Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * nodeMemoize.c
4 : : * Routines to handle caching of results from parameterized nodes
5 : : *
6 : : * Portions Copyright (c) 2021-2025, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : *
10 : : * IDENTIFICATION
11 : : * src/backend/executor/nodeMemoize.c
12 : : *
13 : : * Memoize nodes are intended to sit above parameterized nodes in the plan
14 : : * tree in order to cache results from them. The intention here is that a
15 : : * repeat scan with a parameter value that has already been seen by the node
16 : : * can fetch tuples from the cache rather than having to re-scan the inner
17 : : * node all over again. The query planner may choose to make use of one of
18 : : * these when it thinks rescans for previously seen values are likely enough
19 : : * to warrant adding the additional node.
20 : : *
21 : : * The method of cache we use is a hash table. When the cache fills, we never
22 : : * spill tuples to disk, instead, we choose to evict the least recently used
23 : : * cache entry from the cache. We remember the least recently used entry by
24 : : * always pushing new entries and entries we look for onto the tail of a
25 : : * doubly linked list. This means that older items always bubble to the top
26 : : * of this LRU list.
27 : : *
28 : : * Sometimes our callers won't run their scans to completion. For example a
29 : : * semi-join only needs to run until it finds a matching tuple, and once it
30 : : * does, the join operator skips to the next outer tuple and does not execute
31 : : * the inner side again on that scan. Because of this, we must keep track of
32 : : * when a cache entry is complete, and by default, we know it is when we run
33 : : * out of tuples to read during the scan. However, there are cases where we
34 : : * can mark the cache entry as complete without exhausting the scan of all
35 : : * tuples. One case is unique joins, where the join operator knows that there
36 : : * will only be at most one match for any given outer tuple. In order to
37 : : * support such cases we allow the "singlerow" option to be set for the cache.
38 : : * This option marks the cache entry as complete after we read the first tuple
39 : : * from the subnode.
40 : : *
41 : : * It's possible when we're filling the cache for a given set of parameters
42 : : * that we're unable to free enough memory to store any more tuples. If this
43 : : * happens then we'll have already evicted all other cache entries. When
44 : : * caching another tuple would cause us to exceed our memory budget, we must
45 : : * free the entry that we're currently populating and move the state machine
46 : : * into MEMO_CACHE_BYPASS_MODE. This means that we'll not attempt to cache
47 : : * any further tuples for this particular scan. We don't have the memory for
48 : : * it. The state machine will be reset again on the next rescan. If the
49 : : * memory requirements to cache the next parameter's tuples are less
50 : : * demanding, then that may allow us to start putting useful entries back into
51 : : * the cache again.
52 : : *
53 : : *
54 : : * INTERFACE ROUTINES
55 : : * ExecMemoize - lookup cache, exec subplan when not found
56 : : * ExecInitMemoize - initialize node and subnodes
57 : : * ExecEndMemoize - shutdown node and subnodes
58 : : * ExecReScanMemoize - rescan the memoize node
59 : : *
60 : : * ExecMemoizeEstimate estimates DSM space needed for parallel plan
61 : : * ExecMemoizeInitializeDSM initialize DSM for parallel plan
62 : : * ExecMemoizeInitializeWorker attach to DSM info in parallel worker
63 : : * ExecMemoizeRetrieveInstrumentation get instrumentation from worker
64 : : *-------------------------------------------------------------------------
65 : : */
66 : :
67 : : #include "postgres.h"
68 : :
69 : : #include "common/hashfn.h"
70 : : #include "executor/executor.h"
71 : : #include "executor/nodeMemoize.h"
72 : : #include "lib/ilist.h"
73 : : #include "miscadmin.h"
74 : : #include "utils/datum.h"
75 : : #include "utils/lsyscache.h"
76 : :
77 : : /* States of the ExecMemoize state machine */
78 : : #define MEMO_CACHE_LOOKUP 1 /* Attempt to perform a cache lookup */
79 : : #define MEMO_CACHE_FETCH_NEXT_TUPLE 2 /* Get another tuple from the cache */
80 : : #define MEMO_FILLING_CACHE 3 /* Read outer node to fill cache */
81 : : #define MEMO_CACHE_BYPASS_MODE 4 /* Bypass mode. Just read from our
82 : : * subplan without caching anything */
83 : : #define MEMO_END_OF_SCAN 5 /* Ready for rescan */
84 : :
85 : :
86 : : /* Helper macros for memory accounting */
87 : : #define EMPTY_ENTRY_MEMORY_BYTES(e) (sizeof(MemoizeEntry) + \
88 : : sizeof(MemoizeKey) + \
89 : : (e)->key->params->t_len);
90 : : #define CACHE_TUPLE_BYTES(t) (sizeof(MemoizeTuple) + \
91 : : (t)->mintuple->t_len)
92 : :
93 : : /* MemoizeTuple Stores an individually cached tuple */
94 : : typedef struct MemoizeTuple
95 : : {
96 : : MinimalTuple mintuple; /* Cached tuple */
97 : : struct MemoizeTuple *next; /* The next tuple with the same parameter
98 : : * values or NULL if it's the last one */
99 : : } MemoizeTuple;
100 : :
101 : : /*
102 : : * MemoizeKey
103 : : * The hash table key for cached entries plus the LRU list link
104 : : */
105 : : typedef struct MemoizeKey
106 : : {
107 : : MinimalTuple params;
108 : : dlist_node lru_node; /* Pointer to next/prev key in LRU list */
109 : : } MemoizeKey;
110 : :
111 : : /*
112 : : * MemoizeEntry
113 : : * The data struct that the cache hash table stores
114 : : */
115 : : typedef struct MemoizeEntry
116 : : {
117 : : MemoizeKey *key; /* Hash key for hash table lookups */
118 : : MemoizeTuple *tuplehead; /* Pointer to the first tuple or NULL if no
119 : : * tuples are cached for this entry */
120 : : uint32 hash; /* Hash value (cached) */
121 : : char status; /* Hash status */
122 : : bool complete; /* Did we read the outer plan to completion? */
123 : : } MemoizeEntry;
124 : :
125 : :
126 : : #define SH_PREFIX memoize
127 : : #define SH_ELEMENT_TYPE MemoizeEntry
128 : : #define SH_KEY_TYPE MemoizeKey *
129 : : #define SH_SCOPE static inline
130 : : #define SH_DECLARE
131 : : #include "lib/simplehash.h"
132 : :
133 : : static uint32 MemoizeHash_hash(struct memoize_hash *tb,
134 : : const MemoizeKey *key);
135 : : static bool MemoizeHash_equal(struct memoize_hash *tb,
136 : : const MemoizeKey *key1,
137 : : const MemoizeKey *key2);
138 : :
139 : : #define SH_PREFIX memoize
140 : : #define SH_ELEMENT_TYPE MemoizeEntry
141 : : #define SH_KEY_TYPE MemoizeKey *
142 : : #define SH_KEY key
143 : : #define SH_HASH_KEY(tb, key) MemoizeHash_hash(tb, key)
144 : : #define SH_EQUAL(tb, a, b) MemoizeHash_equal(tb, a, b)
145 : : #define SH_SCOPE static inline
146 : : #define SH_STORE_HASH
147 : : #define SH_GET_HASH(tb, a) a->hash
148 : : #define SH_DEFINE
149 : : #include "lib/simplehash.h"
150 : :
151 : : /*
152 : : * MemoizeHash_hash
153 : : * Hash function for simplehash hashtable. 'key' is unused here as we
154 : : * require that all table lookups first populate the MemoizeState's
155 : : * probeslot with the key values to be looked up.
156 : : */
157 : : static uint32
1515 drowley@postgresql.o 158 :CBC 355412 : MemoizeHash_hash(struct memoize_hash *tb, const MemoizeKey *key)
159 : : {
160 : 355412 : MemoizeState *mstate = (MemoizeState *) tb->private_data;
702 161 : 355412 : ExprContext *econtext = mstate->ss.ps.ps_ExprContext;
162 : : MemoryContext oldcontext;
1515 163 : 355412 : TupleTableSlot *pslot = mstate->probeslot;
1618 164 : 355412 : uint32 hashkey = 0;
1515 165 : 355412 : int numkeys = mstate->nkeys;
166 : :
702 167 : 355412 : oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
168 : :
1382 169 [ + + ]: 355412 : if (mstate->binary_mode)
170 : : {
171 [ + + ]: 111767 : for (int i = 0; i < numkeys; i++)
172 : : {
173 : : /* combine successive hashkeys by rotating */
1294 john.naylor@postgres 174 : 60350 : hashkey = pg_rotate_left32(hashkey, 1);
175 : :
1382 drowley@postgresql.o 176 [ + - ]: 60350 : if (!pslot->tts_isnull[i]) /* treat nulls as having hash key 0 */
177 : : {
178 : : CompactAttribute *attr;
179 : : uint32 hkey;
180 : :
260 181 : 60350 : attr = TupleDescCompactAttr(pslot->tts_tupleDescriptor, i);
182 : :
1382 183 : 60350 : hkey = datum_image_hash(pslot->tts_values[i], attr->attbyval, attr->attlen);
184 : :
185 : 60350 : hashkey ^= hkey;
186 : : }
187 : : }
188 : : }
189 : : else
190 : : {
191 : 303995 : FmgrInfo *hashfunctions = mstate->hashfunctions;
192 : 303995 : Oid *collations = mstate->collations;
193 : :
194 [ + + ]: 608489 : for (int i = 0; i < numkeys; i++)
195 : : {
196 : : /* combine successive hashkeys by rotating */
1294 john.naylor@postgres 197 : 304494 : hashkey = pg_rotate_left32(hashkey, 1);
198 : :
1382 drowley@postgresql.o 199 [ + + ]: 304494 : if (!pslot->tts_isnull[i]) /* treat nulls as having hash key 0 */
200 : : {
201 : : uint32 hkey;
202 : :
203 : 304054 : hkey = DatumGetUInt32(FunctionCall1Coll(&hashfunctions[i],
204 : 304054 : collations[i], pslot->tts_values[i]));
205 : 304054 : hashkey ^= hkey;
206 : : }
207 : : }
208 : : }
209 : :
702 210 : 355412 : MemoryContextSwitchTo(oldcontext);
1618 211 : 355412 : return murmurhash32(hashkey);
212 : : }
213 : :
214 : : /*
215 : : * MemoizeHash_equal
216 : : * Equality function for confirming hash value matches during a hash
217 : : * table lookup. 'key2' is never used. Instead the MemoizeState's
218 : : * probeslot is always populated with details of what's being looked up.
219 : : */
220 : : static bool
1515 221 : 307655 : MemoizeHash_equal(struct memoize_hash *tb, const MemoizeKey *key1,
222 : : const MemoizeKey *key2)
223 : : {
224 : 307655 : MemoizeState *mstate = (MemoizeState *) tb->private_data;
225 : 307655 : ExprContext *econtext = mstate->ss.ps.ps_ExprContext;
226 : 307655 : TupleTableSlot *tslot = mstate->tableslot;
227 : 307655 : TupleTableSlot *pslot = mstate->probeslot;
228 : :
229 : : /* probeslot should have already been prepared by prepare_probe_slot() */
1618 230 : 307655 : ExecStoreMinimalTuple(key1->params, tslot, false);
231 : :
1382 232 [ + + ]: 307655 : if (mstate->binary_mode)
233 : : {
234 : : MemoryContext oldcontext;
235 : 50993 : int numkeys = mstate->nkeys;
702 236 : 50993 : bool match = true;
237 : :
238 : 50993 : oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
239 : :
1382 240 : 50993 : slot_getallattrs(tslot);
241 : 50993 : slot_getallattrs(pslot);
242 : :
243 [ + + ]: 110751 : for (int i = 0; i < numkeys; i++)
244 : : {
245 : : CompactAttribute *attr;
246 : :
247 [ - + ]: 59758 : if (tslot->tts_isnull[i] != pslot->tts_isnull[i])
248 : : {
702 drowley@postgresql.o 249 :UBC 0 : match = false;
250 : 0 : break;
251 : : }
252 : :
253 : : /* both NULL? they're equal */
1382 drowley@postgresql.o 254 [ - + ]:CBC 59758 : if (tslot->tts_isnull[i])
1382 drowley@postgresql.o 255 :UBC 0 : continue;
256 : :
257 : : /* perform binary comparison on the two datums */
260 drowley@postgresql.o 258 :CBC 59758 : attr = TupleDescCompactAttr(tslot->tts_tupleDescriptor, i);
1382 259 [ - + ]: 59758 : if (!datum_image_eq(tslot->tts_values[i], pslot->tts_values[i],
260 : 59758 : attr->attbyval, attr->attlen))
261 : : {
702 drowley@postgresql.o 262 :UBC 0 : match = false;
263 : 0 : break;
264 : : }
265 : : }
266 : :
702 drowley@postgresql.o 267 :CBC 50993 : MemoryContextSwitchTo(oldcontext);
268 : 50993 : return match;
269 : : }
270 : : else
271 : : {
1382 272 : 256662 : econtext->ecxt_innertuple = tslot;
273 : 256662 : econtext->ecxt_outertuple = pslot;
544 274 : 256662 : return ExecQual(mstate->cache_eq_expr, econtext);
275 : : }
276 : : }
277 : :
278 : : /*
279 : : * Initialize the hash table to empty. The MemoizeState's hashtable field
280 : : * must point to NULL.
281 : : */
282 : : static void
1515 283 : 833 : build_hash_table(MemoizeState *mstate, uint32 size)
284 : : {
585 285 [ - + ]: 833 : Assert(mstate->hashtable == NULL);
286 : :
287 : : /* Make a guess at a good size when we're not given a valid size. */
1618 288 [ - + ]: 833 : if (size == 0)
1618 drowley@postgresql.o 289 :UBC 0 : size = 1024;
290 : :
291 : : /* memoize_create will convert the size to a power of 2 */
1515 drowley@postgresql.o 292 :CBC 833 : mstate->hashtable = memoize_create(mstate->tableContext, size, mstate);
1618 293 : 833 : }
294 : :
295 : : /*
296 : : * prepare_probe_slot
297 : : * Populate mstate's probeslot with the values from the tuple stored
298 : : * in 'key'. If 'key' is NULL, then perform the population by evaluating
299 : : * mstate's param_exprs.
300 : : */
301 : : static inline void
1515 302 : 355412 : prepare_probe_slot(MemoizeState *mstate, MemoizeKey *key)
303 : : {
304 : 355412 : TupleTableSlot *pslot = mstate->probeslot;
305 : 355412 : TupleTableSlot *tslot = mstate->tableslot;
306 : 355412 : int numKeys = mstate->nkeys;
307 : :
1618 308 : 355412 : ExecClearTuple(pslot);
309 : :
310 [ + + ]: 355412 : if (key == NULL)
311 : : {
901 312 : 354212 : ExprContext *econtext = mstate->ss.ps.ps_ExprContext;
313 : : MemoryContext oldcontext;
314 : :
315 : 354212 : oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
316 : :
317 : : /* Set the probeslot's values based on the current parameter values */
1618 318 [ + + ]: 717856 : for (int i = 0; i < numKeys; i++)
1515 319 : 363644 : pslot->tts_values[i] = ExecEvalExpr(mstate->param_exprs[i],
320 : : econtext,
1618 321 : 363644 : &pslot->tts_isnull[i]);
322 : :
901 323 : 354212 : MemoryContextSwitchTo(oldcontext);
324 : : }
325 : : else
326 : : {
327 : : /* Process the key's MinimalTuple and store the values in probeslot */
1618 328 : 1200 : ExecStoreMinimalTuple(key->params, tslot, false);
329 : 1200 : slot_getallattrs(tslot);
330 : 1200 : memcpy(pslot->tts_values, tslot->tts_values, sizeof(Datum) * numKeys);
331 : 1200 : memcpy(pslot->tts_isnull, tslot->tts_isnull, sizeof(bool) * numKeys);
332 : : }
333 : :
334 : 355412 : ExecStoreVirtualTuple(pslot);
335 : 355412 : }
336 : :
337 : : /*
338 : : * entry_purge_tuples
339 : : * Remove all tuples from the cache entry pointed to by 'entry'. This
340 : : * leaves an empty cache entry. Also, update the memory accounting to
341 : : * reflect the removal of the tuples.
342 : : */
343 : : static inline void
1515 344 : 1194 : entry_purge_tuples(MemoizeState *mstate, MemoizeEntry *entry)
345 : : {
346 : 1194 : MemoizeTuple *tuple = entry->tuplehead;
1618 347 : 1194 : uint64 freed_mem = 0;
348 : :
349 [ + + ]: 2388 : while (tuple != NULL)
350 : : {
1515 351 : 1194 : MemoizeTuple *next = tuple->next;
352 : :
1618 353 : 1194 : freed_mem += CACHE_TUPLE_BYTES(tuple);
354 : :
355 : : /* Free memory used for this tuple */
356 : 1194 : pfree(tuple->mintuple);
357 : 1194 : pfree(tuple);
358 : :
359 : 1194 : tuple = next;
360 : : }
361 : :
362 : 1194 : entry->complete = false;
363 : 1194 : entry->tuplehead = NULL;
364 : :
365 : : /* Update the memory accounting */
1515 366 : 1194 : mstate->mem_used -= freed_mem;
1618 367 : 1194 : }
368 : :
369 : : /*
370 : : * remove_cache_entry
371 : : * Remove 'entry' from the cache and free memory used by it.
372 : : */
373 : : static void
1515 374 : 1194 : remove_cache_entry(MemoizeState *mstate, MemoizeEntry *entry)
375 : : {
376 : 1194 : MemoizeKey *key = entry->key;
377 : :
1618 378 : 1194 : dlist_delete(&entry->key->lru_node);
379 : :
380 : : /* Remove all of the tuples from this entry */
1515 381 : 1194 : entry_purge_tuples(mstate, entry);
382 : :
383 : : /*
384 : : * Update memory accounting. entry_purge_tuples should have already
385 : : * subtracted the memory used for each cached tuple. Here we just update
386 : : * the amount used by the entry itself.
387 : : */
388 : 1194 : mstate->mem_used -= EMPTY_ENTRY_MEMORY_BYTES(entry);
389 : :
390 : : /* Remove the entry from the cache */
391 : 1194 : memoize_delete_item(mstate->hashtable, entry);
392 : :
1618 393 : 1194 : pfree(key->params);
394 : 1194 : pfree(key);
395 : 1194 : }
396 : :
397 : : /*
398 : : * cache_purge_all
399 : : * Remove all items from the cache
400 : : */
401 : : static void
1382 402 : 9 : cache_purge_all(MemoizeState *mstate)
403 : : {
585 404 : 9 : uint64 evictions = 0;
405 : :
406 [ + + ]: 9 : if (mstate->hashtable != NULL)
407 : 6 : evictions = mstate->hashtable->members;
408 : :
409 : : /*
410 : : * Likely the most efficient way to remove all items is to just reset the
411 : : * memory context for the cache and then rebuild a fresh hash table. This
412 : : * saves having to remove each item one by one and pfree each cached tuple
413 : : */
1382 414 : 9 : MemoryContextReset(mstate->tableContext);
415 : :
416 : : /* NULLify so we recreate the table on the next call */
585 417 : 9 : mstate->hashtable = NULL;
418 : :
419 : : /* reset the LRU list */
1382 420 : 9 : dlist_init(&mstate->lru_list);
421 : 9 : mstate->last_tuple = NULL;
422 : 9 : mstate->entry = NULL;
423 : :
424 : 9 : mstate->mem_used = 0;
425 : :
426 : : /* XXX should we add something new to track these purges? */
427 : 9 : mstate->stats.cache_evictions += evictions; /* Update Stats */
428 : 9 : }
429 : :
430 : : /*
431 : : * cache_reduce_memory
432 : : * Evict older and less recently used items from the cache in order to
433 : : * reduce the memory consumption back to something below the
434 : : * MemoizeState's mem_limit.
435 : : *
436 : : * 'specialkey', if not NULL, causes the function to return false if the entry
437 : : * which the key belongs to is removed from the cache.
438 : : */
439 : : static bool
1515 440 : 1194 : cache_reduce_memory(MemoizeState *mstate, MemoizeKey *specialkey)
441 : : {
1618 442 : 1194 : bool specialkey_intact = true; /* for now */
443 : : dlist_mutable_iter iter;
444 : 1194 : uint64 evictions = 0;
445 : :
446 : : /* Update peak memory usage */
1515 447 [ + + ]: 1194 : if (mstate->mem_used > mstate->stats.mem_peak)
448 : 3 : mstate->stats.mem_peak = mstate->mem_used;
449 : :
450 : : /* We expect only to be called when we've gone over budget on memory */
451 [ - + ]: 1194 : Assert(mstate->mem_used > mstate->mem_limit);
452 : :
453 : : /* Start the eviction process starting at the head of the LRU list. */
454 [ + - + - ]: 1194 : dlist_foreach_modify(iter, &mstate->lru_list)
455 : : {
456 : 1194 : MemoizeKey *key = dlist_container(MemoizeKey, lru_node, iter.cur);
457 : : MemoizeEntry *entry;
458 : :
459 : : /*
460 : : * Populate the hash probe slot in preparation for looking up this LRU
461 : : * entry.
462 : : */
463 : 1194 : prepare_probe_slot(mstate, key);
464 : :
465 : : /*
466 : : * Ideally the LRU list pointers would be stored in the entry itself
467 : : * rather than in the key. Unfortunately, we can't do that as the
468 : : * simplehash.h code may resize the table and allocate new memory for
469 : : * entries which would result in those pointers pointing to the old
470 : : * buckets. However, it's fine to use the key to store this as that's
471 : : * only referenced by a pointer in the entry, which of course follows
472 : : * the entry whenever the hash table is resized. Since we only have a
473 : : * pointer to the key here, we must perform a hash table lookup to
474 : : * find the entry that the key belongs to.
475 : : */
476 : 1194 : entry = memoize_lookup(mstate->hashtable, NULL);
477 : :
478 : : /*
479 : : * Sanity check that we found the entry belonging to the LRU list
480 : : * item. A misbehaving hash or equality function could cause the
481 : : * entry not to be found or the wrong entry to be found.
482 : : */
1186 483 [ + - - + : 1194 : if (unlikely(entry == NULL || entry->key != key))
- + ]
1186 drowley@postgresql.o 484 [ # # ]:UBC 0 : elog(ERROR, "could not find memoization table entry");
485 : :
486 : : /*
487 : : * If we're being called to free memory while the cache is being
488 : : * populated with new tuples, then we'd better take some care as we
489 : : * could end up freeing the entry which 'specialkey' belongs to.
490 : : * Generally callers will pass 'specialkey' as the key for the cache
491 : : * entry which is currently being populated, so we must set
492 : : * 'specialkey_intact' to false to inform the caller the specialkey
493 : : * entry has been removed.
494 : : */
1618 drowley@postgresql.o 495 [ - + ]:CBC 1194 : if (key == specialkey)
1618 drowley@postgresql.o 496 :UBC 0 : specialkey_intact = false;
497 : :
498 : : /*
499 : : * Finally remove the entry. This will remove from the LRU list too.
500 : : */
1515 drowley@postgresql.o 501 :CBC 1194 : remove_cache_entry(mstate, entry);
502 : :
1618 503 : 1194 : evictions++;
504 : :
505 : : /* Exit if we've freed enough memory */
1515 506 [ + - ]: 1194 : if (mstate->mem_used <= mstate->mem_limit)
1618 507 : 1194 : break;
508 : : }
509 : :
1515 510 : 1194 : mstate->stats.cache_evictions += evictions; /* Update Stats */
511 : :
1618 512 : 1194 : return specialkey_intact;
513 : : }
514 : :
515 : : /*
516 : : * cache_lookup
517 : : * Perform a lookup to see if we've already cached tuples based on the
518 : : * scan's current parameters. If we find an existing entry we move it to
519 : : * the end of the LRU list, set *found to true then return it. If we
520 : : * don't find an entry then we create a new one and add it to the end of
521 : : * the LRU list. We also update cache memory accounting and remove older
522 : : * entries if we go over the memory budget. If we managed to free enough
523 : : * memory we return the new entry, else we return NULL.
524 : : *
525 : : * Callers can assume we'll never return NULL when *found is true.
526 : : */
527 : : static MemoizeEntry *
1515 528 : 354212 : cache_lookup(MemoizeState *mstate, bool *found)
529 : : {
530 : : MemoizeKey *key;
531 : : MemoizeEntry *entry;
532 : : MemoryContext oldcontext;
533 : :
534 : : /* prepare the probe slot with the current scan parameters */
535 : 354212 : prepare_probe_slot(mstate, NULL);
536 : :
537 : : /*
538 : : * Add the new entry to the cache. No need to pass a valid key since the
539 : : * hash function uses mstate's probeslot, which we populated above.
540 : : */
541 : 354212 : entry = memoize_insert(mstate->hashtable, NULL, found);
542 : :
1618 543 [ + + ]: 354212 : if (*found)
544 : : {
545 : : /*
546 : : * Move existing entry to the tail of the LRU list to mark it as the
547 : : * most recently used item.
548 : : */
1515 549 : 306455 : dlist_move_tail(&mstate->lru_list, &entry->key->lru_node);
550 : :
1618 551 : 306455 : return entry;
552 : : }
553 : :
1515 554 : 47757 : oldcontext = MemoryContextSwitchTo(mstate->tableContext);
555 : :
556 : : /* Allocate a new key */
557 : 47757 : entry->key = key = (MemoizeKey *) palloc(sizeof(MemoizeKey));
558 : 47757 : key->params = ExecCopySlotMinimalTuple(mstate->probeslot);
559 : :
560 : : /* Update the total cache memory utilization */
561 : 47757 : mstate->mem_used += EMPTY_ENTRY_MEMORY_BYTES(entry);
562 : :
563 : : /* Initialize this entry */
1618 564 : 47757 : entry->complete = false;
565 : 47757 : entry->tuplehead = NULL;
566 : :
567 : : /*
568 : : * Since this is the most recently used entry, push this entry onto the
569 : : * end of the LRU list.
570 : : */
1515 571 : 47757 : dlist_push_tail(&mstate->lru_list, &entry->key->lru_node);
572 : :
573 : 47757 : mstate->last_tuple = NULL;
574 : :
1618 575 : 47757 : MemoryContextSwitchTo(oldcontext);
576 : :
577 : : /*
578 : : * If we've gone over our memory budget, then we'll free up some space in
579 : : * the cache.
580 : : */
1515 581 [ + + ]: 47757 : if (mstate->mem_used > mstate->mem_limit)
582 : : {
583 : : /*
584 : : * Try to free up some memory. It's highly unlikely that we'll fail
585 : : * to do so here since the entry we've just added is yet to contain
586 : : * any tuples and we're able to remove any other entry to reduce the
587 : : * memory consumption.
588 : : */
589 [ - + ]: 1194 : if (unlikely(!cache_reduce_memory(mstate, key)))
1618 drowley@postgresql.o 590 :UBC 0 : return NULL;
591 : :
592 : : /*
593 : : * The process of removing entries from the cache may have caused the
594 : : * code in simplehash.h to shuffle elements to earlier buckets in the
595 : : * hash table. If it has, we'll need to find the entry again by
596 : : * performing a lookup. Fortunately, we can detect if this has
597 : : * happened by seeing if the entry is still in use and that the key
598 : : * pointer matches our expected key.
599 : : */
1515 drowley@postgresql.o 600 [ + - + + ]:CBC 1194 : if (entry->status != memoize_SH_IN_USE || entry->key != key)
601 : : {
602 : : /*
603 : : * We need to repopulate the probeslot as lookups performed during
604 : : * the cache evictions above will have stored some other key.
605 : : */
606 : 6 : prepare_probe_slot(mstate, key);
607 : :
608 : : /* Re-find the newly added entry */
609 : 6 : entry = memoize_lookup(mstate->hashtable, NULL);
1618 610 [ - + ]: 6 : Assert(entry != NULL);
611 : : }
612 : : }
613 : :
614 : 47757 : return entry;
615 : : }
616 : :
617 : : /*
618 : : * cache_store_tuple
619 : : * Add the tuple stored in 'slot' to the mstate's current cache entry.
620 : : * The cache entry must have already been made with cache_lookup().
621 : : * mstate's last_tuple field must point to the tail of mstate->entry's
622 : : * list of tuples.
623 : : */
624 : : static bool
1515 625 : 44837 : cache_store_tuple(MemoizeState *mstate, TupleTableSlot *slot)
626 : : {
627 : : MemoizeTuple *tuple;
628 : 44837 : MemoizeEntry *entry = mstate->entry;
629 : : MemoryContext oldcontext;
630 : :
1618 631 [ - + ]: 44837 : Assert(slot != NULL);
632 [ - + ]: 44837 : Assert(entry != NULL);
633 : :
1515 634 : 44837 : oldcontext = MemoryContextSwitchTo(mstate->tableContext);
635 : :
636 : 44837 : tuple = (MemoizeTuple *) palloc(sizeof(MemoizeTuple));
1618 637 : 44837 : tuple->mintuple = ExecCopySlotMinimalTuple(slot);
638 : 44837 : tuple->next = NULL;
639 : :
640 : : /* Account for the memory we just consumed */
1515 641 : 44837 : mstate->mem_used += CACHE_TUPLE_BYTES(tuple);
642 : :
1618 643 [ + + ]: 44837 : if (entry->tuplehead == NULL)
644 : : {
645 : : /*
646 : : * This is the first tuple for this entry, so just point the list head
647 : : * to it.
648 : : */
649 : 44608 : entry->tuplehead = tuple;
650 : : }
651 : : else
652 : : {
653 : : /* push this tuple onto the tail of the list */
1515 654 : 229 : mstate->last_tuple->next = tuple;
655 : : }
656 : :
657 : 44837 : mstate->last_tuple = tuple;
1618 658 : 44837 : MemoryContextSwitchTo(oldcontext);
659 : :
660 : : /*
661 : : * If we've gone over our memory budget then free up some space in the
662 : : * cache.
663 : : */
1515 664 [ - + ]: 44837 : if (mstate->mem_used > mstate->mem_limit)
665 : : {
1515 drowley@postgresql.o 666 :UBC 0 : MemoizeKey *key = entry->key;
667 : :
668 [ # # ]: 0 : if (!cache_reduce_memory(mstate, key))
1618 669 : 0 : return false;
670 : :
671 : : /*
672 : : * The process of removing entries from the cache may have caused the
673 : : * code in simplehash.h to shuffle elements to earlier buckets in the
674 : : * hash table. If it has, we'll need to find the entry again by
675 : : * performing a lookup. Fortunately, we can detect if this has
676 : : * happened by seeing if the entry is still in use and that the key
677 : : * pointer matches our expected key.
678 : : */
1515 679 [ # # # # ]: 0 : if (entry->status != memoize_SH_IN_USE || entry->key != key)
680 : : {
681 : : /*
682 : : * We need to repopulate the probeslot as lookups performed during
683 : : * the cache evictions above will have stored some other key.
684 : : */
685 : 0 : prepare_probe_slot(mstate, key);
686 : :
687 : : /* Re-find the entry */
688 : 0 : mstate->entry = entry = memoize_lookup(mstate->hashtable, NULL);
1618 689 [ # # ]: 0 : Assert(entry != NULL);
690 : : }
691 : : }
692 : :
1618 drowley@postgresql.o 693 :CBC 44837 : return true;
694 : : }
695 : :
696 : : static TupleTableSlot *
1515 697 : 433290 : ExecMemoize(PlanState *pstate)
698 : : {
699 : 433290 : MemoizeState *node = castNode(MemoizeState, pstate);
544 700 : 433290 : ExprContext *econtext = node->ss.ps.ps_ExprContext;
701 : : PlanState *outerNode;
702 : : TupleTableSlot *slot;
703 : :
704 [ - + ]: 433290 : CHECK_FOR_INTERRUPTS();
705 : :
706 : : /*
707 : : * Reset per-tuple memory context to free any expression evaluation
708 : : * storage allocated in the previous tuple cycle.
709 : : */
710 : 433290 : ResetExprContext(econtext);
711 : :
1515 712 [ + + + - : 433290 : switch (node->mstatus)
- - ]
713 : : {
714 : 354212 : case MEMO_CACHE_LOOKUP:
715 : : {
716 : : MemoizeEntry *entry;
717 : : TupleTableSlot *outerslot;
718 : : bool found;
719 : :
1618 720 [ - + ]: 354212 : Assert(node->entry == NULL);
721 : :
722 : : /* first call? we'll need a hash table. */
585 723 [ + + ]: 354212 : if (unlikely(node->hashtable == NULL))
724 : 833 : build_hash_table(node, ((Memoize *) pstate->plan)->est_entries);
725 : :
726 : : /*
727 : : * We're only ever in this state for the first call of the
728 : : * scan. Here we have a look to see if we've already seen the
729 : : * current parameters before and if we have already cached a
730 : : * complete set of records that the outer plan will return for
731 : : * these parameters.
732 : : *
733 : : * When we find a valid cache entry, we'll return the first
734 : : * tuple from it. If not found, we'll create a cache entry and
735 : : * then try to fetch a tuple from the outer scan. If we find
736 : : * one there, we'll try to cache it.
737 : : */
738 : :
739 : : /* see if we've got anything cached for the current parameters */
1618 740 : 354212 : entry = cache_lookup(node, &found);
741 : :
742 [ + + + - ]: 354212 : if (found && entry->complete)
743 : : {
744 : 306455 : node->stats.cache_hits += 1; /* stats update */
745 : :
746 : : /*
747 : : * Set last_tuple and entry so that the state
748 : : * MEMO_CACHE_FETCH_NEXT_TUPLE can easily find the next
749 : : * tuple for these parameters.
750 : : */
751 : 306455 : node->last_tuple = entry->tuplehead;
752 : 306455 : node->entry = entry;
753 : :
754 : : /* Fetch the first cached tuple, if there is one */
755 [ + + ]: 306455 : if (entry->tuplehead)
756 : : {
1515 757 : 163090 : node->mstatus = MEMO_CACHE_FETCH_NEXT_TUPLE;
758 : :
1618 759 : 163090 : slot = node->ss.ps.ps_ResultTupleSlot;
760 : 163090 : ExecStoreMinimalTuple(entry->tuplehead->mintuple,
761 : : slot, false);
762 : :
763 : 163090 : return slot;
764 : : }
765 : :
766 : : /* The cache entry is void of any tuples. */
1515 767 : 143365 : node->mstatus = MEMO_END_OF_SCAN;
1618 768 : 143365 : return NULL;
769 : : }
770 : :
771 : : /* Handle cache miss */
772 : 47757 : node->stats.cache_misses += 1; /* stats update */
773 : :
774 [ - + ]: 47757 : if (found)
775 : : {
776 : : /*
777 : : * A cache entry was found, but the scan for that entry
778 : : * did not run to completion. We'll just remove all
779 : : * tuples and start again. It might be tempting to
780 : : * continue where we left off, but there's no guarantee
781 : : * the outer node will produce the tuples in the same
782 : : * order as it did last time.
783 : : */
1618 drowley@postgresql.o 784 :UBC 0 : entry_purge_tuples(node, entry);
785 : : }
786 : :
787 : : /* Scan the outer node for a tuple to cache */
1618 drowley@postgresql.o 788 :CBC 47757 : outerNode = outerPlanState(node);
789 : 47757 : outerslot = ExecProcNode(outerNode);
790 [ + - + + ]: 47757 : if (TupIsNull(outerslot))
791 : : {
792 : : /*
793 : : * cache_lookup may have returned NULL due to failure to
794 : : * free enough cache space, so ensure we don't do anything
795 : : * here that assumes it worked. There's no need to go into
796 : : * bypass mode here as we're setting mstatus to end of
797 : : * scan.
798 : : */
799 [ + - ]: 3149 : if (likely(entry))
800 : 3149 : entry->complete = true;
801 : :
1515 802 : 3149 : node->mstatus = MEMO_END_OF_SCAN;
1618 803 : 3149 : return NULL;
804 : : }
805 : :
806 : 44608 : node->entry = entry;
807 : :
808 : : /*
809 : : * If we failed to create the entry or failed to store the
810 : : * tuple in the entry, then go into bypass mode.
811 : : */
812 [ + - - + : 44608 : if (unlikely(entry == NULL ||
- + ]
813 : : !cache_store_tuple(node, outerslot)))
814 : : {
1618 drowley@postgresql.o 815 :UBC 0 : node->stats.cache_overflows += 1; /* stats update */
816 : :
1515 817 : 0 : node->mstatus = MEMO_CACHE_BYPASS_MODE;
818 : :
819 : : /*
820 : : * No need to clear out last_tuple as we'll stay in bypass
821 : : * mode until the end of the scan.
822 : : */
823 : : }
824 : : else
825 : : {
826 : : /*
827 : : * If we only expect a single row from this scan then we
828 : : * can mark that we're not expecting more. This allows
829 : : * cache lookups to work even when the scan has not been
830 : : * executed to completion.
831 : : */
1618 drowley@postgresql.o 832 :CBC 44608 : entry->complete = node->singlerow;
1515 833 : 44608 : node->mstatus = MEMO_FILLING_CACHE;
834 : : }
835 : :
1618 836 : 44608 : slot = node->ss.ps.ps_ResultTupleSlot;
837 : 44608 : ExecCopySlot(slot, outerslot);
838 : 44608 : return slot;
839 : : }
840 : :
1515 841 : 45098 : case MEMO_CACHE_FETCH_NEXT_TUPLE:
842 : : {
843 : : /* We shouldn't be in this state if these are not set */
1618 844 [ - + ]: 45098 : Assert(node->entry != NULL);
845 [ - + ]: 45098 : Assert(node->last_tuple != NULL);
846 : :
847 : : /* Skip to the next tuple to output */
848 : 45098 : node->last_tuple = node->last_tuple->next;
849 : :
850 : : /* No more tuples in the cache */
851 [ + + ]: 45098 : if (node->last_tuple == NULL)
852 : : {
1515 853 : 42500 : node->mstatus = MEMO_END_OF_SCAN;
1618 854 : 42500 : return NULL;
855 : : }
856 : :
857 : 2598 : slot = node->ss.ps.ps_ResultTupleSlot;
858 : 2598 : ExecStoreMinimalTuple(node->last_tuple->mintuple, slot,
859 : : false);
860 : :
861 : 2598 : return slot;
862 : : }
863 : :
1515 864 : 33980 : case MEMO_FILLING_CACHE:
865 : : {
866 : : TupleTableSlot *outerslot;
867 : 33980 : MemoizeEntry *entry = node->entry;
868 : :
869 : : /* entry should already have been set by MEMO_CACHE_LOOKUP */
1618 870 [ - + ]: 33980 : Assert(entry != NULL);
871 : :
872 : : /*
873 : : * When in the MEMO_FILLING_CACHE state, we've just had a
874 : : * cache miss and are populating the cache with the current
875 : : * scan tuples.
876 : : */
877 : 33980 : outerNode = outerPlanState(node);
878 : 33980 : outerslot = ExecProcNode(outerNode);
879 [ + + + + ]: 33980 : if (TupIsNull(outerslot))
880 : : {
881 : : /* No more tuples. Mark it as complete */
882 : 33751 : entry->complete = true;
1515 883 : 33751 : node->mstatus = MEMO_END_OF_SCAN;
1618 884 : 33751 : return NULL;
885 : : }
886 : :
887 : : /*
888 : : * Validate if the planner properly set the singlerow flag. It
889 : : * should only set that if each cache entry can, at most,
890 : : * return 1 row.
891 : : */
892 [ - + ]: 229 : if (unlikely(entry->complete))
1618 drowley@postgresql.o 893 [ # # ]:UBC 0 : elog(ERROR, "cache entry already complete");
894 : :
895 : : /* Record the tuple in the current cache entry */
1618 drowley@postgresql.o 896 [ - + ]:CBC 229 : if (unlikely(!cache_store_tuple(node, outerslot)))
897 : : {
898 : : /* Couldn't store it? Handle overflow */
1618 drowley@postgresql.o 899 :UBC 0 : node->stats.cache_overflows += 1; /* stats update */
900 : :
1515 901 : 0 : node->mstatus = MEMO_CACHE_BYPASS_MODE;
902 : :
903 : : /*
904 : : * No need to clear out entry or last_tuple as we'll stay
905 : : * in bypass mode until the end of the scan.
906 : : */
907 : : }
908 : :
1618 drowley@postgresql.o 909 :CBC 229 : slot = node->ss.ps.ps_ResultTupleSlot;
910 : 229 : ExecCopySlot(slot, outerslot);
911 : 229 : return slot;
912 : : }
913 : :
1515 drowley@postgresql.o 914 :UBC 0 : case MEMO_CACHE_BYPASS_MODE:
915 : : {
916 : : TupleTableSlot *outerslot;
917 : :
918 : : /*
919 : : * When in bypass mode we just continue to read tuples without
920 : : * caching. We need to wait until the next rescan before we
921 : : * can come out of this mode.
922 : : */
1618 923 : 0 : outerNode = outerPlanState(node);
924 : 0 : outerslot = ExecProcNode(outerNode);
925 [ # # # # ]: 0 : if (TupIsNull(outerslot))
926 : : {
1515 927 : 0 : node->mstatus = MEMO_END_OF_SCAN;
1618 928 : 0 : return NULL;
929 : : }
930 : :
931 : 0 : slot = node->ss.ps.ps_ResultTupleSlot;
932 : 0 : ExecCopySlot(slot, outerslot);
933 : 0 : return slot;
934 : : }
935 : :
1515 936 : 0 : case MEMO_END_OF_SCAN:
937 : :
938 : : /*
939 : : * We've already returned NULL for this scan, but just in case
940 : : * something calls us again by mistake.
941 : : */
1618 942 : 0 : return NULL;
943 : :
944 : 0 : default:
1515 945 [ # # ]: 0 : elog(ERROR, "unrecognized memoize state: %d",
946 : : (int) node->mstatus);
947 : : return NULL;
948 : : } /* switch */
949 : : }
950 : :
951 : : MemoizeState *
1515 drowley@postgresql.o 952 :CBC 1020 : ExecInitMemoize(Memoize *node, EState *estate, int eflags)
953 : : {
954 : 1020 : MemoizeState *mstate = makeNode(MemoizeState);
955 : : Plan *outerNode;
956 : : int i;
957 : : int nkeys;
958 : : Oid *eqfuncoids;
959 : :
960 : : /* check for unsupported flags */
1618 961 [ - + ]: 1020 : Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
962 : :
1515 963 : 1020 : mstate->ss.ps.plan = (Plan *) node;
964 : 1020 : mstate->ss.ps.state = estate;
965 : 1020 : mstate->ss.ps.ExecProcNode = ExecMemoize;
966 : :
967 : : /*
968 : : * Miscellaneous initialization
969 : : *
970 : : * create expression context for node
971 : : */
972 : 1020 : ExecAssignExprContext(estate, &mstate->ss.ps);
973 : :
1618 974 : 1020 : outerNode = outerPlan(node);
1515 975 : 1020 : outerPlanState(mstate) = ExecInitNode(outerNode, estate, eflags);
976 : :
977 : : /*
978 : : * Initialize return slot and type. No need to initialize projection info
979 : : * because this node doesn't do projections.
980 : : */
981 : 1020 : ExecInitResultTupleSlotTL(&mstate->ss.ps, &TTSOpsMinimalTuple);
982 : 1020 : mstate->ss.ps.ps_ProjInfo = NULL;
983 : :
984 : : /*
985 : : * Initialize scan slot and type.
986 : : */
987 : 1020 : ExecCreateScanSlotFromOuterPlan(estate, &mstate->ss, &TTSOpsMinimalTuple);
988 : :
989 : : /*
990 : : * Set the state machine to lookup the cache. We won't find anything
991 : : * until we cache something, but this saves a special case to create the
992 : : * first entry.
993 : : */
994 : 1020 : mstate->mstatus = MEMO_CACHE_LOOKUP;
995 : :
996 : 1020 : mstate->nkeys = nkeys = node->numKeys;
997 : 1020 : mstate->hashkeydesc = ExecTypeFromExprList(node->param_exprs);
998 : 1020 : mstate->tableslot = MakeSingleTupleTableSlot(mstate->hashkeydesc,
999 : : &TTSOpsMinimalTuple);
1000 : 1020 : mstate->probeslot = MakeSingleTupleTableSlot(mstate->hashkeydesc,
1001 : : &TTSOpsVirtual);
1002 : :
1003 : 1020 : mstate->param_exprs = (ExprState **) palloc(nkeys * sizeof(ExprState *));
1004 : 1020 : mstate->collations = node->collations; /* Just point directly to the plan
1005 : : * data */
1006 : 1020 : mstate->hashfunctions = (FmgrInfo *) palloc(nkeys * sizeof(FmgrInfo));
1007 : :
1618 1008 : 1020 : eqfuncoids = palloc(nkeys * sizeof(Oid));
1009 : :
1010 [ + + ]: 2073 : for (i = 0; i < nkeys; i++)
1011 : : {
1012 : 1053 : Oid hashop = node->hashOperators[i];
1013 : : Oid left_hashfn;
1014 : : Oid right_hashfn;
1015 : 1053 : Expr *param_expr = (Expr *) list_nth(node->param_exprs, i);
1016 : :
1017 [ - + ]: 1053 : if (!get_op_hash_functions(hashop, &left_hashfn, &right_hashfn))
1618 drowley@postgresql.o 1018 [ # # ]:UBC 0 : elog(ERROR, "could not find hash function for hash operator %u",
1019 : : hashop);
1020 : :
1515 drowley@postgresql.o 1021 :CBC 1053 : fmgr_info(left_hashfn, &mstate->hashfunctions[i]);
1022 : :
1023 : 1053 : mstate->param_exprs[i] = ExecInitExpr(param_expr, (PlanState *) mstate);
1618 1024 : 1053 : eqfuncoids[i] = get_opcode(hashop);
1025 : : }
1026 : :
1515 1027 : 2040 : mstate->cache_eq_expr = ExecBuildParamSetEqual(mstate->hashkeydesc,
1028 : : &TTSOpsMinimalTuple,
1029 : : &TTSOpsVirtual,
1030 : : eqfuncoids,
1031 : 1020 : node->collations,
1032 : 1020 : node->param_exprs,
1033 : : (PlanState *) mstate);
1034 : :
1618 1035 : 1020 : pfree(eqfuncoids);
1515 1036 : 1020 : mstate->mem_used = 0;
1037 : :
1038 : : /* Limit the total memory consumed by the cache to this */
1504 tgl@sss.pgh.pa.us 1039 : 1020 : mstate->mem_limit = get_hash_memory_limit();
1040 : :
1041 : : /* A memory context dedicated for the cache */
1515 drowley@postgresql.o 1042 : 1020 : mstate->tableContext = AllocSetContextCreate(CurrentMemoryContext,
1043 : : "MemoizeHashTable",
1044 : : ALLOCSET_DEFAULT_SIZES);
1045 : :
1046 : 1020 : dlist_init(&mstate->lru_list);
1047 : 1020 : mstate->last_tuple = NULL;
1048 : 1020 : mstate->entry = NULL;
1049 : :
1050 : : /*
1051 : : * Mark if we can assume the cache entry is completed after we get the
1052 : : * first record for it. Some callers might not call us again after
1053 : : * getting the first match. e.g. A join operator performing a unique join
1054 : : * is able to skip to the next outer tuple after getting the first
1055 : : * matching inner tuple. In this case, the cache entry is complete after
1056 : : * getting the first tuple. This allows us to mark it as so.
1057 : : */
1058 : 1020 : mstate->singlerow = node->singlerow;
1382 1059 : 1020 : mstate->keyparamids = node->keyparamids;
1060 : :
1061 : : /*
1062 : : * Record if the cache keys should be compared bit by bit, or logically
1063 : : * using the type's hash equality operator
1064 : : */
1065 : 1020 : mstate->binary_mode = node->binary_mode;
1066 : :
1067 : : /* Zero the statistics counters */
1515 1068 : 1020 : memset(&mstate->stats, 0, sizeof(MemoizeInstrumentation));
1069 : :
1070 : : /*
1071 : : * Because it may require a large allocation, we delay building of the
1072 : : * hash table until executor run.
1073 : : */
585 1074 : 1020 : mstate->hashtable = NULL;
1075 : :
1515 1076 : 1020 : return mstate;
1077 : : }
1078 : :
1079 : : void
1080 : 1020 : ExecEndMemoize(MemoizeState *node)
1081 : : {
1082 : : #ifdef USE_ASSERT_CHECKING
1083 : : /* Validate the memory accounting code is correct in assert builds. */
585 1084 [ + + ]: 1020 : if (node->hashtable != NULL)
1085 : : {
1086 : : int count;
1581 1087 : 827 : uint64 mem = 0;
1088 : : memoize_iterator i;
1089 : : MemoizeEntry *entry;
1090 : :
1515 1091 : 827 : memoize_start_iterate(node->hashtable, &i);
1092 : :
1581 1093 : 827 : count = 0;
1515 1094 [ + + ]: 46940 : while ((entry = memoize_iterate(node->hashtable, &i)) != NULL)
1095 : : {
1096 : 46113 : MemoizeTuple *tuple = entry->tuplehead;
1097 : :
1581 1098 : 46113 : mem += EMPTY_ENTRY_MEMORY_BYTES(entry);
1099 [ + + ]: 89756 : while (tuple != NULL)
1100 : : {
1101 : 43643 : mem += CACHE_TUPLE_BYTES(tuple);
1102 : 43643 : tuple = tuple->next;
1103 : : }
1104 : 46113 : count++;
1105 : : }
1106 : :
1107 [ - + ]: 827 : Assert(count == node->hashtable->members);
1108 [ - + ]: 827 : Assert(mem == node->mem_used);
1109 : : }
1110 : : #endif
1111 : :
1112 : : /*
1113 : : * When ending a parallel worker, copy the statistics gathered by the
1114 : : * worker back into shared memory so that it can be picked up by the main
1115 : : * process to report in EXPLAIN ANALYZE.
1116 : : */
1618 1117 [ - + - - ]: 1020 : if (node->shared_info != NULL && IsParallelWorker())
1118 : : {
1119 : : MemoizeInstrumentation *si;
1120 : :
1121 : : /* Make mem_peak available for EXPLAIN */
1618 drowley@postgresql.o 1122 [ # # ]:UBC 0 : if (node->stats.mem_peak == 0)
1123 : 0 : node->stats.mem_peak = node->mem_used;
1124 : :
1125 [ # # ]: 0 : Assert(ParallelWorkerNumber <= node->shared_info->num_workers);
1126 : 0 : si = &node->shared_info->sinstrument[ParallelWorkerNumber];
1515 1127 : 0 : memcpy(si, &node->stats, sizeof(MemoizeInstrumentation));
1128 : : }
1129 : :
1130 : : /* Remove the cache context */
1618 drowley@postgresql.o 1131 :CBC 1020 : MemoryContextDelete(node->tableContext);
1132 : :
1133 : : /*
1134 : : * shut down the subplan
1135 : : */
1136 : 1020 : ExecEndNode(outerPlanState(node));
1137 : 1020 : }
1138 : :
1139 : : void
1515 1140 : 354212 : ExecReScanMemoize(MemoizeState *node)
1141 : : {
1618 1142 : 354212 : PlanState *outerPlan = outerPlanState(node);
1143 : :
1144 : : /* Mark that we must lookup the cache for a new set of parameters */
1515 1145 : 354212 : node->mstatus = MEMO_CACHE_LOOKUP;
1146 : :
1147 : : /* nullify pointers used for the last scan */
1618 1148 : 354212 : node->entry = NULL;
1149 : 354212 : node->last_tuple = NULL;
1150 : :
1151 : : /*
1152 : : * if chgParam of subnode is not null then plan will be re-scanned by
1153 : : * first ExecProcNode.
1154 : : */
1155 [ - + ]: 354212 : if (outerPlan->chgParam == NULL)
1618 drowley@postgresql.o 1156 :UBC 0 : ExecReScan(outerPlan);
1157 : :
1158 : : /*
1159 : : * Purge the entire cache if a parameter changed that is not part of the
1160 : : * cache key.
1161 : : */
1382 drowley@postgresql.o 1162 [ + + ]:CBC 354212 : if (bms_nonempty_difference(outerPlan->chgParam, node->keyparamids))
1163 : 9 : cache_purge_all(node);
1618 1164 : 354212 : }
1165 : :
1166 : : /*
1167 : : * ExecEstimateCacheEntryOverheadBytes
1168 : : * For use in the query planner to help it estimate the amount of memory
1169 : : * required to store a single entry in the cache.
1170 : : */
1171 : : double
1172 : 137108 : ExecEstimateCacheEntryOverheadBytes(double ntuples)
1173 : : {
1515 1174 : 137108 : return sizeof(MemoizeEntry) + sizeof(MemoizeKey) + sizeof(MemoizeTuple) *
1175 : : ntuples;
1176 : : }
1177 : :
1178 : : /* ----------------------------------------------------------------
1179 : : * Parallel Query Support
1180 : : * ----------------------------------------------------------------
1181 : : */
1182 : :
1183 : : /* ----------------------------------------------------------------
1184 : : * ExecMemoizeEstimate
1185 : : *
1186 : : * Estimate space required to propagate memoize statistics.
1187 : : * ----------------------------------------------------------------
1188 : : */
1189 : : void
1190 : 3 : ExecMemoizeEstimate(MemoizeState *node, ParallelContext *pcxt)
1191 : : {
1192 : : Size size;
1193 : :
1194 : : /* don't need this if not instrumenting or no workers */
1618 1195 [ - + - - ]: 3 : if (!node->ss.ps.instrument || pcxt->nworkers == 0)
1196 : 3 : return;
1197 : :
1515 drowley@postgresql.o 1198 :UBC 0 : size = mul_size(pcxt->nworkers, sizeof(MemoizeInstrumentation));
1199 : 0 : size = add_size(size, offsetof(SharedMemoizeInfo, sinstrument));
1618 1200 : 0 : shm_toc_estimate_chunk(&pcxt->estimator, size);
1201 : 0 : shm_toc_estimate_keys(&pcxt->estimator, 1);
1202 : : }
1203 : :
1204 : : /* ----------------------------------------------------------------
1205 : : * ExecMemoizeInitializeDSM
1206 : : *
1207 : : * Initialize DSM space for memoize statistics.
1208 : : * ----------------------------------------------------------------
1209 : : */
1210 : : void
1515 drowley@postgresql.o 1211 :CBC 3 : ExecMemoizeInitializeDSM(MemoizeState *node, ParallelContext *pcxt)
1212 : : {
1213 : : Size size;
1214 : :
1215 : : /* don't need this if not instrumenting or no workers */
1618 1216 [ - + - - ]: 3 : if (!node->ss.ps.instrument || pcxt->nworkers == 0)
1217 : 3 : return;
1218 : :
1515 drowley@postgresql.o 1219 :UBC 0 : size = offsetof(SharedMemoizeInfo, sinstrument)
1220 : 0 : + pcxt->nworkers * sizeof(MemoizeInstrumentation);
1618 1221 : 0 : node->shared_info = shm_toc_allocate(pcxt->toc, size);
1222 : : /* ensure any unfilled slots will contain zeroes */
1223 : 0 : memset(node->shared_info, 0, size);
1224 : 0 : node->shared_info->num_workers = pcxt->nworkers;
1225 : 0 : shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id,
1226 : 0 : node->shared_info);
1227 : : }
1228 : :
1229 : : /* ----------------------------------------------------------------
1230 : : * ExecMemoizeInitializeWorker
1231 : : *
1232 : : * Attach worker to DSM space for memoize statistics.
1233 : : * ----------------------------------------------------------------
1234 : : */
1235 : : void
1515 drowley@postgresql.o 1236 :CBC 6 : ExecMemoizeInitializeWorker(MemoizeState *node, ParallelWorkerContext *pwcxt)
1237 : : {
1618 1238 : 6 : node->shared_info =
1239 : 6 : shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, true);
1240 : 6 : }
1241 : :
1242 : : /* ----------------------------------------------------------------
1243 : : * ExecMemoizeRetrieveInstrumentation
1244 : : *
1245 : : * Transfer memoize statistics from DSM to private memory.
1246 : : * ----------------------------------------------------------------
1247 : : */
1248 : : void
1515 drowley@postgresql.o 1249 :UBC 0 : ExecMemoizeRetrieveInstrumentation(MemoizeState *node)
1250 : : {
1251 : : Size size;
1252 : : SharedMemoizeInfo *si;
1253 : :
1618 1254 [ # # ]: 0 : if (node->shared_info == NULL)
1255 : 0 : return;
1256 : :
1515 1257 : 0 : size = offsetof(SharedMemoizeInfo, sinstrument)
1258 : 0 : + node->shared_info->num_workers * sizeof(MemoizeInstrumentation);
1618 1259 : 0 : si = palloc(size);
1260 : 0 : memcpy(si, node->shared_info, size);
1261 : 0 : node->shared_info = si;
1262 : : }
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