv = (var->varnullingrels != NULL) ||
2717 [ + + ]: 52604 : (rcon->wrap_option != REPLACE_WRAP_NONE);
2718 : :
2719 : : /*
2720 : : * If PlaceHolderVars are needed, we cache the modified expressions in
2721 : : * rcon->rv_cache[]. This is not in hopes of any material speed gain
2722 : : * within this function, but to avoid generating identical PHVs with
2723 : : * different IDs. That would result in duplicate evaluations at runtime,
2724 : : * and possibly prevent optimizations that rely on recognizing different
2725 : : * references to the same subquery output as being equal(). So it's worth
2726 : : * a bit of extra effort to avoid it.
2727 : : *
2728 : : * The cached items have phlevelsup = 0 and phnullingrels = NULL; we'll
2729 : : * copy them and adjust those values for this reference site below.
2730 : : */
1052 tgl@sss.pgh.pa.us 2731 [ + + + - ]: 58550 : if (need_phv &&
5950 2732 [ + - ]: 6929 : varattno >= InvalidAttrNumber &&
2733 : 6929 : varattno <= list_length(rcon->targetlist) &&
2734 [ + + ]: 6929 : rcon->rv_cache[varattno] != NULL)
2735 : : {
2736 : : /* Just copy the entry and fall through to adjust phlevelsup etc */
2737 : 1418 : newnode = copyObject(rcon->rv_cache[varattno]);
2738 : : }
2739 : : else
2740 : : {
2741 : : /*
2742 : : * Generate the replacement expression. This takes care of expanding
2743 : : * wholerow references and dealing with non-default varreturningtype.
2744 : : */
295 rguo@postgresql.org 2745 : 57132 : newnode = ReplaceVarFromTargetList(var,
2746 : : rcon->target_rte,
2747 : : rcon->targetlist,
2748 : : rcon->result_relation,
2749 : : REPLACEVARS_REPORT_ERROR,
2750 : : 0);
2751 : :
2752 : : /* Insert PlaceHolderVar if needed */
1052 tgl@sss.pgh.pa.us 2753 [ + + ]: 57132 : if (need_phv)
2754 : : {
2755 : : bool wrap;
2756 : :
279 rguo@postgresql.org 2757 [ + + ]: 5511 : if (rcon->wrap_option == REPLACE_WRAP_ALL)
2758 : : {
2759 : : /* Caller told us to wrap all expressions in a PlaceHolderVar */
2760 : 400 : wrap = true;
2761 : : }
2762 [ + + ]: 5111 : else if (varattno == InvalidAttrNumber)
2763 : : {
2764 : : /*
2765 : : * Insert PlaceHolderVar for whole-tuple reference. Notice
2766 : : * that we are wrapping one PlaceHolderVar around the whole
2767 : : * RowExpr, rather than putting one around each element of the
2768 : : * row. This is because we need the expression to yield NULL,
2769 : : * not ROW(NULL,NULL,...) when it is forced to null by an
2770 : : * outer join.
2771 : : */
295 2772 : 36 : wrap = true;
2773 : : }
2774 [ + - + + ]: 5075 : else if (newnode && IsA(newnode, Var) &&
2775 [ + + ]: 4058 : ((Var *) newnode)->varlevelsup == 0)
2776 : : {
2777 : : /*
2778 : : * Simple Vars always escape being wrapped, unless they are
2779 : : * lateral references to something outside the subquery being
2780 : : * pulled up and the referenced rel is not under the same
2781 : : * lowest nulling outer join.
2782 : : */
373 2783 : 4050 : wrap = false;
4505 tgl@sss.pgh.pa.us 2784 [ + + ]: 4050 : if (rcon->target_rte->lateral &&
2785 [ + + ]: 705 : !bms_is_member(((Var *) newnode)->varno, rcon->relids))
2786 : : {
373 rguo@postgresql.org 2787 : 66 : nullingrel_info *nullinfo = rcon->nullinfo;
2788 : 66 : int lvarno = ((Var *) newnode)->varno;
2789 : :
2790 [ + - - + ]: 66 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2791 [ + + ]: 66 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2792 : 66 : nullinfo->nullingrels[lvarno]))
2793 : 54 : wrap = true;
2794 : : }
2795 : : }
5244 tgl@sss.pgh.pa.us 2796 [ + - + + ]: 1025 : else if (newnode && IsA(newnode, PlaceHolderVar) &&
2797 [ + - ]: 90 : ((PlaceHolderVar *) newnode)->phlevelsup == 0)
2798 : : {
2799 : : /* The same rules apply for a PlaceHolderVar */
373 rguo@postgresql.org 2800 : 90 : wrap = false;
706 tgl@sss.pgh.pa.us 2801 [ + + ]: 90 : if (rcon->target_rte->lateral &&
2802 [ + - ]: 24 : !bms_is_subset(((PlaceHolderVar *) newnode)->phrels,
2803 : 24 : rcon->relids))
2804 : : {
373 rguo@postgresql.org 2805 : 24 : nullingrel_info *nullinfo = rcon->nullinfo;
2806 : 24 : Relids lvarnos = ((PlaceHolderVar *) newnode)->phrels;
2807 : : int lvarno;
2808 : :
2809 : 24 : lvarno = -1;
2810 [ + + ]: 36 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2811 : : {
2812 [ + - - + ]: 24 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2813 [ + + ]: 24 : if (!bms_is_subset(nullinfo->nullingrels[rcon->varno],
2814 : 24 : nullinfo->nullingrels[lvarno]))
2815 : : {
2816 : 12 : wrap = true;
2817 : 12 : break;
2818 : : }
2819 : : }
2820 : : }
2821 : : }
2822 : : else
2823 : : {
2824 : : /*
2825 : : * If the node contains Var(s) or PlaceHolderVar(s) of the
2826 : : * subquery being pulled up, or of rels that are under the
2827 : : * same lowest nulling outer join as the subquery, and does
2828 : : * not contain any non-strict constructs, then instead of
2829 : : * adding a PHV on top we can add the required nullingrels to
2830 : : * those Vars/PHVs. (This is fundamentally a generalization
2831 : : * of the above cases for bare Vars and PHVs.)
2832 : : *
2833 : : * This test is somewhat expensive, but it avoids pessimizing
2834 : : * the plan in cases where the nullingrels get removed again
2835 : : * later by outer join reduction.
2836 : : *
2837 : : * Note that we don't force wrapping of expressions containing
2838 : : * lateral references, so long as they also contain Vars/PHVs
2839 : : * of the subquery, or of rels that are under the same lowest
2840 : : * nulling outer join as the subquery. This is okay because
2841 : : * of the restriction to strict constructs: if those Vars/PHVs
2842 : : * have been forced to NULL by an outer join then the end
2843 : : * result of the expression will be NULL too, regardless of
2844 : : * the lateral references. So it's not necessary to force the
2845 : : * expression to be evaluated below the outer join. This can
2846 : : * be a very valuable optimization, because it may allow us to
2847 : : * avoid using a nested loop to pass the lateral reference
2848 : : * down.
2849 : : *
2850 : : * This analysis could be tighter: in particular, a non-strict
2851 : : * construct hidden within a lower-level PlaceHolderVar is not
2852 : : * reason to add another PHV. But for now it doesn't seem
2853 : : * worth the code to be more exact. This is also why it's
2854 : : * preferable to handle bare PHVs in the above branch, rather
2855 : : * than this branch. We also prefer to handle bare Vars in a
2856 : : * separate branch, as it's cheaper this way and parallels the
2857 : : * handling of PHVs.
2858 : : *
2859 : : * For a LATERAL subquery, we have to check the actual var
2860 : : * membership of the node, but if it's non-lateral then any
2861 : : * level-zero var must belong to the subquery.
2862 : : */
365 2863 : 935 : bool contain_nullable_vars = false;
2864 : :
2865 [ + + ]: 935 : if (!rcon->target_rte->lateral)
2866 : : {
2867 [ + + ]: 821 : if (contain_vars_of_level(newnode, 0))
2868 : 267 : contain_nullable_vars = true;
2869 : : }
2870 : : else
2871 : : {
2872 : : Relids all_varnos;
2873 : :
2874 : 114 : all_varnos = pull_varnos(rcon->root, newnode);
2875 [ + + ]: 114 : if (bms_overlap(all_varnos, rcon->relids))
2876 : 66 : contain_nullable_vars = true;
2877 : : else
2878 : : {
2879 : 48 : nullingrel_info *nullinfo = rcon->nullinfo;
2880 : : int varno;
2881 : :
2882 : 48 : varno = -1;
2883 [ + + ]: 90 : while ((varno = bms_next_member(all_varnos, varno)) >= 0)
2884 : : {
2885 [ + - - + ]: 54 : Assert(varno > 0 && varno <= nullinfo->rtlength);
2886 [ + + ]: 54 : if (bms_is_subset(nullinfo->nullingrels[rcon->varno],
2887 : 54 : nullinfo->nullingrels[varno]))
2888 : : {
2889 : 12 : contain_nullable_vars = true;
2890 : 12 : break;
2891 : : }
2892 : : }
2893 : : }
2894 : : }
2895 : :
2896 [ + + ]: 935 : if (contain_nullable_vars &&
474 tgl@sss.pgh.pa.us 2897 [ + + ]: 345 : !contain_nonstrict_functions(newnode))
2898 : : {
2899 : : /* No wrap needed */
2900 : 144 : wrap = false;
2901 : : }
2902 : : else
2903 : : {
2904 : : /* Else wrap it in a PlaceHolderVar */
2905 : 791 : wrap = true;
2906 : : }
2907 : : }
2908 : :
5950 2909 [ + + ]: 5511 : if (wrap)
2910 : : {
2911 : : newnode = (Node *)
2912 : 1293 : make_placeholder_expr(rcon->root,
2913 : : (Expr *) newnode,
2914 : : bms_make_singleton(rcon->varno));
2915 : :
2916 : : /*
2917 : : * Cache it if possible (ie, if the attno is in range, which
2918 : : * it probably always should be).
2919 : : */
295 rguo@postgresql.org 2920 [ + - + - ]: 2586 : if (varattno >= InvalidAttrNumber &&
1052 tgl@sss.pgh.pa.us 2921 : 1293 : varattno <= list_length(rcon->targetlist))
2922 : 1293 : rcon->rv_cache[varattno] = copyObject(newnode);
2923 : : }
2924 : : }
2925 : : }
2926 : :
2927 : : /* Propagate any varnullingrels into the replacement expression */
2928 [ + + ]: 58550 : if (var->varnullingrels != NULL)
2929 : : {
2930 [ + + ]: 5946 : if (IsA(newnode, Var))
2931 : : {
2932 : 3751 : Var *newvar = (Var *) newnode;
2933 : :
474 2934 [ - + ]: 3751 : Assert(newvar->varlevelsup == 0);
1052 2935 : 3751 : newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
2936 : 3751 : var->varnullingrels);
2937 : : }
2938 [ + + ]: 2195 : else if (IsA(newnode, PlaceHolderVar))
2939 : : {
2940 : 2051 : PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
2941 : :
474 2942 [ - + ]: 2051 : Assert(newphv->phlevelsup == 0);
1052 2943 : 2051 : newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
2944 : 2051 : var->varnullingrels);
2945 : : }
2946 : : else
2947 : : {
2948 : : /*
2949 : : * There should be Vars/PHVs within the expression that we can
2950 : : * modify. Vars/PHVs of the subquery should have the full
2951 : : * var->varnullingrels added to them, but if there are lateral
2952 : : * references within the expression, those must be marked with
2953 : : * only the nullingrels that potentially apply to them. (This
2954 : : * corresponds to the fact that the expression will now be
2955 : : * evaluated at the join level of the Var that we are replacing:
2956 : : * the lateral references may have bubbled up through fewer outer
2957 : : * joins than the subquery's Vars have. Per the discussion above,
2958 : : * we'll still get the right answers.) That relid set could be
2959 : : * different for different lateral relations, so we have to do
2960 : : * this work for each one.
2961 : : *
2962 : : * (Currently, the restrictions in is_simple_subquery() mean that
2963 : : * at most we have to remove the lowest outer join's relid from
2964 : : * the nullingrels of a lateral reference. However, we might
2965 : : * relax those restrictions someday, so let's do this right.)
2966 : : */
382 2967 [ + + ]: 144 : if (rcon->target_rte->lateral)
2968 : : {
2969 : 42 : nullingrel_info *nullinfo = rcon->nullinfo;
2970 : : Relids lvarnos;
2971 : : int lvarno;
2972 : :
2973 : : /*
2974 : : * Identify lateral varnos used within newnode. We must do
2975 : : * this before injecting var->varnullingrels into the tree.
2976 : : */
2977 : 42 : lvarnos = pull_varnos(rcon->root, newnode);
2978 : 42 : lvarnos = bms_del_members(lvarnos, rcon->relids);
2979 : : /* For each one, add relevant nullingrels if any */
2980 : 42 : lvarno = -1;
2981 [ + + ]: 84 : while ((lvarno = bms_next_member(lvarnos, lvarno)) >= 0)
2982 : : {
2983 : : Relids lnullingrels;
2984 : :
2985 [ + - - + ]: 42 : Assert(lvarno > 0 && lvarno <= nullinfo->rtlength);
2986 : 42 : lnullingrels = bms_intersect(var->varnullingrels,
2987 : 42 : nullinfo->nullingrels[lvarno]);
2988 [ + + ]: 42 : if (!bms_is_empty(lnullingrels))
2989 : 24 : newnode = add_nulling_relids(newnode,
2990 : 24 : bms_make_singleton(lvarno),
2991 : : lnullingrels);
2992 : : }
2993 : : }
2994 : :
2995 : : /* Finally, deal with Vars/PHVs of the subquery itself */
474 2996 : 144 : newnode = add_nulling_relids(newnode,
384 2997 : 144 : rcon->relids,
474 2998 : 144 : var->varnullingrels);
2999 : : /* Assert we did put the varnullingrels into the expression */
3000 [ - + ]: 144 : Assert(bms_is_subset(var->varnullingrels,
3001 : : pull_varnos(rcon->root, newnode)));
3002 : : }
3003 : : }
3004 : :
3005 : : /* Must adjust varlevelsup if replaced Var is within a subquery */
3006 [ + + ]: 58550 : if (var->varlevelsup > 0)
3007 : 613 : IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
3008 : :
5950 3009 : 58550 : return newnode;
3010 : : }
3011 : :
3012 : : /*
3013 : : * Apply pullup variable replacement to a subquery
3014 : : *
3015 : : * This needs to be different from pullup_replace_vars() because
3016 : : * replace_rte_variables will think that it shouldn't increment sublevels_up
3017 : : * before entering the Query; so we need to call it with sublevels_up == 1.
3018 : : */
3019 : : static Query *
4869 3020 : 225 : pullup_replace_vars_subquery(Query *query,
3021 : : pullup_replace_vars_context *context)
3022 : : {
3023 [ - + ]: 225 : Assert(IsA(query, Query));
3024 : 225 : return (Query *) replace_rte_variables((Node *) query,
3025 : : context->varno, 1,
3026 : : pullup_replace_vars_callback,
3027 : : context,
3028 : : NULL);
3029 : : }
3030 : :
3031 : :
3032 : : /*
3033 : : * flatten_simple_union_all
3034 : : * Try to optimize top-level UNION ALL structure into an appendrel
3035 : : *
3036 : : * If a query's setOperations tree consists entirely of simple UNION ALL
3037 : : * operations, flatten it into an append relation, which we can process more
3038 : : * intelligently than the general setops case. Otherwise, do nothing.
3039 : : *
3040 : : * In most cases, this can succeed only for a top-level query, because for a
3041 : : * subquery in FROM, the parent query's invocation of pull_up_subqueries would
3042 : : * already have flattened the UNION via pull_up_simple_union_all. But there
3043 : : * are a few cases we can support here but not in that code path, for example
3044 : : * when the subquery also contains ORDER BY.
3045 : : */
3046 : : void
5518 3047 : 3525 : flatten_simple_union_all(PlannerInfo *root)
3048 : : {
3049 : 3525 : Query *parse = root->parse;
3050 : : SetOperationStmt *topop;
3051 : : Node *leftmostjtnode;
3052 : : int leftmostRTI;
3053 : : RangeTblEntry *leftmostRTE;
3054 : : int childRTI;
3055 : : RangeTblEntry *childRTE;
3056 : : RangeTblRef *rtr;
3057 : :
3058 : : /* Shouldn't be called unless query has setops */
3221 peter_e@gmx.net 3059 : 3525 : topop = castNode(SetOperationStmt, parse->setOperations);
3060 [ - + ]: 3525 : Assert(topop);
3061 : :
3062 : : /* Can't optimize away a recursive UNION */
5518 tgl@sss.pgh.pa.us 3063 [ + + ]: 3525 : if (root->hasRecursion)
3064 : 3128 : return;
3065 : :
3066 : : /*
3067 : : * Recursively check the tree of set operations. If not all UNION ALL
3068 : : * with identical column types, punt.
3069 : : */
3070 [ + + ]: 3051 : if (!is_simple_union_all_recurse((Node *) topop, parse, topop->colTypes))
3071 : 2654 : return;
3072 : :
3073 : : /*
3074 : : * Locate the leftmost leaf query in the setops tree. The upper query's
3075 : : * Vars all refer to this RTE (see transformSetOperationStmt).
3076 : : */
3077 : 397 : leftmostjtnode = topop->larg;
3078 [ + - + + ]: 605 : while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
3079 : 208 : leftmostjtnode = ((SetOperationStmt *) leftmostjtnode)->larg;
3080 [ + - - + ]: 397 : Assert(leftmostjtnode && IsA(leftmostjtnode, RangeTblRef));
3081 : 397 : leftmostRTI = ((RangeTblRef *) leftmostjtnode)->rtindex;
3082 : 397 : leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
3083 [ - + ]: 397 : Assert(leftmostRTE->rtekind == RTE_SUBQUERY);
3084 : :
3085 : : /*
3086 : : * Make a copy of the leftmost RTE and add it to the rtable. This copy
3087 : : * will represent the leftmost leaf query in its capacity as a member of
3088 : : * the appendrel. The original will represent the appendrel as a whole.
3089 : : * (We must do things this way because the upper query's Vars have to be
3090 : : * seen as referring to the whole appendrel.)
3091 : : */
3092 : 397 : childRTE = copyObject(leftmostRTE);
3093 : 397 : parse->rtable = lappend(parse->rtable, childRTE);
3094 : 397 : childRTI = list_length(parse->rtable);
3095 : :
3096 : : /* Modify the setops tree to reference the child copy */
3097 : 397 : ((RangeTblRef *) leftmostjtnode)->rtindex = childRTI;
3098 : :
3099 : : /* Modify the formerly-leftmost RTE to mark it as an appendrel parent */
3100 : 397 : leftmostRTE->inh = true;
3101 : :
3102 : : /*
3103 : : * Form a RangeTblRef for the appendrel, and insert it into FROM. The top
3104 : : * Query of a setops tree should have had an empty FromClause initially.
3105 : : */
3106 : 397 : rtr = makeNode(RangeTblRef);
3107 : 397 : rtr->rtindex = leftmostRTI;
3108 [ - + ]: 397 : Assert(parse->jointree->fromlist == NIL);
3109 : 397 : parse->jointree->fromlist = list_make1(rtr);
3110 : :
3111 : : /*
3112 : : * Now pretend the query has no setops. We must do this before trying to
3113 : : * do subquery pullup, because of Assert in pull_up_simple_subquery.
3114 : : */
3115 : 397 : parse->setOperations = NULL;
3116 : :
3117 : : /*
3118 : : * Build AppendRelInfo information, and apply pull_up_subqueries to the
3119 : : * leaf queries of the UNION ALL. (We must do that now because they
3120 : : * weren't previously referenced by the jointree, and so were missed by
3121 : : * the main invocation of pull_up_subqueries.)
3122 : : */
3123 : 397 : pull_up_union_leaf_queries((Node *) topop, root, leftmostRTI, parse, 0);
3124 : : }
3125 : :
3126 : :
3127 : : /*
3128 : : * reduce_outer_joins
3129 : : * Attempt to reduce outer joins to plain inner joins.
3130 : : *
3131 : : * The idea here is that given a query like
3132 : : * SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
3133 : : * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
3134 : : * is strict. The strict operator will always return NULL, causing the outer
3135 : : * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
3136 : : * columns. Therefore, there's no need for the join to produce null-extended
3137 : : * rows in the first place --- which makes it a plain join not an outer join.
3138 : : * (This scenario may not be very likely in a query written out by hand, but
3139 : : * it's reasonably likely when pushing quals down into complex views.)
3140 : : *
3141 : : * More generally, an outer join can be reduced in strength if there is a
3142 : : * strict qual above it in the qual tree that constrains a Var from the
3143 : : * nullable side of the join to be non-null. (For FULL joins this applies
3144 : : * to each side separately.)
3145 : : *
3146 : : * Another transformation we apply here is to recognize cases like
3147 : : * SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.y IS NULL;
3148 : : * If the join clause is strict for b.y, then only null-extended rows could
3149 : : * pass the upper WHERE, and we can conclude that what the query is really
3150 : : * specifying is an anti-semijoin. We change the join type from JOIN_LEFT
3151 : : * to JOIN_ANTI. The IS NULL clause then becomes redundant, and must be
3152 : : * removed to prevent bogus selectivity calculations, but we leave it to
3153 : : * distribute_qual_to_rels to get rid of such clauses.
3154 : : *
3155 : : * Also, we get rid of JOIN_RIGHT cases by flipping them around to become
3156 : : * JOIN_LEFT. This saves some code here and in some later planner routines;
3157 : : * the main benefit is to reduce the number of jointypes that can appear in
3158 : : * SpecialJoinInfo nodes. Note that we can still generate Paths and Plans
3159 : : * that use JOIN_RIGHT (or JOIN_RIGHT_ANTI) by switching the inputs again.
3160 : : *
3161 : : * To ease recognition of strict qual clauses, we require this routine to be
3162 : : * run after expression preprocessing (i.e., qual canonicalization and JOIN
3163 : : * alias-var expansion).
3164 : : */
3165 : : void
7500 3166 : 16944 : reduce_outer_joins(PlannerInfo *root)
3167 : : {
3168 : : reduce_outer_joins_pass1_state *state1;
3169 : : reduce_outer_joins_pass2_state state2;
3170 : : ListCell *lc;
3171 : :
3172 : : /*
3173 : : * To avoid doing strictness checks on more quals than necessary, we want
3174 : : * to stop descending the jointree as soon as there are no outer joins
3175 : : * below our current point. This consideration forces a two-pass process.
3176 : : * The first pass gathers information about which base rels appear below
3177 : : * each side of each join clause, and about whether there are outer
3178 : : * join(s) below each side of each join clause. The second pass examines
3179 : : * qual clauses and changes join types as it descends the tree.
3180 : : */
1052 3181 : 16944 : state1 = reduce_outer_joins_pass1((Node *) root->parse->jointree);
3182 : :
3183 : : /* planner.c shouldn't have called me if no outer joins */
3184 [ + - - + ]: 16944 : if (state1 == NULL || !state1->contains_outer)
8181 tgl@sss.pgh.pa.us 3185 [ # # ]:UBC 0 : elog(ERROR, "so where are the outer joins?");
3186 : :
1052 tgl@sss.pgh.pa.us 3187 :CBC 16944 : state2.inner_reduced = NULL;
3188 : 16944 : state2.partial_reduced = NIL;
3189 : :
7500 3190 : 16944 : reduce_outer_joins_pass2((Node *) root->parse->jointree,
3191 : : state1, &state2,
3192 : : root, NULL, NIL);
3193 : :
3194 : : /*
3195 : : * If we successfully reduced the strength of any outer joins, we must
3196 : : * remove references to those joins as nulling rels. This is handled as
3197 : : * an additional pass, for simplicity and because we can handle all
3198 : : * fully-reduced joins in a single pass over the parse tree.
3199 : : */
1052 3200 [ + + ]: 16944 : if (!bms_is_empty(state2.inner_reduced))
3201 : : {
3202 : 968 : root->parse = (Query *)
3203 : 968 : remove_nulling_relids((Node *) root->parse,
3204 : 968 : state2.inner_reduced,
3205 : : NULL);
3206 : : /* There could be references in the append_rel_list, too */
3207 : 968 : root->append_rel_list = (List *)
3208 : 968 : remove_nulling_relids((Node *) root->append_rel_list,
3209 : 968 : state2.inner_reduced,
3210 : : NULL);
3211 : : }
3212 : :
3213 : : /*
3214 : : * Partially-reduced full joins have to be done one at a time, since
3215 : : * they'll each need a different setting of except_relids.
3216 : : */
3217 [ + + + + : 16969 : foreach(lc, state2.partial_reduced)
+ + ]
3218 : : {
3219 : 25 : reduce_outer_joins_partial_state *statep = lfirst(lc);
3220 : 25 : Relids full_join_relids = bms_make_singleton(statep->full_join_rti);
3221 : :
3222 : 25 : root->parse = (Query *)
3223 : 25 : remove_nulling_relids((Node *) root->parse,
3224 : : full_join_relids,
3225 : 25 : statep->unreduced_side);
3226 : 25 : root->append_rel_list = (List *)
3227 : 25 : remove_nulling_relids((Node *) root->append_rel_list,
3228 : : full_join_relids,
3229 : 25 : statep->unreduced_side);
3230 : : }
8347 3231 : 16944 : }
3232 : :
3233 : : /*
3234 : : * reduce_outer_joins_pass1 - phase 1 data collection
3235 : : *
3236 : : * Returns a state node describing the given jointree node.
3237 : : */
3238 : : static reduce_outer_joins_pass1_state *
3239 : 96551 : reduce_outer_joins_pass1(Node *jtnode)
3240 : : {
3241 : : reduce_outer_joins_pass1_state *result;
3242 : :
7 michael@paquier.xyz 3243 :GNC 96551 : result = palloc_object(reduce_outer_joins_pass1_state);
8347 tgl@sss.pgh.pa.us 3244 :CBC 96551 : result->relids = NULL;
3245 : 96551 : result->contains_outer = false;
3246 : 96551 : result->sub_states = NIL;
3247 : :
3248 [ - + ]: 96551 : if (jtnode == NULL)
8347 tgl@sss.pgh.pa.us 3249 :UBC 0 : return result;
8347 tgl@sss.pgh.pa.us 3250 [ + + ]:CBC 96551 : if (IsA(jtnode, RangeTblRef))
3251 : : {
3252 : 48159 : int varno = ((RangeTblRef *) jtnode)->rtindex;
3253 : :
3254 : 48159 : result->relids = bms_make_singleton(varno);
3255 : : }
3256 [ + + ]: 48392 : else if (IsA(jtnode, FromExpr))
3257 : : {
3258 : 18610 : FromExpr *f = (FromExpr *) jtnode;
3259 : : ListCell *l;
3260 : :
3261 [ + - + + : 38653 : foreach(l, f->fromlist)
+ + ]
3262 : : {
3263 : : reduce_outer_joins_pass1_state *sub_state;
3264 : :
3265 : 20043 : sub_state = reduce_outer_joins_pass1(lfirst(l));
3266 : 40086 : result->relids = bms_add_members(result->relids,
3267 : 20043 : sub_state->relids);
3268 : 20043 : result->contains_outer |= sub_state->contains_outer;
3269 : 20043 : result->sub_states = lappend(result->sub_states, sub_state);
3270 : : }
3271 : : }
3272 [ + - ]: 29782 : else if (IsA(jtnode, JoinExpr))
3273 : : {
3274 : 29782 : JoinExpr *j = (JoinExpr *) jtnode;
3275 : : reduce_outer_joins_pass1_state *sub_state;
3276 : :
3277 : : /* join's own RT index is not wanted in result->relids */
3278 [ + + ]: 29782 : if (IS_OUTER_JOIN(j->jointype))
3279 : 24472 : result->contains_outer = true;
3280 : :
3281 : 29782 : sub_state = reduce_outer_joins_pass1(j->larg);
3282 : 59564 : result->relids = bms_add_members(result->relids,
3283 : 29782 : sub_state->relids);
3284 : 29782 : result->contains_outer |= sub_state->contains_outer;
3285 : 29782 : result->sub_states = lappend(result->sub_states, sub_state);
3286 : :
3287 : 29782 : sub_state = reduce_outer_joins_pass1(j->rarg);
3288 : 59564 : result->relids = bms_add_members(result->relids,
3289 : 29782 : sub_state->relids);
3290 : 29782 : result->contains_outer |= sub_state->contains_outer;
3291 : 29782 : result->sub_states = lappend(result->sub_states, sub_state);
3292 : : }
3293 : : else
8181 tgl@sss.pgh.pa.us 3294 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
3295 : : (int) nodeTag(jtnode));
8347 tgl@sss.pgh.pa.us 3296 :CBC 96551 : return result;
3297 : : }
3298 : :
3299 : : /*
3300 : : * reduce_outer_joins_pass2 - phase 2 processing
3301 : : *
3302 : : * jtnode: current jointree node
3303 : : * state1: state data collected by phase 1 for this node
3304 : : * state2: where to accumulate info about successfully-reduced joins
3305 : : * root: toplevel planner state
3306 : : * nonnullable_rels: set of base relids forced non-null by upper quals
3307 : : * forced_null_vars: multibitmapset of Vars forced null by upper quals
3308 : : *
3309 : : * Returns info in state2 about outer joins that were successfully simplified.
3310 : : * Joins that were fully reduced to inner joins are all added to
3311 : : * state2->inner_reduced. If a full join is reduced to a left join,
3312 : : * it needs its own entry in state2->partial_reduced, since that will
3313 : : * require custom processing to remove only the correct nullingrel markers.
3314 : : */
3315 : : static void
3316 : 42464 : reduce_outer_joins_pass2(Node *jtnode,
3317 : : reduce_outer_joins_pass1_state *state1,
3318 : : reduce_outer_joins_pass2_state *state2,
3319 : : PlannerInfo *root,
3320 : : Relids nonnullable_rels,
3321 : : List *forced_null_vars)
3322 : : {
3323 : : /*
3324 : : * pass 2 should never descend as far as an empty subnode or base rel,
3325 : : * because it's only called on subtrees marked as contains_outer.
3326 : : */
3327 [ - + ]: 42464 : if (jtnode == NULL)
8181 tgl@sss.pgh.pa.us 3328 [ # # ]:UBC 0 : elog(ERROR, "reached empty jointree");
8347 tgl@sss.pgh.pa.us 3329 [ - + ]:CBC 42464 : if (IsA(jtnode, RangeTblRef))
8181 tgl@sss.pgh.pa.us 3330 [ # # ]:UBC 0 : elog(ERROR, "reached base rel");
8347 tgl@sss.pgh.pa.us 3331 [ + + ]:CBC 42464 : else if (IsA(jtnode, FromExpr))
3332 : : {
3333 : 17682 : FromExpr *f = (FromExpr *) jtnode;
3334 : : ListCell *l;
3335 : : ListCell *s;
3336 : : Relids pass_nonnullable_rels;
3337 : : List *pass_forced_null_vars;
3338 : :
3339 : : /* Scan quals to see if we can add any constraints */
6334 3340 : 17682 : pass_nonnullable_rels = find_nonnullable_rels(f->quals);
3341 : 17682 : pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels,
3342 : : nonnullable_rels);
3343 : 17682 : pass_forced_null_vars = find_forced_null_vars(f->quals);
1127 3344 : 17682 : pass_forced_null_vars = mbms_add_members(pass_forced_null_vars,
3345 : : forced_null_vars);
3346 : : /* And recurse --- but only into interesting subtrees */
1052 3347 [ - + ]: 17682 : Assert(list_length(f->fromlist) == list_length(state1->sub_states));
3348 [ + - + + : 36716 : forboth(l, f->fromlist, s, state1->sub_states)
+ - + + +
+ + - +
+ ]
3349 : : {
3350 : 19034 : reduce_outer_joins_pass1_state *sub_state = lfirst(s);
3351 : :
8347 3352 [ + + ]: 19034 : if (sub_state->contains_outer)
1052 3353 : 17697 : reduce_outer_joins_pass2(lfirst(l), sub_state,
3354 : : state2, root,
3355 : : pass_nonnullable_rels,
3356 : : pass_forced_null_vars);
3357 : : }
6334 3358 : 17682 : bms_free(pass_nonnullable_rels);
3359 : : /* can't so easily clean up var lists, unfortunately */
3360 : : }
8347 3361 [ + - ]: 24782 : else if (IsA(jtnode, JoinExpr))
3362 : : {
3363 : 24782 : JoinExpr *j = (JoinExpr *) jtnode;
3364 : 24782 : int rtindex = j->rtindex;
3365 : 24782 : JoinType jointype = j->jointype;
1052 3366 : 24782 : reduce_outer_joins_pass1_state *left_state = linitial(state1->sub_states);
3367 : 24782 : reduce_outer_joins_pass1_state *right_state = lsecond(state1->sub_states);
3368 : :
3369 : : /* Can we simplify this join? */
8347 3370 [ + + + + : 24782 : switch (jointype)
+ - ]
3371 : : {
6334 3372 : 279 : case JOIN_INNER:
3373 : 279 : break;
8347 3374 : 23102 : case JOIN_LEFT:
3375 [ + + ]: 23102 : if (bms_overlap(nonnullable_rels, right_state->relids))
3376 : 997 : jointype = JOIN_INNER;
3377 : 23102 : break;
3378 : 604 : case JOIN_RIGHT:
3379 [ + + ]: 604 : if (bms_overlap(nonnullable_rels, left_state->relids))
3380 : 40 : jointype = JOIN_INNER;
3381 : 604 : break;
3382 : 548 : case JOIN_FULL:
3383 [ + + ]: 548 : if (bms_overlap(nonnullable_rels, left_state->relids))
3384 : : {
3385 [ + + ]: 12 : if (bms_overlap(nonnullable_rels, right_state->relids))
3386 : 6 : jointype = JOIN_INNER;
3387 : : else
3388 : : {
3389 : 6 : jointype = JOIN_LEFT;
3390 : : /* Also report partial reduction in state2 */
1052 3391 : 6 : report_reduced_full_join(state2, rtindex,
3392 : : right_state->relids);
3393 : : }
3394 : : }
3395 : : else
3396 : : {
8347 3397 [ + + ]: 536 : if (bms_overlap(nonnullable_rels, right_state->relids))
3398 : : {
3399 : 19 : jointype = JOIN_RIGHT;
3400 : : /* Also report partial reduction in state2 */
1052 3401 : 19 : report_reduced_full_join(state2, rtindex,
3402 : : left_state->relids);
3403 : : }
3404 : : }
8347 3405 : 548 : break;
6139 3406 : 249 : case JOIN_SEMI:
3407 : : case JOIN_ANTI:
3408 : :
3409 : : /*
3410 : : * These could only have been introduced by pull_up_sublinks,
3411 : : * so there's no way that upper quals could refer to their
3412 : : * righthand sides, and no point in checking. We don't expect
3413 : : * to see JOIN_RIGHT_SEMI or JOIN_RIGHT_ANTI yet.
3414 : : */
3415 : 249 : break;
8347 tgl@sss.pgh.pa.us 3416 :UBC 0 : default:
6334 3417 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
3418 : : (int) jointype);
3419 : : break;
3420 : : }
3421 : :
3422 : : /*
3423 : : * Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
3424 : : * reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
3425 : : * longer matches the internal ordering of any CoalesceExpr's built to
3426 : : * represent merged join variables. We don't care about that at
3427 : : * present, but be wary of it ...
3428 : : */
6334 tgl@sss.pgh.pa.us 3429 [ + + ]:CBC 24782 : if (jointype == JOIN_RIGHT)
3430 : : {
3431 : : Node *tmparg;
3432 : :
3433 : 583 : tmparg = j->larg;
3434 : 583 : j->larg = j->rarg;
3435 : 583 : j->rarg = tmparg;
3436 : 583 : jointype = JOIN_LEFT;
1052 3437 : 583 : right_state = linitial(state1->sub_states);
3438 : 583 : left_state = lsecond(state1->sub_states);
3439 : : }
3440 : :
3441 : : /*
3442 : : * See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
3443 : : * the join's own quals are strict for any var that was forced null by
3444 : : * higher qual levels. NOTE: there are other ways that we could
3445 : : * detect an anti-join, in particular if we were to check whether Vars
3446 : : * coming from the RHS must be non-null because of table constraints.
3447 : : * That seems complicated and expensive though (in particular, one
3448 : : * would have to be wary of lower outer joins). For the moment this
3449 : : * seems sufficient.
3450 : : */
6334 3451 [ + + ]: 24782 : if (jointype == JOIN_LEFT)
3452 : : {
3453 : : List *nonnullable_vars;
3454 : : Bitmapset *overlap;
3455 : :
3456 : : /* Find Vars in j->quals that must be non-null in joined rows */
1138 3457 : 22694 : nonnullable_vars = find_nonnullable_vars(j->quals);
3458 : :
3459 : : /*
3460 : : * It's not sufficient to check whether nonnullable_vars and
3461 : : * forced_null_vars overlap: we need to know if the overlap
3462 : : * includes any RHS variables.
3463 : : */
1127 3464 : 22694 : overlap = mbms_overlap_sets(nonnullable_vars, forced_null_vars);
3465 [ + + ]: 22694 : if (bms_overlap(overlap, right_state->relids))
6334 3466 : 584 : jointype = JOIN_ANTI;
3467 : : }
3468 : :
3469 : : /*
3470 : : * Apply the jointype change, if any, to both jointree node and RTE.
3471 : : * Also, if we changed an RTE to INNER, add its RTI to inner_reduced.
3472 : : */
6139 3473 [ + + + + ]: 24782 : if (rtindex && jointype != j->jointype)
3474 : : {
7500 3475 : 2216 : RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
3476 : :
8347 3477 [ - + ]: 2216 : Assert(rte->rtekind == RTE_JOIN);
3478 [ - + ]: 2216 : Assert(rte->jointype == j->jointype);
6139 3479 : 2216 : rte->jointype = jointype;
1052 3480 [ + + ]: 2216 : if (jointype == JOIN_INNER)
3481 : 1043 : state2->inner_reduced = bms_add_member(state2->inner_reduced,
3482 : : rtindex);
3483 : : }
6139 3484 : 24782 : j->jointype = jointype;
3485 : :
3486 : : /* Only recurse if there's more to do below here */
8347 3487 [ + + + + ]: 24782 : if (left_state->contains_outer || right_state->contains_outer)
3488 : : {
3489 : : Relids local_nonnullable_rels;
3490 : : List *local_forced_null_vars;
3491 : : Relids pass_nonnullable_rels;
3492 : : List *pass_forced_null_vars;
3493 : :
3494 : : /*
3495 : : * If this join is (now) inner, we can add any constraints its
3496 : : * quals provide to those we got from above. But if it is outer,
3497 : : * we can pass down the local constraints only into the nullable
3498 : : * side, because an outer join never eliminates any rows from its
3499 : : * non-nullable side. Also, there is no point in passing upper
3500 : : * constraints into the nullable side, since if there were any
3501 : : * we'd have been able to reduce the join. (In the case of upper
3502 : : * forced-null constraints, we *must not* pass them into the
3503 : : * nullable side --- they either applied here, or not.) The upshot
3504 : : * is that we pass either the local or the upper constraints,
3505 : : * never both, to the children of an outer join.
3506 : : *
3507 : : * Note that a SEMI join works like an inner join here: it's okay
3508 : : * to pass down both local and upper constraints. (There can't be
3509 : : * any upper constraints affecting its inner side, but it's not
3510 : : * worth having a separate code path to avoid passing them.)
3511 : : *
3512 : : * At a FULL join we just punt and pass nothing down --- is it
3513 : : * possible to be smarter?
3514 : : */
8346 3515 [ + + ]: 7789 : if (jointype != JOIN_FULL)
3516 : : {
6334 3517 : 7721 : local_nonnullable_rels = find_nonnullable_rels(j->quals);
3518 : 7721 : local_forced_null_vars = find_forced_null_vars(j->quals);
5435 3519 [ + + + + ]: 7721 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3520 : : {
3521 : : /* OK to merge upper and local constraints */
6334 3522 : 508 : local_nonnullable_rels = bms_add_members(local_nonnullable_rels,
3523 : : nonnullable_rels);
1127 3524 : 508 : local_forced_null_vars = mbms_add_members(local_forced_null_vars,
3525 : : forced_null_vars);
3526 : : }
3527 : : }
3528 : : else
3529 : : {
3530 : : /* no use in calculating these */
6334 3531 : 68 : local_nonnullable_rels = NULL;
3532 : 68 : local_forced_null_vars = NIL;
3533 : : }
3534 : :
8347 3535 [ + + ]: 7789 : if (left_state->contains_outer)
3536 : : {
5435 3537 [ + + + + ]: 7418 : if (jointype == JOIN_INNER || jointype == JOIN_SEMI)
3538 : : {
3539 : : /* pass union of local and upper constraints */
6334 3540 : 402 : pass_nonnullable_rels = local_nonnullable_rels;
3541 : 402 : pass_forced_null_vars = local_forced_null_vars;
3542 : : }
5365 bruce@momjian.us 3543 [ + + ]: 7016 : else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
3544 : : {
3545 : : /* can't pass local constraints to non-nullable side */
6334 tgl@sss.pgh.pa.us 3546 : 6962 : pass_nonnullable_rels = nonnullable_rels;
3547 : 6962 : pass_forced_null_vars = forced_null_vars;
3548 : : }
3549 : : else
3550 : : {
3551 : : /* no constraints pass through JOIN_FULL */
3552 : 54 : pass_nonnullable_rels = NULL;
3553 : 54 : pass_forced_null_vars = NIL;
3554 : : }
1052 3555 : 7418 : reduce_outer_joins_pass2(j->larg, left_state,
3556 : : state2, root,
3557 : : pass_nonnullable_rels,
3558 : : pass_forced_null_vars);
3559 : : }
3560 : :
8347 3561 [ + + ]: 7789 : if (right_state->contains_outer)
3562 : : {
3101 3563 [ + + ]: 405 : if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
3564 : : {
3565 : : /* pass appropriate constraints, per comment above */
6334 3566 : 391 : pass_nonnullable_rels = local_nonnullable_rels;
3567 : 391 : pass_forced_null_vars = local_forced_null_vars;
3568 : : }
3569 : : else
3570 : : {
3571 : : /* no constraints pass through JOIN_FULL */
3572 : 14 : pass_nonnullable_rels = NULL;
3573 : 14 : pass_forced_null_vars = NIL;
3574 : : }
1052 3575 : 405 : reduce_outer_joins_pass2(j->rarg, right_state,
3576 : : state2, root,
3577 : : pass_nonnullable_rels,
3578 : : pass_forced_null_vars);
3579 : : }
6334 3580 : 7789 : bms_free(local_nonnullable_rels);
3581 : : }
3582 : : }
3583 : : else
8181 tgl@sss.pgh.pa.us 3584 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
3585 : : (int) nodeTag(jtnode));
8347 tgl@sss.pgh.pa.us 3586 :CBC 42464 : }
3587 : :
3588 : : /* Helper for reduce_outer_joins_pass2 */
3589 : : static void
1052 3590 : 25 : report_reduced_full_join(reduce_outer_joins_pass2_state *state2,
3591 : : int rtindex, Relids relids)
3592 : : {
3593 : : reduce_outer_joins_partial_state *statep;
3594 : :
7 michael@paquier.xyz 3595 :GNC 25 : statep = palloc_object(reduce_outer_joins_partial_state);
1052 tgl@sss.pgh.pa.us 3596 :CBC 25 : statep->full_join_rti = rtindex;
3597 : 25 : statep->unreduced_side = relids;
3598 : 25 : state2->partial_reduced = lappend(state2->partial_reduced, statep);
3599 : 25 : }
3600 : :
3601 : :
3602 : : /*
3603 : : * remove_useless_result_rtes
3604 : : * Attempt to remove RTE_RESULT RTEs from the join tree.
3605 : : * Also, elide single-child FromExprs where possible.
3606 : : *
3607 : : * We can remove RTE_RESULT entries from the join tree using the knowledge
3608 : : * that RTE_RESULT returns exactly one row and has no output columns. Hence,
3609 : : * if one is inner-joined to anything else, we can delete it. Optimizations
3610 : : * are also possible for some outer-join cases, as detailed below.
3611 : : *
3612 : : * This pass also replaces single-child FromExprs with their child node
3613 : : * where possible. It's appropriate to do that here and not earlier because
3614 : : * RTE_RESULT removal might reduce a multiple-child FromExpr to have only one
3615 : : * child. We can remove such a FromExpr if its quals are empty, or if it's
3616 : : * semantically valid to merge the quals into those of the parent node.
3617 : : * While removing unnecessary join tree nodes has some micro-efficiency value,
3618 : : * the real reason to do this is to eliminate cases where the nullable side of
3619 : : * an outer join node is a FromExpr whose single child is another outer join.
3620 : : * To correctly determine whether the two outer joins can commute,
3621 : : * deconstruct_jointree() must treat any quals of such a FromExpr as being
3622 : : * degenerate quals of the upper outer join. The best way to do that is to
3623 : : * make them actually *be* quals of the upper join, by dropping the FromExpr
3624 : : * and hoisting the quals up into the upper join's quals. (Note that there is
3625 : : * no hazard when the intermediate FromExpr has multiple children, since then
3626 : : * it represents an inner join that cannot commute with the upper outer join.)
3627 : : * As long as we have to do that, we might as well elide such FromExprs
3628 : : * everywhere.
3629 : : *
3630 : : * Some of these optimizations depend on recognizing empty (constant-true)
3631 : : * quals for FromExprs and JoinExprs. That makes it useful to apply this
3632 : : * optimization pass after expression preprocessing, since that will have
3633 : : * eliminated constant-true quals, allowing more cases to be recognized as
3634 : : * optimizable. What's more, the usual reason for an RTE_RESULT to be present
3635 : : * is that we pulled up a subquery or VALUES clause, thus very possibly
3636 : : * replacing Vars with constants, making it more likely that a qual can be
3637 : : * reduced to constant true. Also, because some optimizations depend on
3638 : : * the outer-join type, it's best to have done reduce_outer_joins() first.
3639 : : *
3640 : : * A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
3641 : : * process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
3642 : : * we must not reduce the phrels set to empty. If that would happen, and
3643 : : * the RTE_RESULT is an immediate child of an outer join, we have to give up
3644 : : * and not remove the RTE_RESULT: there is noplace else to evaluate the
3645 : : * PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
3646 : : * columns.) But if the RTE_RESULT is an immediate child of an inner join,
3647 : : * we can usually change the PlaceHolderVar's phrels so as to evaluate it at
3648 : : * the inner join instead. This is OK because we really only care that PHVs
3649 : : * are evaluated above or below the correct outer joins. We can't, however,
3650 : : * postpone the evaluation of a PHV to above where it is used; so there are
3651 : : * some checks below on whether output PHVs are laterally referenced in the
3652 : : * other join input rel(s).
3653 : : *
3654 : : * We used to try to do this work as part of pull_up_subqueries() where the
3655 : : * potentially-optimizable cases get introduced; but it's way simpler, and
3656 : : * more effective, to do it separately.
3657 : : */
3658 : : void
2515 3659 : 115224 : remove_useless_result_rtes(PlannerInfo *root)
3660 : : {
1052 3661 : 115224 : Relids dropped_outer_joins = NULL;
3662 : : ListCell *cell;
3663 : :
3664 : : /* Top level of jointree must always be a FromExpr */
2515 3665 [ - + ]: 115224 : Assert(IsA(root->parse->jointree, FromExpr));
3666 : : /* Recurse ... */
3667 : 230448 : root->parse->jointree = (FromExpr *)
1052 3668 : 115224 : remove_useless_results_recurse(root,
3669 : 115224 : (Node *) root->parse->jointree,
3670 : : NULL,
3671 : : &dropped_outer_joins);
3672 : : /* We should still have a FromExpr */
2515 3673 [ - + ]: 115224 : Assert(IsA(root->parse->jointree, FromExpr));
3674 : :
3675 : : /*
3676 : : * If we removed any outer-join nodes from the jointree, run around and
3677 : : * remove references to those joins as nulling rels. (There could be such
3678 : : * references in PHVs that we pulled up out of the original subquery that
3679 : : * the RESULT rel replaced. This is kosher on the grounds that we now
3680 : : * know that such an outer join wouldn't really have nulled anything.) We
3681 : : * don't do this during the main recursion, for simplicity and because we
3682 : : * can handle all such joins in a single pass over the parse tree.
3683 : : */
1052 3684 [ + + ]: 115224 : if (!bms_is_empty(dropped_outer_joins))
3685 : : {
3686 : 30 : root->parse = (Query *)
3687 : 30 : remove_nulling_relids((Node *) root->parse,
3688 : : dropped_outer_joins,
3689 : : NULL);
3690 : : /* There could be references in the append_rel_list, too */
3691 : 30 : root->append_rel_list = (List *)
3692 : 30 : remove_nulling_relids((Node *) root->append_rel_list,
3693 : : dropped_outer_joins,
3694 : : NULL);
3695 : : }
3696 : :
3697 : : /*
3698 : : * Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
3699 : : * must do that for any RTE_RESULT that we just removed. But one for a
3700 : : * RTE that we did not remove can be dropped anyway: since the RTE has
3701 : : * only one possible output row, there is no need for EPQ to mark and
3702 : : * restore that row.
3703 : : *
3704 : : * It's necessary, not optional, to remove the PlanRowMark for a surviving
3705 : : * RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
3706 : : * RTE_RESULT, which the executor has no support for.
3707 : : */
2347 3708 [ + + + + : 116213 : foreach(cell, root->rowMarks)
+ + ]
3709 : : {
2515 3710 : 989 : PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
3711 : :
3712 [ + + ]: 989 : if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
2347 3713 : 420 : root->rowMarks = foreach_delete_current(root->rowMarks, cell);
3714 : : }
2515 3715 : 115224 : }
3716 : :
3717 : : /*
3718 : : * remove_useless_results_recurse
3719 : : * Recursive guts of remove_useless_result_rtes.
3720 : : *
3721 : : * This recursively processes the jointree and returns a modified jointree.
3722 : : * In addition, the RT indexes of any removed outer-join nodes are added to
3723 : : * *dropped_outer_joins.
3724 : : *
3725 : : * jtnode is the current jointree node. If it could be valid to merge
3726 : : * its quals into those of the parent node, parent_quals should point to
3727 : : * the parent's quals list; otherwise, pass NULL for parent_quals.
3728 : : * (Note that in some cases, parent_quals points to the quals of a parent
3729 : : * more than one level up in the tree.)
3730 : : */
3731 : : static Node *
1052 3732 : 299018 : remove_useless_results_recurse(PlannerInfo *root, Node *jtnode,
3733 : : Node **parent_quals,
3734 : : Relids *dropped_outer_joins)
3735 : : {
2515 3736 [ - + ]: 299018 : Assert(jtnode != NULL);
3737 [ + + ]: 299018 : if (IsA(jtnode, RangeTblRef))
3738 : : {
3739 : : /* Can't immediately do anything with a RangeTblRef */
3740 : : }
3741 [ + + ]: 150369 : else if (IsA(jtnode, FromExpr))
3742 : : {
3743 : 118700 : FromExpr *f = (FromExpr *) jtnode;
3744 : 118700 : Relids result_relids = NULL;
3745 : : ListCell *cell;
3746 : :
3747 : : /*
3748 : : * We can drop RTE_RESULT rels from the fromlist so long as at least
3749 : : * one child remains, since joining to a one-row table changes
3750 : : * nothing. (But we can't drop a RTE_RESULT that computes PHV(s) that
3751 : : * are needed by some sibling. The cleanup transformation below would
3752 : : * reassign the PHVs to be computed at the join, which is too late for
3753 : : * the sibling's use.) The easiest way to mechanize this rule is to
3754 : : * modify the list in-place.
3755 : : */
2347 3756 [ + - + + : 239156 : foreach(cell, f->fromlist)
+ + ]
3757 : : {
2515 3758 : 120456 : Node *child = (Node *) lfirst(cell);
3759 : : int varno;
3760 : :
3761 : : /* Recursively transform child, allowing it to push up quals ... */
1052 3762 : 120456 : child = remove_useless_results_recurse(root, child,
3763 : : &f->quals,
3764 : : dropped_outer_joins);
3765 : : /* ... and stick it back into the tree */
2515 3766 : 120456 : lfirst(cell) = child;
3767 : :
3768 : : /*
3769 : : * If it's an RTE_RESULT with at least one sibling, and no sibling
3770 : : * references dependent PHVs, we can drop it. We don't yet know
3771 : : * what the inner join's final relid set will be, so postpone
3772 : : * cleanup of PHVs etc till after this loop.
3773 : : */
3774 [ + + + + ]: 123288 : if (list_length(f->fromlist) > 1 &&
2195 3775 : 2832 : (varno = get_result_relid(root, child)) != 0 &&
3776 [ + + ]: 173 : !find_dependent_phvs_in_jointree(root, (Node *) f, varno))
3777 : : {
2347 3778 : 161 : f->fromlist = foreach_delete_current(f->fromlist, cell);
2515 3779 : 161 : result_relids = bms_add_member(result_relids, varno);
3780 : : }
3781 : : }
3782 : :
3783 : : /*
3784 : : * Clean up if we dropped any RTE_RESULT RTEs. This is a bit
3785 : : * inefficient if there's more than one, but it seems better to
3786 : : * optimize the support code for the single-relid case.
3787 : : */
3788 [ + + ]: 118700 : if (result_relids)
3789 : : {
3790 : 155 : int varno = -1;
3791 : :
3792 [ + + ]: 316 : while ((varno = bms_next_member(result_relids, varno)) >= 0)
3793 : 161 : remove_result_refs(root, varno, (Node *) f);
3794 : : }
3795 : :
3796 : : /*
3797 : : * If the FromExpr now has only one child, see if we can elide it.
3798 : : * This is always valid if there are no quals, except at the top of
3799 : : * the jointree (since Query.jointree is required to point to a
3800 : : * FromExpr). Otherwise, we can do it if we can push the quals up to
3801 : : * the parent node.
3802 : : *
3803 : : * Note: while it would not be terribly hard to generalize this
3804 : : * transformation to merge multi-child FromExprs into their parent
3805 : : * FromExpr, that risks making the parent join too expensive to plan.
3806 : : * We leave it to later processing to decide heuristically whether
3807 : : * that's a good idea. Pulling up a single child is always OK,
3808 : : * however.
3809 : : */
1052 3810 [ + + ]: 118700 : if (list_length(f->fromlist) == 1 &&
3811 [ + + ]: 117728 : f != root->parse->jointree &&
3812 [ + + + + ]: 3362 : (f->quals == NULL || parent_quals != NULL))
3813 : : {
3814 : : /*
3815 : : * Merge any quals up to parent. They should be in implicit-AND
3816 : : * format by now, so we just need to concatenate lists. Put the
3817 : : * child quals at the front, on the grounds that they should
3818 : : * nominally be evaluated earlier.
3819 : : */
3820 [ + + ]: 1401 : if (f->quals != NULL)
3821 : 715 : *parent_quals = (Node *)
3822 : 715 : list_concat(castNode(List, f->quals),
3823 : 715 : castNode(List, *parent_quals));
2515 3824 : 1401 : return (Node *) linitial(f->fromlist);
3825 : : }
3826 : : }
3827 [ + - ]: 31669 : else if (IsA(jtnode, JoinExpr))
3828 : : {
3829 : 31669 : JoinExpr *j = (JoinExpr *) jtnode;
3830 : : int varno;
3831 : :
3832 : : /*
3833 : : * First, recurse. We can absorb pushed-up FromExpr quals from either
3834 : : * child into this node if the jointype is INNER, since then this is
3835 : : * equivalent to a FromExpr. When the jointype is LEFT, we can absorb
3836 : : * quals from the RHS child into the current node, as they're
3837 : : * essentially degenerate quals of the outer join. Moreover, if we've
3838 : : * been passed down a parent_quals pointer then we can allow quals of
3839 : : * the LHS child to be absorbed into the parent. (This is important
3840 : : * to ensure we remove single-child FromExprs immediately below
3841 : : * commutable left joins.) For other jointypes, we can't move child
3842 : : * quals up, or at least there's no particular reason to.
3843 : : */
1052 3844 : 31669 : j->larg = remove_useless_results_recurse(root, j->larg,
3845 [ + + ]: 31669 : (j->jointype == JOIN_INNER) ?
3846 : : &j->quals :
911 3847 : 25066 : (j->jointype == JOIN_LEFT) ?
3848 [ + + ]: 25066 : parent_quals : NULL,
3849 : : dropped_outer_joins);
1052 3850 : 31669 : j->rarg = remove_useless_results_recurse(root, j->rarg,
3851 [ + + ]: 31669 : (j->jointype == JOIN_INNER ||
3852 [ + + ]: 25066 : j->jointype == JOIN_LEFT) ?
3853 : : &j->quals : NULL,
3854 : : dropped_outer_joins);
3855 : :
3856 : : /* Apply join-type-specific optimization rules */
2515 3857 [ + + + + : 31669 : switch (j->jointype)
- ]
3858 : : {
3859 : 6603 : case JOIN_INNER:
3860 : :
3861 : : /*
3862 : : * An inner join is equivalent to a FromExpr, so if either
3863 : : * side was simplified to an RTE_RESULT rel, we can replace
3864 : : * the join with a FromExpr with just the other side.
3865 : : * Furthermore, we can elide that FromExpr according to the
3866 : : * same rules as above.
3867 : : *
3868 : : * Just as in the FromExpr case, we can't simplify if the
3869 : : * other input rel references any PHVs that are marked as to
3870 : : * be evaluated at the RTE_RESULT rel, because we can't
3871 : : * postpone their evaluation in that case. But we only have
3872 : : * to check this in cases where it's syntactically legal for
3873 : : * the other input to have a LATERAL reference to the
3874 : : * RTE_RESULT rel. Only RHSes of inner and left joins are
3875 : : * allowed to have such refs.
3876 : : */
2195 3877 [ + + ]: 6603 : if ((varno = get_result_relid(root, j->larg)) != 0 &&
3878 [ + - ]: 53 : !find_dependent_phvs_in_jointree(root, j->rarg, varno))
3879 : : {
2515 3880 : 53 : remove_result_refs(root, varno, j->rarg);
1052 3881 [ + + + + ]: 53 : if (j->quals != NULL && parent_quals == NULL)
2515 3882 : 6 : jtnode = (Node *)
3883 : 6 : makeFromExpr(list_make1(j->rarg), j->quals);
3884 : : else
3885 : : {
3886 : : /* Merge any quals up to parent */
1052 3887 [ + + ]: 47 : if (j->quals != NULL)
3888 : 35 : *parent_quals = (Node *)
3889 : 35 : list_concat(castNode(List, j->quals),
3890 : 35 : castNode(List, *parent_quals));
2515 3891 : 47 : jtnode = j->rarg;
3892 : : }
3893 : : }
3894 [ + + ]: 6550 : else if ((varno = get_result_relid(root, j->rarg)) != 0)
3895 : : {
3896 : 400 : remove_result_refs(root, varno, j->larg);
1052 3897 [ + + + + ]: 400 : if (j->quals != NULL && parent_quals == NULL)
2515 3898 : 6 : jtnode = (Node *)
3899 : 6 : makeFromExpr(list_make1(j->larg), j->quals);
3900 : : else
3901 : : {
3902 : : /* Merge any quals up to parent */
1052 3903 [ + + ]: 394 : if (j->quals != NULL)
3904 : 258 : *parent_quals = (Node *)
3905 : 258 : list_concat(castNode(List, j->quals),
3906 : 258 : castNode(List, *parent_quals));
2515 3907 : 394 : jtnode = j->larg;
3908 : : }
3909 : : }
3910 : 6603 : break;
3911 : 22110 : case JOIN_LEFT:
3912 : :
3913 : : /*
3914 : : * We can simplify this case if the RHS is an RTE_RESULT, with
3915 : : * two different possibilities:
3916 : : *
3917 : : * If the qual is empty (JOIN ON TRUE), then the join can be
3918 : : * strength-reduced to a plain inner join, since each LHS row
3919 : : * necessarily has exactly one join partner. So we can always
3920 : : * discard the RHS, much as in the JOIN_INNER case above.
3921 : : * (Again, the LHS could not contain a lateral reference to
3922 : : * the RHS.)
3923 : : *
3924 : : * Otherwise, it's still true that each LHS row should be
3925 : : * returned exactly once, and since the RHS returns no columns
3926 : : * (unless there are PHVs that have to be evaluated there), we
3927 : : * don't much care if it's null-extended or not. So in this
3928 : : * case also, we can just ignore the qual and discard the left
3929 : : * join.
3930 : : */
3931 [ + + ]: 22110 : if ((varno = get_result_relid(root, j->rarg)) != 0 &&
3932 [ + + ]: 75 : (j->quals == NULL ||
2195 3933 [ - + ]: 45 : !find_dependent_phvs(root, varno)))
3934 : : {
2515 3935 : 30 : remove_result_refs(root, varno, j->larg);
1052 3936 : 30 : *dropped_outer_joins = bms_add_member(*dropped_outer_joins,
3937 : : j->rtindex);
2515 3938 : 30 : jtnode = j->larg;
3939 : : }
3940 : 22110 : break;
3941 : 1637 : case JOIN_SEMI:
3942 : :
3943 : : /*
3944 : : * We may simplify this case if the RHS is an RTE_RESULT; the
3945 : : * join qual becomes effectively just a filter qual for the
3946 : : * LHS, since we should either return the LHS row or not. The
3947 : : * filter clause must go into a new FromExpr if we can't push
3948 : : * it up to the parent.
3949 : : *
3950 : : * There is a fine point about PHVs that are supposed to be
3951 : : * evaluated at the RHS. Such PHVs could only appear in the
3952 : : * semijoin's qual, since the rest of the query cannot
3953 : : * reference any outputs of the semijoin's RHS. Therefore,
3954 : : * they can't actually go to null before being examined, and
3955 : : * it'd be OK to just remove the PHV wrapping. We don't have
3956 : : * infrastructure for that, but remove_result_refs() will
3957 : : * relabel them as to be evaluated at the LHS, which is fine.
3958 : : *
3959 : : * Also, we don't need to worry about removing traces of the
3960 : : * join's rtindex, since it hasn't got one.
3961 : : */
3962 [ + + ]: 1637 : if ((varno = get_result_relid(root, j->rarg)) != 0)
3963 : : {
1052 3964 [ - + ]: 18 : Assert(j->rtindex == 0);
2515 3965 : 18 : remove_result_refs(root, varno, j->larg);
1052 3966 [ + - - + ]: 18 : if (j->quals != NULL && parent_quals == NULL)
2515 tgl@sss.pgh.pa.us 3967 :UBC 0 : jtnode = (Node *)
3968 : 0 : makeFromExpr(list_make1(j->larg), j->quals);
3969 : : else
3970 : : {
3971 : : /* Merge any quals up to parent */
1052 tgl@sss.pgh.pa.us 3972 [ + - ]:CBC 18 : if (j->quals != NULL)
3973 : 18 : *parent_quals = (Node *)
3974 : 18 : list_concat(castNode(List, j->quals),
3975 : 18 : castNode(List, *parent_quals));
2515 3976 : 18 : jtnode = j->larg;
3977 : : }
3978 : : }
3979 : 1637 : break;
3980 : 1319 : case JOIN_FULL:
3981 : : case JOIN_ANTI:
3982 : : /* We have no special smarts for these cases */
3983 : 1319 : break;
2515 tgl@sss.pgh.pa.us 3984 :UBC 0 : default:
3985 : : /* Note: JOIN_RIGHT should be gone at this point */
3986 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
3987 : : (int) j->jointype);
3988 : : break;
3989 : : }
3990 : : }
3991 : : else
3992 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
3993 : : (int) nodeTag(jtnode));
2515 tgl@sss.pgh.pa.us 3994 :CBC 297617 : return jtnode;
3995 : : }
3996 : :
3997 : : /*
3998 : : * get_result_relid
3999 : : * If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
4000 : : * otherwise return 0.
4001 : : */
4002 : : static int
4003 : 39732 : get_result_relid(PlannerInfo *root, Node *jtnode)
4004 : : {
4005 : : int varno;
4006 : :
4007 [ + + ]: 39732 : if (!IsA(jtnode, RangeTblRef))
4008 : 3383 : return 0;
4009 : 36349 : varno = ((RangeTblRef *) jtnode)->rtindex;
4010 [ + + ]: 36349 : if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
4011 : 35630 : return 0;
4012 : 719 : return varno;
4013 : : }
4014 : :
4015 : : /*
4016 : : * remove_result_refs
4017 : : * Helper routine for dropping an unneeded RTE_RESULT RTE.
4018 : : *
4019 : : * This doesn't physically remove the RTE from the jointree, because that's
4020 : : * more easily handled in remove_useless_results_recurse. What it does do
4021 : : * is the necessary cleanup in the rest of the tree: we must adjust any PHVs
4022 : : * that may reference the RTE. Be sure to call this at a point where the
4023 : : * jointree is valid (no disconnected nodes).
4024 : : *
4025 : : * Note that we don't need to process the append_rel_list, since RTEs
4026 : : * referenced directly in the jointree won't be appendrel members.
4027 : : *
4028 : : * varno is the RTE_RESULT's relid.
4029 : : * newjtloc is the jointree location at which any PHVs referencing the
4030 : : * RTE_RESULT should be evaluated instead.
4031 : : */
4032 : : static void
4033 : 662 : remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
4034 : : {
4035 : : /* Fix up PlaceHolderVars as needed */
4036 : : /* If there are no PHVs anywhere, we can skip this bit */
4037 [ + + ]: 662 : if (root->glob->lastPHId != 0)
4038 : : {
4039 : : Relids subrelids;
4040 : :
1052 4041 : 140 : subrelids = get_relids_in_jointree(newjtloc, true, false);
2515 4042 [ - + ]: 140 : Assert(!bms_is_empty(subrelids));
4043 : 140 : substitute_phv_relids((Node *) root->parse, varno, subrelids);
1091 4044 : 140 : fix_append_rel_relids(root, varno, subrelids);
4045 : : }
4046 : :
4047 : : /*
4048 : : * We also need to remove any PlanRowMark referencing the RTE, but we
4049 : : * postpone that work until we return to remove_useless_result_rtes.
4050 : : */
2515 4051 : 662 : }
4052 : :
4053 : :
4054 : : /*
4055 : : * find_dependent_phvs - are there any PlaceHolderVars whose relids are
4056 : : * exactly the given varno?
4057 : : *
4058 : : * find_dependent_phvs should be used when we want to see if there are
4059 : : * any such PHVs anywhere in the Query. Another use-case is to see if
4060 : : * a subtree of the join tree contains such PHVs; but for that, we have
4061 : : * to look not only at the join tree nodes themselves but at the
4062 : : * referenced RTEs. For that, use find_dependent_phvs_in_jointree.
4063 : : */
4064 : :
4065 : : typedef struct
4066 : : {
4067 : : Relids relids;
4068 : : int sublevels_up;
4069 : : } find_dependent_phvs_context;
4070 : :
4071 : : static bool
4072 : 1200 : find_dependent_phvs_walker(Node *node,
4073 : : find_dependent_phvs_context *context)
4074 : : {
4075 [ + + ]: 1200 : if (node == NULL)
4076 : 282 : return false;
4077 [ + + ]: 918 : if (IsA(node, PlaceHolderVar))
4078 : : {
4079 : 78 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4080 : :
4081 [ + - + + ]: 156 : if (phv->phlevelsup == context->sublevels_up &&
4082 : 78 : bms_equal(context->relids, phv->phrels))
4083 : 57 : return true;
4084 : : /* fall through to examine children */
4085 : : }
4086 [ + + ]: 861 : if (IsA(node, Query))
4087 : : {
4088 : : /* Recurse into subselects */
4089 : : bool result;
4090 : :
4091 : 24 : context->sublevels_up++;
4092 : 24 : result = query_tree_walker((Query *) node,
4093 : : find_dependent_phvs_walker,
4094 : : context, 0);
4095 : 24 : context->sublevels_up--;
4096 : 24 : return result;
4097 : : }
4098 : : /* Shouldn't need to handle most planner auxiliary nodes here */
4099 [ - + ]: 837 : Assert(!IsA(node, SpecialJoinInfo));
4100 [ - + ]: 837 : Assert(!IsA(node, PlaceHolderInfo));
4101 [ - + ]: 837 : Assert(!IsA(node, MinMaxAggInfo));
4102 : :
384 peter@eisentraut.org 4103 : 837 : return expression_tree_walker(node, find_dependent_phvs_walker, context);
4104 : : }
4105 : :
4106 : : static bool
2195 tgl@sss.pgh.pa.us 4107 : 45 : find_dependent_phvs(PlannerInfo *root, int varno)
4108 : : {
4109 : : find_dependent_phvs_context context;
4110 : :
4111 : : /* If there are no PHVs anywhere, we needn't work hard */
4112 [ - + ]: 45 : if (root->glob->lastPHId == 0)
2195 tgl@sss.pgh.pa.us 4113 :UBC 0 : return false;
4114 : :
2515 tgl@sss.pgh.pa.us 4115 :CBC 45 : context.relids = bms_make_singleton(varno);
4116 : 45 : context.sublevels_up = 0;
4117 : :
384 peter@eisentraut.org 4118 [ + - ]: 45 : if (query_tree_walker(root->parse, find_dependent_phvs_walker, &context, 0))
1052 tgl@sss.pgh.pa.us 4119 : 45 : return true;
4120 : : /* The append_rel_list could be populated already, so check it too */
1052 tgl@sss.pgh.pa.us 4121 [ # # ]:UBC 0 : if (expression_tree_walker((Node *) root->append_rel_list,
4122 : : find_dependent_phvs_walker,
4123 : : &context))
4124 : 0 : return true;
4125 : 0 : return false;
4126 : : }
4127 : :
4128 : : static bool
2195 tgl@sss.pgh.pa.us 4129 :CBC 226 : find_dependent_phvs_in_jointree(PlannerInfo *root, Node *node, int varno)
4130 : : {
4131 : : find_dependent_phvs_context context;
4132 : : Relids subrelids;
4133 : : int relid;
4134 : :
4135 : : /* If there are no PHVs anywhere, we needn't work hard */
4136 [ + + ]: 226 : if (root->glob->lastPHId == 0)
4137 : 193 : return false;
4138 : :
4139 : 33 : context.relids = bms_make_singleton(varno);
4140 : 33 : context.sublevels_up = 0;
4141 : :
4142 : : /*
4143 : : * See if the jointree fragment itself contains references (in join quals)
4144 : : */
4145 [ - + ]: 33 : if (find_dependent_phvs_walker(node, &context))
2195 tgl@sss.pgh.pa.us 4146 :UBC 0 : return true;
4147 : :
4148 : : /*
4149 : : * Otherwise, identify the set of referenced RTEs (we can ignore joins,
4150 : : * since they should be flattened already, so their join alias lists no
4151 : : * longer matter), and tediously check each RTE. We can ignore RTEs that
4152 : : * are not marked LATERAL, though, since they couldn't possibly contain
4153 : : * any cross-references to other RTEs.
4154 : : */
1052 tgl@sss.pgh.pa.us 4155 :CBC 33 : subrelids = get_relids_in_jointree(node, false, false);
2195 4156 : 33 : relid = -1;
4157 [ + + ]: 72 : while ((relid = bms_next_member(subrelids, relid)) >= 0)
4158 : : {
4159 : 51 : RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
4160 : :
4161 [ + + + - ]: 63 : if (rte->lateral &&
384 peter@eisentraut.org 4162 : 12 : range_table_entry_walker(rte, find_dependent_phvs_walker, &context, 0))
2195 tgl@sss.pgh.pa.us 4163 : 12 : return true;
4164 : : }
4165 : :
4166 : 21 : return false;
4167 : : }
4168 : :
4169 : : /*
4170 : : * substitute_phv_relids - adjust PlaceHolderVar relid sets after pulling up
4171 : : * a subquery or removing an RTE_RESULT jointree item
4172 : : *
4173 : : * Find any PlaceHolderVar nodes in the given tree that reference the
4174 : : * pulled-up relid, and change them to reference the replacement relid(s).
4175 : : *
4176 : : * NOTE: although this has the form of a walker, we cheat and modify the
4177 : : * nodes in-place. This should be OK since the tree was copied by
4178 : : * pullup_replace_vars earlier. Avoid scribbling on the original values of
4179 : : * the bitmapsets, though, because expression_tree_mutator doesn't copy those.
4180 : : */
4181 : :
4182 : : typedef struct
4183 : : {
4184 : : int varno;
4185 : : int sublevels_up;
4186 : : Relids subrelids;
4187 : : } substitute_phv_relids_context;
4188 : :
4189 : : static bool
2515 4190 : 136347 : substitute_phv_relids_walker(Node *node,
4191 : : substitute_phv_relids_context *context)
4192 : : {
6334 4193 [ + + ]: 136347 : if (node == NULL)
4194 : 51759 : return false;
6266 4195 [ + + ]: 84588 : if (IsA(node, PlaceHolderVar))
4196 : : {
4197 : 3846 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4198 : :
5016 4199 [ + + + + ]: 7676 : if (phv->phlevelsup == context->sublevels_up &&
4200 : 3830 : bms_is_member(context->varno, phv->phrels))
4201 : : {
6266 4202 : 5492 : phv->phrels = bms_union(phv->phrels,
4203 : 2746 : context->subrelids);
4204 : 2746 : phv->phrels = bms_del_member(phv->phrels,
4205 : : context->varno);
4206 : : /* Assert we haven't broken the PHV */
2515 4207 [ - + ]: 2746 : Assert(!bms_is_empty(phv->phrels));
4208 : : }
4209 : : /* fall through to examine children */
4210 : : }
5016 4211 [ + + ]: 84588 : if (IsA(node, Query))
4212 : : {
4213 : : /* Recurse into subselects */
4214 : : bool result;
4215 : :
4216 : 2234 : context->sublevels_up++;
4217 : 2234 : result = query_tree_walker((Query *) node,
4218 : : substitute_phv_relids_walker,
4219 : : context, 0);
4220 : 2234 : context->sublevels_up--;
4221 : 2234 : return result;
4222 : : }
4223 : : /* Shouldn't need to handle planner auxiliary nodes here */
6265 4224 [ - + ]: 82354 : Assert(!IsA(node, SpecialJoinInfo));
4225 [ - + ]: 82354 : Assert(!IsA(node, AppendRelInfo));
4226 [ - + ]: 82354 : Assert(!IsA(node, PlaceHolderInfo));
5522 4227 [ - + ]: 82354 : Assert(!IsA(node, MinMaxAggInfo));
4228 : :
384 peter@eisentraut.org 4229 : 82354 : return expression_tree_walker(node, substitute_phv_relids_walker, context);
4230 : : }
4231 : :
4232 : : static void
2515 tgl@sss.pgh.pa.us 4233 : 1218 : substitute_phv_relids(Node *node, int varno, Relids subrelids)
4234 : : {
4235 : : substitute_phv_relids_context context;
4236 : :
6334 4237 : 1218 : context.varno = varno;
5016 4238 : 1218 : context.sublevels_up = 0;
6334 4239 : 1218 : context.subrelids = subrelids;
4240 : :
4241 : : /*
4242 : : * Must be prepared to start with a Query or a bare expression tree.
4243 : : */
4244 : 1218 : query_or_expression_tree_walker(node,
4245 : : substitute_phv_relids_walker,
4246 : : &context,
4247 : : 0);
8367 4248 : 1218 : }
4249 : :
4250 : : /*
4251 : : * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
4252 : : *
4253 : : * When we pull up a subquery, any AppendRelInfo references to the subquery's
4254 : : * RT index have to be replaced by the substituted relid (and there had better
4255 : : * be only one). We also need to apply substitute_phv_relids to their
4256 : : * translated_vars lists, since those might contain PlaceHolderVars.
4257 : : *
4258 : : * We assume we may modify the AppendRelInfo nodes in-place.
4259 : : */
4260 : : static void
1091 4261 : 4300 : fix_append_rel_relids(PlannerInfo *root, int varno, Relids subrelids)
4262 : : {
4263 : : ListCell *l;
7257 4264 : 4300 : int subvarno = -1;
4265 : :
4266 : : /*
4267 : : * We only want to extract the member relid once, but we mustn't fail
4268 : : * immediately if there are multiple members; it could be that none of the
4269 : : * AppendRelInfo nodes refer to it. So compute it on first use. Note that
4270 : : * bms_singleton_member will complain if set is not singleton.
4271 : : */
1091 4272 [ + + + + : 10194 : foreach(l, root->append_rel_list)
+ + ]
4273 : : {
7257 4274 : 5894 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
4275 : :
4276 : : /* The parent_relid shouldn't ever be a pullup target */
4277 [ - + ]: 5894 : Assert(appinfo->parent_relid != varno);
4278 : :
4279 [ + + ]: 5894 : if (appinfo->child_relid == varno)
4280 : : {
4281 [ + - ]: 3190 : if (subvarno < 0)
4282 : 3190 : subvarno = bms_singleton_member(subrelids);
4283 : 3190 : appinfo->child_relid = subvarno;
4284 : : }
4285 : :
4286 : : /* Also fix up any PHVs in its translated vars */
1091 4287 [ + + ]: 5894 : if (root->glob->lastPHId != 0)
4288 : 81 : substitute_phv_relids((Node *) appinfo->translated_vars,
4289 : : varno, subrelids);
4290 : : }
7257 4291 : 4300 : }
4292 : :
4293 : : /*
4294 : : * get_relids_in_jointree: get set of RT indexes present in a jointree
4295 : : *
4296 : : * Base-relation relids are always included in the result.
4297 : : * If include_outer_joins is true, outer-join RT indexes are included.
4298 : : * If include_inner_joins is true, inner-join RT indexes are included.
4299 : : *
4300 : : * Note that for most purposes in the planner, outer joins are included
4301 : : * in standard relid sets. Setting include_inner_joins true is only
4302 : : * appropriate for special purposes during subquery flattening.
4303 : : */
4304 : : Relids
1052 4305 : 53283 : get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
4306 : : bool include_inner_joins)
4307 : : {
8348 4308 : 53283 : Relids result = NULL;
4309 : :
8367 4310 [ - + ]: 53283 : if (jtnode == NULL)
8367 tgl@sss.pgh.pa.us 4311 :UBC 0 : return result;
8367 tgl@sss.pgh.pa.us 4312 [ + + ]:CBC 53283 : if (IsA(jtnode, RangeTblRef))
4313 : : {
4314 : 26846 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4315 : :
8348 4316 : 26846 : result = bms_make_singleton(varno);
4317 : : }
8367 4318 [ + + ]: 26437 : else if (IsA(jtnode, FromExpr))
4319 : : {
4320 : 23248 : FromExpr *f = (FromExpr *) jtnode;
4321 : : ListCell *l;
4322 : :
4323 [ + - + + : 47132 : foreach(l, f->fromlist)
+ + ]
4324 : : {
8348 4325 : 23884 : result = bms_join(result,
6331 4326 : 23884 : get_relids_in_jointree(lfirst(l),
4327 : : include_outer_joins,
4328 : : include_inner_joins));
4329 : : }
4330 : : }
8367 4331 [ + - ]: 3189 : else if (IsA(jtnode, JoinExpr))
4332 : : {
4333 : 3189 : JoinExpr *j = (JoinExpr *) jtnode;
4334 : :
1052 4335 : 3189 : result = get_relids_in_jointree(j->larg,
4336 : : include_outer_joins,
4337 : : include_inner_joins);
6331 4338 : 3189 : result = bms_join(result,
4339 : : get_relids_in_jointree(j->rarg,
4340 : : include_outer_joins,
4341 : : include_inner_joins));
1052 4342 [ + + ]: 3189 : if (j->rtindex)
4343 : : {
4344 [ + + ]: 3026 : if (j->jointype == JOIN_INNER)
4345 : : {
4346 [ + + ]: 1355 : if (include_inner_joins)
4347 : 537 : result = bms_add_member(result, j->rtindex);
4348 : : }
4349 : : else
4350 : : {
4351 [ + + ]: 1671 : if (include_outer_joins)
4352 : 1089 : result = bms_add_member(result, j->rtindex);
4353 : : }
4354 : : }
4355 : : }
4356 : : else
8181 tgl@sss.pgh.pa.us 4357 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
4358 : : (int) nodeTag(jtnode));
8367 tgl@sss.pgh.pa.us 4359 :CBC 53283 : return result;
4360 : : }
4361 : :
4362 : : /*
4363 : : * get_relids_for_join: get set of base+OJ RT indexes making up a join
4364 : : */
4365 : : Relids
2514 4366 : 179 : get_relids_for_join(Query *query, int joinrelid)
4367 : : {
4368 : : Node *jtnode;
4369 : :
4370 : 179 : jtnode = find_jointree_node_for_rel((Node *) query->jointree,
4371 : : joinrelid);
8367 4372 [ - + ]: 179 : if (!jtnode)
8181 tgl@sss.pgh.pa.us 4373 [ # # ]:UBC 0 : elog(ERROR, "could not find join node %d", joinrelid);
1052 tgl@sss.pgh.pa.us 4374 :CBC 179 : return get_relids_in_jointree(jtnode, true, false);
4375 : : }
4376 : :
4377 : : /*
4378 : : * find_jointree_node_for_rel: locate jointree node for a base or join RT index
4379 : : *
4380 : : * Returns NULL if not found
4381 : : */
4382 : : static Node *
8367 4383 : 865 : find_jointree_node_for_rel(Node *jtnode, int relid)
4384 : : {
4385 [ - + ]: 865 : if (jtnode == NULL)
8367 tgl@sss.pgh.pa.us 4386 :UBC 0 : return NULL;
8367 tgl@sss.pgh.pa.us 4387 [ + + ]:CBC 865 : if (IsA(jtnode, RangeTblRef))
4388 : : {
4389 : 227 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4390 : :
4391 [ - + ]: 227 : if (relid == varno)
8367 tgl@sss.pgh.pa.us 4392 :UBC 0 : return jtnode;
4393 : : }
8367 tgl@sss.pgh.pa.us 4394 [ + + ]:CBC 638 : else if (IsA(jtnode, FromExpr))
4395 : : {
4396 : 184 : FromExpr *f = (FromExpr *) jtnode;
4397 : : ListCell *l;
4398 : :
4399 [ + - + - : 193 : foreach(l, f->fromlist)
+ - ]
4400 : : {
4401 : 193 : jtnode = find_jointree_node_for_rel(lfirst(l), relid);
4402 [ + + ]: 193 : if (jtnode)
4403 : 184 : return jtnode;
4404 : : }
4405 : : }
4406 [ + - ]: 454 : else if (IsA(jtnode, JoinExpr))
4407 : : {
4408 : 454 : JoinExpr *j = (JoinExpr *) jtnode;
4409 : :
4410 [ + + ]: 454 : if (relid == j->rtindex)
4411 : 179 : return jtnode;
4412 : 275 : jtnode = find_jointree_node_for_rel(j->larg, relid);
4413 [ + + ]: 275 : if (jtnode)
4414 : 57 : return jtnode;
4415 : 218 : jtnode = find_jointree_node_for_rel(j->rarg, relid);
4416 [ + - ]: 218 : if (jtnode)
4417 : 218 : return jtnode;
4418 : : }
4419 : : else
8181 tgl@sss.pgh.pa.us 4420 [ # # ]:UBC 0 : elog(ERROR, "unrecognized node type: %d",
4421 : : (int) nodeTag(jtnode));
8367 tgl@sss.pgh.pa.us 4422 :CBC 227 : return NULL;
4423 : : }
4424 : :
4425 : : /*
4426 : : * get_nullingrels: collect info about which outer joins null which relations
4427 : : *
4428 : : * The result struct contains, for each leaf relation used in the query,
4429 : : * the set of relids of outer joins that potentially null that rel.
4430 : : */
4431 : : static nullingrel_info *
382 4432 : 583 : get_nullingrels(Query *parse)
4433 : : {
4434 : 583 : nullingrel_info *result = palloc_object(nullingrel_info);
4435 : :
4436 : 583 : result->rtlength = list_length(parse->rtable);
4437 : 583 : result->nullingrels = palloc0_array(Relids, result->rtlength + 1);
4438 : 583 : get_nullingrels_recurse((Node *) parse->jointree, NULL, result);
4439 : 583 : return result;
4440 : : }
4441 : :
4442 : : /*
4443 : : * Recursive guts of get_nullingrels().
4444 : : *
4445 : : * Note: at any recursion level, the passed-down upper_nullingrels must be
4446 : : * treated as a constant, but it can be stored directly into *info
4447 : : * if we're at leaf level. Upper recursion levels do not free their mutated
4448 : : * copies of the nullingrels, because those are probably referenced by
4449 : : * at least one leaf rel.
4450 : : */
4451 : : static void
4452 : 3096 : get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
4453 : : nullingrel_info *info)
4454 : : {
4455 [ - + ]: 3096 : if (jtnode == NULL)
382 tgl@sss.pgh.pa.us 4456 :UBC 0 : return;
382 tgl@sss.pgh.pa.us 4457 [ + + ]:CBC 3096 : if (IsA(jtnode, RangeTblRef))
4458 : : {
4459 : 1637 : int varno = ((RangeTblRef *) jtnode)->rtindex;
4460 : :
4461 [ + - - + ]: 1637 : Assert(varno > 0 && varno <= info->rtlength);
4462 : 1637 : info->nullingrels[varno] = upper_nullingrels;
4463 : : }
4464 [ + + ]: 1459 : else if (IsA(jtnode, FromExpr))
4465 : : {
4466 : 625 : FromExpr *f = (FromExpr *) jtnode;
4467 : : ListCell *l;
4468 : :
4469 [ + - + + : 1470 : foreach(l, f->fromlist)
+ + ]
4470 : : {
4471 : 845 : get_nullingrels_recurse(lfirst(l), upper_nullingrels, info);
4472 : : }
4473 : : }
4474 [ + - ]: 834 : else if (IsA(jtnode, JoinExpr))
4475 : : {
4476 : 834 : JoinExpr *j = (JoinExpr *) jtnode;
4477 : : Relids local_nullingrels;
4478 : :
4479 [ + + + - : 834 : switch (j->jointype)
- ]
4480 : : {
4481 : 303 : case JOIN_INNER:
4482 : 303 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4483 : 303 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4484 : 303 : break;
4485 : 528 : case JOIN_LEFT:
4486 : : case JOIN_SEMI:
4487 : : case JOIN_ANTI:
4488 : 528 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4489 : : j->rtindex);
4490 : 528 : get_nullingrels_recurse(j->larg, upper_nullingrels, info);
4491 : 528 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4492 : 528 : break;
4493 : 3 : case JOIN_FULL:
4494 : 3 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4495 : : j->rtindex);
4496 : 3 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4497 : 3 : get_nullingrels_recurse(j->rarg, local_nullingrels, info);
4498 : 3 : break;
382 tgl@sss.pgh.pa.us 4499 :UBC 0 : case JOIN_RIGHT:
4500 : 0 : local_nullingrels = bms_add_member(bms_copy(upper_nullingrels),
4501 : : j->rtindex);
4502 : 0 : get_nullingrels_recurse(j->larg, local_nullingrels, info);
4503 : 0 : get_nullingrels_recurse(j->rarg, upper_nullingrels, info);
4504 : 0 : break;
4505 : 0 : default:
4506 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
4507 : : (int) j->jointype);
4508 : : break;
4509 : : }
4510 : : }
4511 : : else
4512 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d",
4513 : : (int) nodeTag(jtnode));
4514 : : }
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