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Cache NO ACTION foreign keys separately from RESTRICT foreign keys
[pgsql.git] / src / backend / utils / cache / catcache.c
blob9ad7681f1555200fb96b3cf24c9197af2208953c
1 /*-------------------------------------------------------------------------
2 *
3 * catcache.c
4 * System catalog cache for tuples matching a key.
5 *
6 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/utils/cache/catcache.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "access/genam.h"
18 #include "access/heaptoast.h"
19 #include "access/relscan.h"
20 #include "access/table.h"
21 #include "access/xact.h"
22 #include "catalog/catalog.h"
23 #include "catalog/pg_collation.h"
24 #include "catalog/pg_type.h"
25 #include "common/hashfn.h"
26 #include "common/pg_prng.h"
27 #include "miscadmin.h"
28 #include "port/pg_bitutils.h"
29 #ifdef CATCACHE_STATS
30 #include "storage/ipc.h" /* for on_proc_exit */
31 #endif
32 #include "storage/lmgr.h"
33 #include "utils/builtins.h"
34 #include "utils/catcache.h"
35 #include "utils/datum.h"
36 #include "utils/fmgroids.h"
37 #include "utils/injection_point.h"
38 #include "utils/inval.h"
39 #include "utils/memutils.h"
40 #include "utils/rel.h"
41 #include "utils/resowner.h"
42 #include "utils/syscache.h"
43
44 /*
45 * If a catcache invalidation is processed while we are in the middle of
46 * creating a catcache entry (or list), it might apply to the entry we're
47 * creating, making it invalid before it's been inserted to the catcache. To
48 * catch such cases, we have a stack of "create-in-progress" entries. Cache
49 * invalidation marks any matching entries in the stack as dead, in addition
50 * to the actual CatCTup and CatCList entries.
51 */
52 typedef struct CatCInProgress
53 {
54 CatCache *cache; /* cache that the entry belongs to */
55 uint32 hash_value; /* hash of the entry; ignored for lists */
56 bool list; /* is it a list entry? */
57 bool dead; /* set when the entry is invalidated */
58 struct CatCInProgress *next;
59 } CatCInProgress;
60
61 static CatCInProgress *catcache_in_progress_stack = NULL;
62
63 /* #define CACHEDEBUG */ /* turns DEBUG elogs on */
64
65 /*
66 * Given a hash value and the size of the hash table, find the bucket
67 * in which the hash value belongs. Since the hash table must contain
68 * a power-of-2 number of elements, this is a simple bitmask.
69 */
70 #define HASH_INDEX(h, sz) ((Index) ((h) & ((sz) - 1)))
71
72
73 /*
74 * variables, macros and other stuff
75 */
76
77 #ifdef CACHEDEBUG
78 #define CACHE_elog(...) elog(__VA_ARGS__)
79 #else
80 #define CACHE_elog(...)
81 #endif
82
83 /* Cache management header --- pointer is NULL until created */
84 static CatCacheHeader *CacheHdr = NULL;
85
86 static inline HeapTuple SearchCatCacheInternal(CatCache *cache,
87 int nkeys,
88 Datum v1, Datum v2,
89 Datum v3, Datum v4);
90
91 static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache,
92 int nkeys,
93 uint32 hashValue,
94 Index hashIndex,
95 Datum v1, Datum v2,
96 Datum v3, Datum v4);
97
98 static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys,
99 Datum v1, Datum v2, Datum v3, Datum v4);
100 static uint32 CatalogCacheComputeTupleHashValue(CatCache *cache, int nkeys,
101 HeapTuple tuple);
102 static inline bool CatalogCacheCompareTuple(const CatCache *cache, int nkeys,
103 const Datum *cachekeys,
104 const Datum *searchkeys);
105
106 #ifdef CATCACHE_STATS
107 static void CatCachePrintStats(int code, Datum arg);
108 #endif
109 static void CatCacheRemoveCTup(CatCache *cache, CatCTup *ct);
110 static void CatCacheRemoveCList(CatCache *cache, CatCList *cl);
111 static void RehashCatCache(CatCache *cp);
112 static void RehashCatCacheLists(CatCache *cp);
113 static void CatalogCacheInitializeCache(CatCache *cache);
114 static CatCTup *CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp,
115 Datum *arguments,
116 uint32 hashValue, Index hashIndex);
117
118 static void ReleaseCatCacheWithOwner(HeapTuple tuple, ResourceOwner resowner);
119 static void ReleaseCatCacheListWithOwner(CatCList *list, ResourceOwner resowner);
120 static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos,
121 Datum *keys);
122 static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos,
123 Datum *srckeys, Datum *dstkeys);
124
125
126 /*
127 * internal support functions
128 */
129
130 /* ResourceOwner callbacks to hold catcache references */
131
132 static void ResOwnerReleaseCatCache(Datum res);
133 static char *ResOwnerPrintCatCache(Datum res);
134 static void ResOwnerReleaseCatCacheList(Datum res);
135 static char *ResOwnerPrintCatCacheList(Datum res);
136
137 static const ResourceOwnerDesc catcache_resowner_desc =
138 {
139 /* catcache references */
140 .name = "catcache reference",
141 .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
142 .release_priority = RELEASE_PRIO_CATCACHE_REFS,
143 .ReleaseResource = ResOwnerReleaseCatCache,
144 .DebugPrint = ResOwnerPrintCatCache
145 };
146
147 static const ResourceOwnerDesc catlistref_resowner_desc =
148 {
149 /* catcache-list pins */
150 .name = "catcache list reference",
151 .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
152 .release_priority = RELEASE_PRIO_CATCACHE_LIST_REFS,
153 .ReleaseResource = ResOwnerReleaseCatCacheList,
154 .DebugPrint = ResOwnerPrintCatCacheList
155 };
156
157 /* Convenience wrappers over ResourceOwnerRemember/Forget */
158 static inline void
159 ResourceOwnerRememberCatCacheRef(ResourceOwner owner, HeapTuple tuple)
160 {
161 ResourceOwnerRemember(owner, PointerGetDatum(tuple), &catcache_resowner_desc);
162 }
163 static inline void
164 ResourceOwnerForgetCatCacheRef(ResourceOwner owner, HeapTuple tuple)
165 {
166 ResourceOwnerForget(owner, PointerGetDatum(tuple), &catcache_resowner_desc);
167 }
168 static inline void
169 ResourceOwnerRememberCatCacheListRef(ResourceOwner owner, CatCList *list)
170 {
171 ResourceOwnerRemember(owner, PointerGetDatum(list), &catlistref_resowner_desc);
172 }
173 static inline void
174 ResourceOwnerForgetCatCacheListRef(ResourceOwner owner, CatCList *list)
175 {
176 ResourceOwnerForget(owner, PointerGetDatum(list), &catlistref_resowner_desc);
177 }
178
179
180 /*
181 * Hash and equality functions for system types that are used as cache key
182 * fields. In some cases, we just call the regular SQL-callable functions for
183 * the appropriate data type, but that tends to be a little slow, and the
184 * speed of these functions is performance-critical. Therefore, for data
185 * types that frequently occur as catcache keys, we hard-code the logic here.
186 * Avoiding the overhead of DirectFunctionCallN(...) is a substantial win, and
187 * in certain cases (like int4) we can adopt a faster hash algorithm as well.
188 */
189
190 static bool
191 chareqfast(Datum a, Datum b)
192 {
193 return DatumGetChar(a) == DatumGetChar(b);
194 }
195
196 static uint32
197 charhashfast(Datum datum)
198 {
199 return murmurhash32((int32) DatumGetChar(datum));
200 }
201
202 static bool
203 nameeqfast(Datum a, Datum b)
204 {
205 char *ca = NameStr(*DatumGetName(a));
206 char *cb = NameStr(*DatumGetName(b));
207
208 return strncmp(ca, cb, NAMEDATALEN) == 0;
209 }
210
211 static uint32
212 namehashfast(Datum datum)
213 {
214 char *key = NameStr(*DatumGetName(datum));
215
216 return hash_any((unsigned char *) key, strlen(key));
217 }
218
219 static bool
220 int2eqfast(Datum a, Datum b)
221 {
222 return DatumGetInt16(a) == DatumGetInt16(b);
223 }
224
225 static uint32
226 int2hashfast(Datum datum)
227 {
228 return murmurhash32((int32) DatumGetInt16(datum));
229 }
230
231 static bool
232 int4eqfast(Datum a, Datum b)
233 {
234 return DatumGetInt32(a) == DatumGetInt32(b);
235 }
236
237 static uint32
238 int4hashfast(Datum datum)
239 {
240 return murmurhash32((int32) DatumGetInt32(datum));
241 }
242
243 static bool
244 texteqfast(Datum a, Datum b)
245 {
246 /*
247 * The use of DEFAULT_COLLATION_OID is fairly arbitrary here. We just
248 * want to take the fast "deterministic" path in texteq().
249 */
250 return DatumGetBool(DirectFunctionCall2Coll(texteq, DEFAULT_COLLATION_OID, a, b));
251 }
252
253 static uint32
254 texthashfast(Datum datum)
255 {
256 /* analogously here as in texteqfast() */
257 return DatumGetInt32(DirectFunctionCall1Coll(hashtext, DEFAULT_COLLATION_OID, datum));
258 }
259
260 static bool
261 oidvectoreqfast(Datum a, Datum b)
262 {
263 return DatumGetBool(DirectFunctionCall2(oidvectoreq, a, b));
264 }
265
266 static uint32
267 oidvectorhashfast(Datum datum)
268 {
269 return DatumGetInt32(DirectFunctionCall1(hashoidvector, datum));
270 }
271
272 /* Lookup support functions for a type. */
273 static void
274 GetCCHashEqFuncs(Oid keytype, CCHashFN *hashfunc, RegProcedure *eqfunc, CCFastEqualFN *fasteqfunc)
275 {
276 switch (keytype)
277 {
278 case BOOLOID:
279 *hashfunc = charhashfast;
280 *fasteqfunc = chareqfast;
281 *eqfunc = F_BOOLEQ;
282 break;
283 case CHAROID:
284 *hashfunc = charhashfast;
285 *fasteqfunc = chareqfast;
286 *eqfunc = F_CHAREQ;
287 break;
288 case NAMEOID:
289 *hashfunc = namehashfast;
290 *fasteqfunc = nameeqfast;
291 *eqfunc = F_NAMEEQ;
292 break;
293 case INT2OID:
294 *hashfunc = int2hashfast;
295 *fasteqfunc = int2eqfast;
296 *eqfunc = F_INT2EQ;
297 break;
298 case INT4OID:
299 *hashfunc = int4hashfast;
300 *fasteqfunc = int4eqfast;
301 *eqfunc = F_INT4EQ;
302 break;
303 case TEXTOID:
304 *hashfunc = texthashfast;
305 *fasteqfunc = texteqfast;
306 *eqfunc = F_TEXTEQ;
307 break;
308 case OIDOID:
309 case REGPROCOID:
310 case REGPROCEDUREOID:
311 case REGOPEROID:
312 case REGOPERATOROID:
313 case REGCLASSOID:
314 case REGTYPEOID:
315 case REGCOLLATIONOID:
316 case REGCONFIGOID:
317 case REGDICTIONARYOID:
318 case REGROLEOID:
319 case REGNAMESPACEOID:
320 *hashfunc = int4hashfast;
321 *fasteqfunc = int4eqfast;
322 *eqfunc = F_OIDEQ;
323 break;
324 case OIDVECTOROID:
325 *hashfunc = oidvectorhashfast;
326 *fasteqfunc = oidvectoreqfast;
327 *eqfunc = F_OIDVECTOREQ;
328 break;
329 default:
330 elog(FATAL, "type %u not supported as catcache key", keytype);
331 *hashfunc = NULL; /* keep compiler quiet */
332
333 *eqfunc = InvalidOid;
334 break;
335 }
336 }
337
338 /*
339 * CatalogCacheComputeHashValue
340 *
341 * Compute the hash value associated with a given set of lookup keys
342 */
343 static uint32
344 CatalogCacheComputeHashValue(CatCache *cache, int nkeys,
345 Datum v1, Datum v2, Datum v3, Datum v4)
346 {
347 uint32 hashValue = 0;
348 uint32 oneHash;
349 CCHashFN *cc_hashfunc = cache->cc_hashfunc;
350
351 CACHE_elog(DEBUG2, "CatalogCacheComputeHashValue %s %d %p",
352 cache->cc_relname, nkeys, cache);
353
354 switch (nkeys)
355 {
356 case 4:
357 oneHash = (cc_hashfunc[3]) (v4);
358 hashValue ^= pg_rotate_left32(oneHash, 24);
359 /* FALLTHROUGH */
360 case 3:
361 oneHash = (cc_hashfunc[2]) (v3);
362 hashValue ^= pg_rotate_left32(oneHash, 16);
363 /* FALLTHROUGH */
364 case 2:
365 oneHash = (cc_hashfunc[1]) (v2);
366 hashValue ^= pg_rotate_left32(oneHash, 8);
367 /* FALLTHROUGH */
368 case 1:
369 oneHash = (cc_hashfunc[0]) (v1);
370 hashValue ^= oneHash;
371 break;
372 default:
373 elog(FATAL, "wrong number of hash keys: %d", nkeys);
374 break;
375 }
376
377 return hashValue;
378 }
379
380 /*
381 * CatalogCacheComputeTupleHashValue
382 *
383 * Compute the hash value associated with a given tuple to be cached
384 */
385 static uint32
386 CatalogCacheComputeTupleHashValue(CatCache *cache, int nkeys, HeapTuple tuple)
387 {
388 Datum v1 = 0,
389 v2 = 0,
390 v3 = 0,
391 v4 = 0;
392 bool isNull = false;
393 int *cc_keyno = cache->cc_keyno;
394 TupleDesc cc_tupdesc = cache->cc_tupdesc;
395
396 /* Now extract key fields from tuple, insert into scankey */
397 switch (nkeys)
398 {
399 case 4:
400 v4 = fastgetattr(tuple,
401 cc_keyno[3],
402 cc_tupdesc,
403 &isNull);
404 Assert(!isNull);
405 /* FALLTHROUGH */
406 case 3:
407 v3 = fastgetattr(tuple,
408 cc_keyno[2],
409 cc_tupdesc,
410 &isNull);
411 Assert(!isNull);
412 /* FALLTHROUGH */
413 case 2:
414 v2 = fastgetattr(tuple,
415 cc_keyno[1],
416 cc_tupdesc,
417 &isNull);
418 Assert(!isNull);
419 /* FALLTHROUGH */
420 case 1:
421 v1 = fastgetattr(tuple,
422 cc_keyno[0],
423 cc_tupdesc,
424 &isNull);
425 Assert(!isNull);
426 break;
427 default:
428 elog(FATAL, "wrong number of hash keys: %d", nkeys);
429 break;
430 }
431
432 return CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4);
433 }
434
435 /*
436 * CatalogCacheCompareTuple
437 *
438 * Compare a tuple to the passed arguments.
439 */
440 static inline bool
441 CatalogCacheCompareTuple(const CatCache *cache, int nkeys,
442 const Datum *cachekeys,
443 const Datum *searchkeys)
444 {
445 const CCFastEqualFN *cc_fastequal = cache->cc_fastequal;
446 int i;
447
448 for (i = 0; i < nkeys; i++)
449 {
450 if (!(cc_fastequal[i]) (cachekeys[i], searchkeys[i]))
451 return false;
452 }
453 return true;
454 }
455
456
457 #ifdef CATCACHE_STATS
458
459 static void
460 CatCachePrintStats(int code, Datum arg)
461 {
462 slist_iter iter;
463 long cc_searches = 0;
464 long cc_hits = 0;
465 long cc_neg_hits = 0;
466 long cc_newloads = 0;
467 long cc_invals = 0;
468 long cc_nlists = 0;
469 long cc_lsearches = 0;
470 long cc_lhits = 0;
471
472 slist_foreach(iter, &CacheHdr->ch_caches)
473 {
474 CatCache *cache = slist_container(CatCache, cc_next, iter.cur);
475
476 if (cache->cc_ntup == 0 && cache->cc_searches == 0)
477 continue; /* don't print unused caches */
478 elog(DEBUG2, "catcache %s/%u: %d tup, %ld srch, %ld+%ld=%ld hits, %ld+%ld=%ld loads, %ld invals, %d lists, %ld lsrch, %ld lhits",
479 cache->cc_relname,
480 cache->cc_indexoid,
481 cache->cc_ntup,
482 cache->cc_searches,
483 cache->cc_hits,
484 cache->cc_neg_hits,
485 cache->cc_hits + cache->cc_neg_hits,
486 cache->cc_newloads,
487 cache->cc_searches - cache->cc_hits - cache->cc_neg_hits - cache->cc_newloads,
488 cache->cc_searches - cache->cc_hits - cache->cc_neg_hits,
489 cache->cc_invals,
490 cache->cc_nlist,
491 cache->cc_lsearches,
492 cache->cc_lhits);
493 cc_searches += cache->cc_searches;
494 cc_hits += cache->cc_hits;
495 cc_neg_hits += cache->cc_neg_hits;
496 cc_newloads += cache->cc_newloads;
497 cc_invals += cache->cc_invals;
498 cc_nlists += cache->cc_nlist;
499 cc_lsearches += cache->cc_lsearches;
500 cc_lhits += cache->cc_lhits;
501 }
502 elog(DEBUG2, "catcache totals: %d tup, %ld srch, %ld+%ld=%ld hits, %ld+%ld=%ld loads, %ld invals, %ld lists, %ld lsrch, %ld lhits",
503 CacheHdr->ch_ntup,
504 cc_searches,
505 cc_hits,
506 cc_neg_hits,
507 cc_hits + cc_neg_hits,
508 cc_newloads,
509 cc_searches - cc_hits - cc_neg_hits - cc_newloads,
510 cc_searches - cc_hits - cc_neg_hits,
511 cc_invals,
512 cc_nlists,
513 cc_lsearches,
514 cc_lhits);
515 }
516 #endif /* CATCACHE_STATS */
517
518
519 /*
520 * CatCacheRemoveCTup
521 *
522 * Unlink and delete the given cache entry
523 *
524 * NB: if it is a member of a CatCList, the CatCList is deleted too.
525 * Both the cache entry and the list had better have zero refcount.
526 */
527 static void
528 CatCacheRemoveCTup(CatCache *cache, CatCTup *ct)
529 {
530 Assert(ct->refcount == 0);
531 Assert(ct->my_cache == cache);
532
533 if (ct->c_list)
534 {
535 /*
536 * The cleanest way to handle this is to call CatCacheRemoveCList,
537 * which will recurse back to me, and the recursive call will do the
538 * work. Set the "dead" flag to make sure it does recurse.
539 */
540 ct->dead = true;
541 CatCacheRemoveCList(cache, ct->c_list);
542 return; /* nothing left to do */
543 }
544
545 /* delink from linked list */
546 dlist_delete(&ct->cache_elem);
547
548 /*
549 * Free keys when we're dealing with a negative entry, normal entries just
550 * point into tuple, allocated together with the CatCTup.
551 */
552 if (ct->negative)
553 CatCacheFreeKeys(cache->cc_tupdesc, cache->cc_nkeys,
554 cache->cc_keyno, ct->keys);
555
556 pfree(ct);
557
558 --cache->cc_ntup;
559 --CacheHdr->ch_ntup;
560 }
561
562 /*
563 * CatCacheRemoveCList
564 *
565 * Unlink and delete the given cache list entry
566 *
567 * NB: any dead member entries that become unreferenced are deleted too.
568 */
569 static void
570 CatCacheRemoveCList(CatCache *cache, CatCList *cl)
571 {
572 int i;
573
574 Assert(cl->refcount == 0);
575 Assert(cl->my_cache == cache);
576
577 /* delink from member tuples */
578 for (i = cl->n_members; --i >= 0;)
579 {
580 CatCTup *ct = cl->members[i];
581
582 Assert(ct->c_list == cl);
583 ct->c_list = NULL;
584 /* if the member is dead and now has no references, remove it */
585 if (
586 #ifndef CATCACHE_FORCE_RELEASE
587 ct->dead &&
588 #endif
589 ct->refcount == 0)
590 CatCacheRemoveCTup(cache, ct);
591 }
592
593 /* delink from linked list */
594 dlist_delete(&cl->cache_elem);
595
596 /* free associated column data */
597 CatCacheFreeKeys(cache->cc_tupdesc, cl->nkeys,
598 cache->cc_keyno, cl->keys);
599
600 pfree(cl);
601
602 --cache->cc_nlist;
603 }
604
605
606 /*
607 * CatCacheInvalidate
608 *
609 * Invalidate entries in the specified cache, given a hash value.
610 *
611 * We delete cache entries that match the hash value, whether positive
612 * or negative. We don't care whether the invalidation is the result
613 * of a tuple insertion or a deletion.
614 *
615 * We used to try to match positive cache entries by TID, but that is
616 * unsafe after a VACUUM FULL on a system catalog: an inval event could
617 * be queued before VACUUM FULL, and then processed afterwards, when the
618 * target tuple that has to be invalidated has a different TID than it
619 * did when the event was created. So now we just compare hash values and
620 * accept the small risk of unnecessary invalidations due to false matches.
621 *
622 * This routine is only quasi-public: it should only be used by inval.c.
623 */
624 void
625 CatCacheInvalidate(CatCache *cache, uint32 hashValue)
626 {
627 Index hashIndex;
628 dlist_mutable_iter iter;
629
630 CACHE_elog(DEBUG2, "CatCacheInvalidate: called");
631
632 /*
633 * We don't bother to check whether the cache has finished initialization
634 * yet; if not, there will be no entries in it so no problem.
635 */
636
637 /*
638 * Invalidate *all* CatCLists in this cache; it's too hard to tell which
639 * searches might still be correct, so just zap 'em all.
640 */
641 for (int i = 0; i < cache->cc_nlbuckets; i++)
642 {
643 dlist_head *bucket = &cache->cc_lbucket[i];
644
645 dlist_foreach_modify(iter, bucket)
646 {
647 CatCList *cl = dlist_container(CatCList, cache_elem, iter.cur);
648
649 if (cl->refcount > 0)
650 cl->dead = true;
651 else
652 CatCacheRemoveCList(cache, cl);
653 }
654 }
655
656 /*
657 * inspect the proper hash bucket for tuple matches
658 */
659 hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets);
660 dlist_foreach_modify(iter, &cache->cc_bucket[hashIndex])
661 {
662 CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur);
663
664 if (hashValue == ct->hash_value)
665 {
666 if (ct->refcount > 0 ||
667 (ct->c_list && ct->c_list->refcount > 0))
668 {
669 ct->dead = true;
670 /* list, if any, was marked dead above */
671 Assert(ct->c_list == NULL || ct->c_list->dead);
672 }
673 else
674 CatCacheRemoveCTup(cache, ct);
675 CACHE_elog(DEBUG2, "CatCacheInvalidate: invalidated");
676 #ifdef CATCACHE_STATS
677 cache->cc_invals++;
678 #endif
679 /* could be multiple matches, so keep looking! */
680 }
681 }
682
683 /* Also invalidate any entries that are being built */
684 for (CatCInProgress *e = catcache_in_progress_stack; e != NULL; e = e->next)
685 {
686 if (e->cache == cache)
687 {
688 if (e->list || e->hash_value == hashValue)
689 e->dead = true;
690 }
691 }
692 }
693
694 /* ----------------------------------------------------------------
695 * public functions
696 * ----------------------------------------------------------------
697 */
698
699
700 /*
701 * Standard routine for creating cache context if it doesn't exist yet
702 *
703 * There are a lot of places (probably far more than necessary) that check
704 * whether CacheMemoryContext exists yet and want to create it if not.
705 * We centralize knowledge of exactly how to create it here.
706 */
707 void
708 CreateCacheMemoryContext(void)
709 {
710 /*
711 * Purely for paranoia, check that context doesn't exist; caller probably
712 * did so already.
713 */
714 if (!CacheMemoryContext)
715 CacheMemoryContext = AllocSetContextCreate(TopMemoryContext,
716 "CacheMemoryContext",
717 ALLOCSET_DEFAULT_SIZES);
718 }
719
720
721 /*
722 * ResetCatalogCache
723 *
724 * Reset one catalog cache to empty.
725 *
726 * This is not very efficient if the target cache is nearly empty.
727 * However, it shouldn't need to be efficient; we don't invoke it often.
728 *
729 * If 'debug_discard' is true, we are being called as part of
730 * debug_discard_caches. In that case, the cache is not reset for
731 * correctness, but just to get more testing of cache invalidation. We skip
732 * resetting in-progress build entries in that case, or we'd never make any
733 * progress.
734 */
735 static void
736 ResetCatalogCache(CatCache *cache, bool debug_discard)
737 {
738 dlist_mutable_iter iter;
739 int i;
740
741 /* Remove each list in this cache, or at least mark it dead */
742 for (i = 0; i < cache->cc_nlbuckets; i++)
743 {
744 dlist_head *bucket = &cache->cc_lbucket[i];
745
746 dlist_foreach_modify(iter, bucket)
747 {
748 CatCList *cl = dlist_container(CatCList, cache_elem, iter.cur);
749
750 if (cl->refcount > 0)
751 cl->dead = true;
752 else
753 CatCacheRemoveCList(cache, cl);
754 }
755 }
756
757 /* Remove each tuple in this cache, or at least mark it dead */
758 for (i = 0; i < cache->cc_nbuckets; i++)
759 {
760 dlist_head *bucket = &cache->cc_bucket[i];
761
762 dlist_foreach_modify(iter, bucket)
763 {
764 CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur);
765
766 if (ct->refcount > 0 ||
767 (ct->c_list && ct->c_list->refcount > 0))
768 {
769 ct->dead = true;
770 /* list, if any, was marked dead above */
771 Assert(ct->c_list == NULL || ct->c_list->dead);
772 }
773 else
774 CatCacheRemoveCTup(cache, ct);
775 #ifdef CATCACHE_STATS
776 cache->cc_invals++;
777 #endif
778 }
779 }
780
781 /* Also invalidate any entries that are being built */
782 if (!debug_discard)
783 {
784 for (CatCInProgress *e = catcache_in_progress_stack; e != NULL; e = e->next)
785 {
786 if (e->cache == cache)
787 e->dead = true;
788 }
789 }
790 }
791
792 /*
793 * ResetCatalogCaches
794 *
795 * Reset all caches when a shared cache inval event forces it
796 */
797 void
798 ResetCatalogCaches(void)
799 {
800 ResetCatalogCachesExt(false);
801 }
802
803 void
804 ResetCatalogCachesExt(bool debug_discard)
805 {
806 slist_iter iter;
807
808 CACHE_elog(DEBUG2, "ResetCatalogCaches called");
809
810 slist_foreach(iter, &CacheHdr->ch_caches)
811 {
812 CatCache *cache = slist_container(CatCache, cc_next, iter.cur);
813
814 ResetCatalogCache(cache, debug_discard);
815 }
816
817 CACHE_elog(DEBUG2, "end of ResetCatalogCaches call");
818 }
819
820 /*
821 * CatalogCacheFlushCatalog
822 *
823 * Flush all catcache entries that came from the specified system catalog.
824 * This is needed after VACUUM FULL/CLUSTER on the catalog, since the
825 * tuples very likely now have different TIDs than before. (At one point
826 * we also tried to force re-execution of CatalogCacheInitializeCache for
827 * the cache(s) on that catalog. This is a bad idea since it leads to all
828 * kinds of trouble if a cache flush occurs while loading cache entries.
829 * We now avoid the need to do it by copying cc_tupdesc out of the relcache,
830 * rather than relying on the relcache to keep a tupdesc for us. Of course
831 * this assumes the tupdesc of a cachable system table will not change...)
832 */
833 void
834 CatalogCacheFlushCatalog(Oid catId)
835 {
836 slist_iter iter;
837
838 CACHE_elog(DEBUG2, "CatalogCacheFlushCatalog called for %u", catId);
839
840 slist_foreach(iter, &CacheHdr->ch_caches)
841 {
842 CatCache *cache = slist_container(CatCache, cc_next, iter.cur);
843
844 /* Does this cache store tuples of the target catalog? */
845 if (cache->cc_reloid == catId)
846 {
847 /* Yes, so flush all its contents */
848 ResetCatalogCache(cache, false);
849
850 /* Tell inval.c to call syscache callbacks for this cache */
851 CallSyscacheCallbacks(cache->id, 0);
852 }
853 }
854
855 CACHE_elog(DEBUG2, "end of CatalogCacheFlushCatalog call");
856 }
857
858 /*
859 * InitCatCache
860 *
861 * This allocates and initializes a cache for a system catalog relation.
862 * Actually, the cache is only partially initialized to avoid opening the
863 * relation. The relation will be opened and the rest of the cache
864 * structure initialized on the first access.
865 */
866 #ifdef CACHEDEBUG
867 #define InitCatCache_DEBUG2 \
868 do { \
869 elog(DEBUG2, "InitCatCache: rel=%u ind=%u id=%d nkeys=%d size=%d", \
870 cp->cc_reloid, cp->cc_indexoid, cp->id, \
871 cp->cc_nkeys, cp->cc_nbuckets); \
872 } while(0)
873 #else
874 #define InitCatCache_DEBUG2
875 #endif
876
877 CatCache *
878 InitCatCache(int id,
879 Oid reloid,
880 Oid indexoid,
881 int nkeys,
882 const int *key,
883 int nbuckets)
884 {
885 CatCache *cp;
886 MemoryContext oldcxt;
887 int i;
888
889 /*
890 * nbuckets is the initial number of hash buckets to use in this catcache.
891 * It will be enlarged later if it becomes too full.
892 *
893 * nbuckets must be a power of two. We check this via Assert rather than
894 * a full runtime check because the values will be coming from constant
895 * tables.
896 *
897 * If you're confused by the power-of-two check, see comments in
898 * bitmapset.c for an explanation.
899 */
900 Assert(nbuckets > 0 && (nbuckets & -nbuckets) == nbuckets);
901
902 /*
903 * first switch to the cache context so our allocations do not vanish at
904 * the end of a transaction
905 */
906 if (!CacheMemoryContext)
907 CreateCacheMemoryContext();
908
909 oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
910
911 /*
912 * if first time through, initialize the cache group header
913 */
914 if (CacheHdr == NULL)
915 {
916 CacheHdr = (CatCacheHeader *) palloc(sizeof(CatCacheHeader));
917 slist_init(&CacheHdr->ch_caches);
918 CacheHdr->ch_ntup = 0;
919 #ifdef CATCACHE_STATS
920 /* set up to dump stats at backend exit */
921 on_proc_exit(CatCachePrintStats, 0);
922 #endif
923 }
924
925 /*
926 * Allocate a new cache structure, aligning to a cacheline boundary
927 *
928 * Note: we rely on zeroing to initialize all the dlist headers correctly
929 */
930 cp = (CatCache *) palloc_aligned(sizeof(CatCache), PG_CACHE_LINE_SIZE,
931 MCXT_ALLOC_ZERO);
932 cp->cc_bucket = palloc0(nbuckets * sizeof(dlist_head));
933
934 /*
935 * Many catcaches never receive any list searches. Therefore, we don't
936 * allocate the cc_lbuckets till we get a list search.
937 */
938 cp->cc_lbucket = NULL;
939
940 /*
941 * initialize the cache's relation information for the relation
942 * corresponding to this cache, and initialize some of the new cache's
943 * other internal fields. But don't open the relation yet.
944 */
945 cp->id = id;
946 cp->cc_relname = "(not known yet)";
947 cp->cc_reloid = reloid;
948 cp->cc_indexoid = indexoid;
949 cp->cc_relisshared = false; /* temporary */
950 cp->cc_tupdesc = (TupleDesc) NULL;
951 cp->cc_ntup = 0;
952 cp->cc_nlist = 0;
953 cp->cc_nbuckets = nbuckets;
954 cp->cc_nlbuckets = 0;
955 cp->cc_nkeys = nkeys;
956 for (i = 0; i < nkeys; ++i)
957 {
958 Assert(AttributeNumberIsValid(key[i]));
959 cp->cc_keyno[i] = key[i];
960 }
961
962 /*
963 * new cache is initialized as far as we can go for now. print some
964 * debugging information, if appropriate.
965 */
966 InitCatCache_DEBUG2;
967
968 /*
969 * add completed cache to top of group header's list
970 */
971 slist_push_head(&CacheHdr->ch_caches, &cp->cc_next);
972
973 /*
974 * back to the old context before we return...
975 */
976 MemoryContextSwitchTo(oldcxt);
977
978 return cp;
979 }
980
981 /*
982 * Enlarge a catcache, doubling the number of buckets.
983 */
984 static void
985 RehashCatCache(CatCache *cp)
986 {
987 dlist_head *newbucket;
988 int newnbuckets;
989 int i;
990
991 elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets",
992 cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets);
993
994 /* Allocate a new, larger, hash table. */
995 newnbuckets = cp->cc_nbuckets * 2;
996 newbucket = (dlist_head *) MemoryContextAllocZero(CacheMemoryContext, newnbuckets * sizeof(dlist_head));
997
998 /* Move all entries from old hash table to new. */
999 for (i = 0; i < cp->cc_nbuckets; i++)
1000 {
1001 dlist_mutable_iter iter;
1002
1003 dlist_foreach_modify(iter, &cp->cc_bucket[i])
1004 {
1005 CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur);
1006 int hashIndex = HASH_INDEX(ct->hash_value, newnbuckets);
1007
1008 dlist_delete(iter.cur);
1009 dlist_push_head(&newbucket[hashIndex], &ct->cache_elem);
1010 }
1011 }
1012
1013 /* Switch to the new array. */
1014 pfree(cp->cc_bucket);
1015 cp->cc_nbuckets = newnbuckets;
1016 cp->cc_bucket = newbucket;
1017 }
1018
1019 /*
1020 * Enlarge a catcache's list storage, doubling the number of buckets.
1021 */
1022 static void
1023 RehashCatCacheLists(CatCache *cp)
1024 {
1025 dlist_head *newbucket;
1026 int newnbuckets;
1027 int i;
1028
1029 elog(DEBUG1, "rehashing catalog cache id %d for %s; %d lists, %d buckets",
1030 cp->id, cp->cc_relname, cp->cc_nlist, cp->cc_nlbuckets);
1031
1032 /* Allocate a new, larger, hash table. */
1033 newnbuckets = cp->cc_nlbuckets * 2;
1034 newbucket = (dlist_head *) MemoryContextAllocZero(CacheMemoryContext, newnbuckets * sizeof(dlist_head));
1035
1036 /* Move all entries from old hash table to new. */
1037 for (i = 0; i < cp->cc_nlbuckets; i++)
1038 {
1039 dlist_mutable_iter iter;
1040
1041 dlist_foreach_modify(iter, &cp->cc_lbucket[i])
1042 {
1043 CatCList *cl = dlist_container(CatCList, cache_elem, iter.cur);
1044 int hashIndex = HASH_INDEX(cl->hash_value, newnbuckets);
1045
1046 dlist_delete(iter.cur);
1047 dlist_push_head(&newbucket[hashIndex], &cl->cache_elem);
1048 }
1049 }
1050
1051 /* Switch to the new array. */
1052 pfree(cp->cc_lbucket);
1053 cp->cc_nlbuckets = newnbuckets;
1054 cp->cc_lbucket = newbucket;
1055 }
1056
1057 /*
1058 * CatalogCacheInitializeCache
1059 *
1060 * This function does final initialization of a catcache: obtain the tuple
1061 * descriptor and set up the hash and equality function links. We assume
1062 * that the relcache entry can be opened at this point!
1063 */
1064 #ifdef CACHEDEBUG
1065 #define CatalogCacheInitializeCache_DEBUG1 \
1066 elog(DEBUG2, "CatalogCacheInitializeCache: cache @%p rel=%u", cache, \
1067 cache->cc_reloid)
1068
1069 #define CatalogCacheInitializeCache_DEBUG2 \
1070 do { \
1071 if (cache->cc_keyno[i] > 0) { \
1072 elog(DEBUG2, "CatalogCacheInitializeCache: load %d/%d w/%d, %u", \
1073 i+1, cache->cc_nkeys, cache->cc_keyno[i], \
1074 TupleDescAttr(tupdesc, cache->cc_keyno[i] - 1)->atttypid); \
1075 } else { \
1076 elog(DEBUG2, "CatalogCacheInitializeCache: load %d/%d w/%d", \
1077 i+1, cache->cc_nkeys, cache->cc_keyno[i]); \
1078 } \
1079 } while(0)
1080 #else
1081 #define CatalogCacheInitializeCache_DEBUG1
1082 #define CatalogCacheInitializeCache_DEBUG2
1083 #endif
1084
1085 static void
1086 CatalogCacheInitializeCache(CatCache *cache)
1087 {
1088 Relation relation;
1089 MemoryContext oldcxt;
1090 TupleDesc tupdesc;
1091 int i;
1092
1093 CatalogCacheInitializeCache_DEBUG1;
1094
1095 relation = table_open(cache->cc_reloid, AccessShareLock);
1096
1097 /*
1098 * switch to the cache context so our allocations do not vanish at the end
1099 * of a transaction
1100 */
1101 Assert(CacheMemoryContext != NULL);
1102
1103 oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
1104
1105 /*
1106 * copy the relcache's tuple descriptor to permanent cache storage
1107 */
1108 tupdesc = CreateTupleDescCopyConstr(RelationGetDescr(relation));
1109
1110 /*
1111 * save the relation's name and relisshared flag, too (cc_relname is used
1112 * only for debugging purposes)
1113 */
1114 cache->cc_relname = pstrdup(RelationGetRelationName(relation));
1115 cache->cc_relisshared = RelationGetForm(relation)->relisshared;
1116
1117 /*
1118 * return to the caller's memory context and close the rel
1119 */
1120 MemoryContextSwitchTo(oldcxt);
1121
1122 table_close(relation, AccessShareLock);
1123
1124 CACHE_elog(DEBUG2, "CatalogCacheInitializeCache: %s, %d keys",
1125 cache->cc_relname, cache->cc_nkeys);
1126
1127 /*
1128 * initialize cache's key information
1129 */
1130 for (i = 0; i < cache->cc_nkeys; ++i)
1131 {
1132 Oid keytype;
1133 RegProcedure eqfunc;
1134
1135 CatalogCacheInitializeCache_DEBUG2;
1136
1137 if (cache->cc_keyno[i] > 0)
1138 {
1139 Form_pg_attribute attr = TupleDescAttr(tupdesc,
1140 cache->cc_keyno[i] - 1);
1141
1142 keytype = attr->atttypid;
1143 /* cache key columns should always be NOT NULL */
1144 Assert(attr->attnotnull);
1145 }
1146 else
1147 {
1148 if (cache->cc_keyno[i] < 0)
1149 elog(FATAL, "sys attributes are not supported in caches");
1150 keytype = OIDOID;
1151 }
1152
1153 GetCCHashEqFuncs(keytype,
1154 &cache->cc_hashfunc[i],
1155 &eqfunc,
1156 &cache->cc_fastequal[i]);
1157
1158 /*
1159 * Do equality-function lookup (we assume this won't need a catalog
1160 * lookup for any supported type)
1161 */
1162 fmgr_info_cxt(eqfunc,
1163 &cache->cc_skey[i].sk_func,
1164 CacheMemoryContext);
1165
1166 /* Initialize sk_attno suitably for HeapKeyTest() and heap scans */
1167 cache->cc_skey[i].sk_attno = cache->cc_keyno[i];
1168
1169 /* Fill in sk_strategy as well --- always standard equality */
1170 cache->cc_skey[i].sk_strategy = BTEqualStrategyNumber;
1171 cache->cc_skey[i].sk_subtype = InvalidOid;
1172 /* If a catcache key requires a collation, it must be C collation */
1173 cache->cc_skey[i].sk_collation = C_COLLATION_OID;
1174
1175 CACHE_elog(DEBUG2, "CatalogCacheInitializeCache %s %d %p",
1176 cache->cc_relname, i, cache);
1177 }
1178
1179 /*
1180 * mark this cache fully initialized
1181 */
1182 cache->cc_tupdesc = tupdesc;
1183 }
1184
1185 /*
1186 * InitCatCachePhase2 -- external interface for CatalogCacheInitializeCache
1187 *
1188 * One reason to call this routine is to ensure that the relcache has
1189 * created entries for all the catalogs and indexes referenced by catcaches.
1190 * Therefore, provide an option to open the index as well as fixing the
1191 * cache itself. An exception is the indexes on pg_am, which we don't use
1192 * (cf. IndexScanOK).
1193 */
1194 void
1195 InitCatCachePhase2(CatCache *cache, bool touch_index)
1196 {
1197 if (cache->cc_tupdesc == NULL)
1198 CatalogCacheInitializeCache(cache);
1199
1200 if (touch_index &&
1201 cache->id != AMOID &&
1202 cache->id != AMNAME)
1203 {
1204 Relation idesc;
1205
1206 /*
1207 * We must lock the underlying catalog before opening the index to
1208 * avoid deadlock, since index_open could possibly result in reading
1209 * this same catalog, and if anyone else is exclusive-locking this
1210 * catalog and index they'll be doing it in that order.
1211 */
1212 LockRelationOid(cache->cc_reloid, AccessShareLock);
1213 idesc = index_open(cache->cc_indexoid, AccessShareLock);
1214
1215 /*
1216 * While we've got the index open, let's check that it's unique (and
1217 * not just deferrable-unique, thank you very much). This is just to
1218 * catch thinkos in definitions of new catcaches, so we don't worry
1219 * about the pg_am indexes not getting tested.
1220 */
1221 Assert(idesc->rd_index->indisunique &&
1222 idesc->rd_index->indimmediate);
1223
1224 index_close(idesc, AccessShareLock);
1225 UnlockRelationOid(cache->cc_reloid, AccessShareLock);
1226 }
1227 }
1228
1229
1230 /*
1231 * IndexScanOK
1232 *
1233 * This function checks for tuples that will be fetched by
1234 * IndexSupportInitialize() during relcache initialization for
1235 * certain system indexes that support critical syscaches.
1236 * We can't use an indexscan to fetch these, else we'll get into
1237 * infinite recursion. A plain heap scan will work, however.
1238 * Once we have completed relcache initialization (signaled by
1239 * criticalRelcachesBuilt), we don't have to worry anymore.
1240 *
1241 * Similarly, during backend startup we have to be able to use the
1242 * pg_authid, pg_auth_members and pg_database syscaches for
1243 * authentication even if we don't yet have relcache entries for those
1244 * catalogs' indexes.
1245 */
1246 static bool
1247 IndexScanOK(CatCache *cache)
1248 {
1249 switch (cache->id)
1250 {
1251 case INDEXRELID:
1252
1253 /*
1254 * Rather than tracking exactly which indexes have to be loaded
1255 * before we can use indexscans (which changes from time to time),
1256 * just force all pg_index searches to be heap scans until we've
1257 * built the critical relcaches.
1258 */
1259 if (!criticalRelcachesBuilt)
1260 return false;
1261 break;
1262
1263 case AMOID:
1264 case AMNAME:
1265
1266 /*
1267 * Always do heap scans in pg_am, because it's so small there's
1268 * not much point in an indexscan anyway. We *must* do this when
1269 * initially building critical relcache entries, but we might as
1270 * well just always do it.
1271 */
1272 return false;
1273
1274 case AUTHNAME:
1275 case AUTHOID:
1276 case AUTHMEMMEMROLE:
1277 case DATABASEOID:
1278
1279 /*
1280 * Protect authentication lookups occurring before relcache has
1281 * collected entries for shared indexes.
1282 */
1283 if (!criticalSharedRelcachesBuilt)
1284 return false;
1285 break;
1286
1287 default:
1288 break;
1289 }
1290
1291 /* Normal case, allow index scan */
1292 return true;
1293 }
1294
1295 /*
1296 * SearchCatCache
1297 *
1298 * This call searches a system cache for a tuple, opening the relation
1299 * if necessary (on the first access to a particular cache).
1300 *
1301 * The result is NULL if not found, or a pointer to a HeapTuple in
1302 * the cache. The caller must not modify the tuple, and must call
1303 * ReleaseCatCache() when done with it.
1304 *
1305 * The search key values should be expressed as Datums of the key columns'
1306 * datatype(s). (Pass zeroes for any unused parameters.) As a special
1307 * exception, the passed-in key for a NAME column can be just a C string;
1308 * the caller need not go to the trouble of converting it to a fully
1309 * null-padded NAME.
1310 */
1311 HeapTuple
1312 SearchCatCache(CatCache *cache,
1313 Datum v1,
1314 Datum v2,
1315 Datum v3,
1316 Datum v4)
1317 {
1318 return SearchCatCacheInternal(cache, cache->cc_nkeys, v1, v2, v3, v4);
1319 }
1320
1321
1322 /*
1323 * SearchCatCacheN() are SearchCatCache() versions for a specific number of
1324 * arguments. The compiler can inline the body and unroll loops, making them a
1325 * bit faster than SearchCatCache().
1326 */
1327
1328 HeapTuple
1329 SearchCatCache1(CatCache *cache,
1330 Datum v1)
1331 {
1332 return SearchCatCacheInternal(cache, 1, v1, 0, 0, 0);
1333 }
1334
1335
1336 HeapTuple
1337 SearchCatCache2(CatCache *cache,
1338 Datum v1, Datum v2)
1339 {
1340 return SearchCatCacheInternal(cache, 2, v1, v2, 0, 0);
1341 }
1342
1343
1344 HeapTuple
1345 SearchCatCache3(CatCache *cache,
1346 Datum v1, Datum v2, Datum v3)
1347 {
1348 return SearchCatCacheInternal(cache, 3, v1, v2, v3, 0);
1349 }
1350
1351
1352 HeapTuple
1353 SearchCatCache4(CatCache *cache,
1354 Datum v1, Datum v2, Datum v3, Datum v4)
1355 {
1356 return SearchCatCacheInternal(cache, 4, v1, v2, v3, v4);
1357 }
1358
1359 /*
1360 * Work-horse for SearchCatCache/SearchCatCacheN.
1361 */
1362 static inline HeapTuple
1363 SearchCatCacheInternal(CatCache *cache,
1364 int nkeys,
1365 Datum v1,
1366 Datum v2,
1367 Datum v3,
1368 Datum v4)
1369 {
1370 Datum arguments[CATCACHE_MAXKEYS];
1371 uint32 hashValue;
1372 Index hashIndex;
1373 dlist_iter iter;
1374 dlist_head *bucket;
1375 CatCTup *ct;
1376
1377 /* Make sure we're in an xact, even if this ends up being a cache hit */
1378 Assert(IsTransactionState());
1379
1380 Assert(cache->cc_nkeys == nkeys);
1381
1382 /*
1383 * one-time startup overhead for each cache
1384 */
1385 if (unlikely(cache->cc_tupdesc == NULL))
1386 CatalogCacheInitializeCache(cache);
1387
1388 #ifdef CATCACHE_STATS
1389 cache->cc_searches++;
1390 #endif
1391
1392 /* Initialize local parameter array */
1393 arguments[0] = v1;
1394 arguments[1] = v2;
1395 arguments[2] = v3;
1396 arguments[3] = v4;
1397
1398 /*
1399 * find the hash bucket in which to look for the tuple
1400 */
1401 hashValue = CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4);
1402 hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets);
1403
1404 /*
1405 * scan the hash bucket until we find a match or exhaust our tuples
1406 *
1407 * Note: it's okay to use dlist_foreach here, even though we modify the
1408 * dlist within the loop, because we don't continue the loop afterwards.
1409 */
1410 bucket = &cache->cc_bucket[hashIndex];
1411 dlist_foreach(iter, bucket)
1412 {
1413 ct = dlist_container(CatCTup, cache_elem, iter.cur);
1414
1415 if (ct->dead)
1416 continue; /* ignore dead entries */
1417
1418 if (ct->hash_value != hashValue)
1419 continue; /* quickly skip entry if wrong hash val */
1420
1421 if (!CatalogCacheCompareTuple(cache, nkeys, ct->keys, arguments))
1422 continue;
1423
1424 /*
1425 * We found a match in the cache. Move it to the front of the list
1426 * for its hashbucket, in order to speed subsequent searches. (The
1427 * most frequently accessed elements in any hashbucket will tend to be
1428 * near the front of the hashbucket's list.)
1429 */
1430 dlist_move_head(bucket, &ct->cache_elem);
1431
1432 /*
1433 * If it's a positive entry, bump its refcount and return it. If it's
1434 * negative, we can report failure to the caller.
1435 */
1436 if (!ct->negative)
1437 {
1438 ResourceOwnerEnlarge(CurrentResourceOwner);
1439 ct->refcount++;
1440 ResourceOwnerRememberCatCacheRef(CurrentResourceOwner, &ct->tuple);
1441
1442 CACHE_elog(DEBUG2, "SearchCatCache(%s): found in bucket %d",
1443 cache->cc_relname, hashIndex);
1444
1445 #ifdef CATCACHE_STATS
1446 cache->cc_hits++;
1447 #endif
1448
1449 return &ct->tuple;
1450 }
1451 else
1452 {
1453 CACHE_elog(DEBUG2, "SearchCatCache(%s): found neg entry in bucket %d",
1454 cache->cc_relname, hashIndex);
1455
1456 #ifdef CATCACHE_STATS
1457 cache->cc_neg_hits++;
1458 #endif
1459
1460 return NULL;
1461 }
1462 }
1463
1464 return SearchCatCacheMiss(cache, nkeys, hashValue, hashIndex, v1, v2, v3, v4);
1465 }
1466
1467 /*
1468 * Search the actual catalogs, rather than the cache.
1469 *
1470 * This is kept separate from SearchCatCacheInternal() to keep the fast-path
1471 * as small as possible. To avoid that effort being undone by a helpful
1472 * compiler, try to explicitly forbid inlining.
1473 */
1474 static pg_noinline HeapTuple
1475 SearchCatCacheMiss(CatCache *cache,
1476 int nkeys,
1477 uint32 hashValue,
1478 Index hashIndex,
1479 Datum v1,
1480 Datum v2,
1481 Datum v3,
1482 Datum v4)
1483 {
1484 ScanKeyData cur_skey[CATCACHE_MAXKEYS];
1485 Relation relation;
1486 SysScanDesc scandesc;
1487 HeapTuple ntp;
1488 CatCTup *ct;
1489 bool stale;
1490 Datum arguments[CATCACHE_MAXKEYS];
1491
1492 /* Initialize local parameter array */
1493 arguments[0] = v1;
1494 arguments[1] = v2;
1495 arguments[2] = v3;
1496 arguments[3] = v4;
1497
1498 /*
1499 * Tuple was not found in cache, so we have to try to retrieve it directly
1500 * from the relation. If found, we will add it to the cache; if not
1501 * found, we will add a negative cache entry instead.
1502 *
1503 * NOTE: it is possible for recursive cache lookups to occur while reading
1504 * the relation --- for example, due to shared-cache-inval messages being
1505 * processed during table_open(). This is OK. It's even possible for one
1506 * of those lookups to find and enter the very same tuple we are trying to
1507 * fetch here. If that happens, we will enter a second copy of the tuple
1508 * into the cache. The first copy will never be referenced again, and
1509 * will eventually age out of the cache, so there's no functional problem.
1510 * This case is rare enough that it's not worth expending extra cycles to
1511 * detect.
1512 *
1513 * Another case, which we *must* handle, is that the tuple could become
1514 * outdated during CatalogCacheCreateEntry's attempt to detoast it (since
1515 * AcceptInvalidationMessages can run during TOAST table access). We do
1516 * not want to return already-stale catcache entries, so we loop around
1517 * and do the table scan again if that happens.
1518 */
1519 relation = table_open(cache->cc_reloid, AccessShareLock);
1520
1521 /*
1522 * Ok, need to make a lookup in the relation, copy the scankey and fill
1523 * out any per-call fields.
1524 */
1525 memcpy(cur_skey, cache->cc_skey, sizeof(ScanKeyData) * nkeys);
1526 cur_skey[0].sk_argument = v1;
1527 cur_skey[1].sk_argument = v2;
1528 cur_skey[2].sk_argument = v3;
1529 cur_skey[3].sk_argument = v4;
1530
1531 do
1532 {
1533 scandesc = systable_beginscan(relation,
1534 cache->cc_indexoid,
1535 IndexScanOK(cache),
1536 NULL,
1537 nkeys,
1538 cur_skey);
1539
1540 ct = NULL;
1541 stale = false;
1542
1543 while (HeapTupleIsValid(ntp = systable_getnext(scandesc)))
1544 {
1545 ct = CatalogCacheCreateEntry(cache, ntp, NULL,
1546 hashValue, hashIndex);
1547 /* upon failure, we must start the scan over */
1548 if (ct == NULL)
1549 {
1550 stale = true;
1551 break;
1552 }
1553 /* immediately set the refcount to 1 */
1554 ResourceOwnerEnlarge(CurrentResourceOwner);
1555 ct->refcount++;
1556 ResourceOwnerRememberCatCacheRef(CurrentResourceOwner, &ct->tuple);
1557 break; /* assume only one match */
1558 }
1559
1560 systable_endscan(scandesc);
1561 } while (stale);
1562
1563 table_close(relation, AccessShareLock);
1564
1565 /*
1566 * If tuple was not found, we need to build a negative cache entry
1567 * containing a fake tuple. The fake tuple has the correct key columns,
1568 * but nulls everywhere else.
1569 *
1570 * In bootstrap mode, we don't build negative entries, because the cache
1571 * invalidation mechanism isn't alive and can't clear them if the tuple
1572 * gets created later. (Bootstrap doesn't do UPDATEs, so it doesn't need
1573 * cache inval for that.)
1574 */
1575 if (ct == NULL)
1576 {
1577 if (IsBootstrapProcessingMode())
1578 return NULL;
1579
1580 ct = CatalogCacheCreateEntry(cache, NULL, arguments,
1581 hashValue, hashIndex);
1582
1583 /* Creating a negative cache entry shouldn't fail */
1584 Assert(ct != NULL);
1585
1586 CACHE_elog(DEBUG2, "SearchCatCache(%s): Contains %d/%d tuples",
1587 cache->cc_relname, cache->cc_ntup, CacheHdr->ch_ntup);
1588 CACHE_elog(DEBUG2, "SearchCatCache(%s): put neg entry in bucket %d",
1589 cache->cc_relname, hashIndex);
1590
1591 /*
1592 * We are not returning the negative entry to the caller, so leave its
1593 * refcount zero.
1594 */
1595
1596 return NULL;
1597 }
1598
1599 CACHE_elog(DEBUG2, "SearchCatCache(%s): Contains %d/%d tuples",
1600 cache->cc_relname, cache->cc_ntup, CacheHdr->ch_ntup);
1601 CACHE_elog(DEBUG2, "SearchCatCache(%s): put in bucket %d",
1602 cache->cc_relname, hashIndex);
1603
1604 #ifdef CATCACHE_STATS
1605 cache->cc_newloads++;
1606 #endif
1607
1608 return &ct->tuple;
1609 }
1610
1611 /*
1612 * ReleaseCatCache
1613 *
1614 * Decrement the reference count of a catcache entry (releasing the
1615 * hold grabbed by a successful SearchCatCache).
1616 *
1617 * NOTE: if compiled with -DCATCACHE_FORCE_RELEASE then catcache entries
1618 * will be freed as soon as their refcount goes to zero. In combination
1619 * with aset.c's CLOBBER_FREED_MEMORY option, this provides a good test
1620 * to catch references to already-released catcache entries.
1621 */
1622 void
1623 ReleaseCatCache(HeapTuple tuple)
1624 {
1625 ReleaseCatCacheWithOwner(tuple, CurrentResourceOwner);
1626 }
1627
1628 static void
1629 ReleaseCatCacheWithOwner(HeapTuple tuple, ResourceOwner resowner)
1630 {
1631 CatCTup *ct = (CatCTup *) (((char *) tuple) -
1632 offsetof(CatCTup, tuple));
1633
1634 /* Safety checks to ensure we were handed a cache entry */
1635 Assert(ct->ct_magic == CT_MAGIC);
1636 Assert(ct->refcount > 0);
1637
1638 ct->refcount--;
1639 if (resowner)
1640 ResourceOwnerForgetCatCacheRef(CurrentResourceOwner, &ct->tuple);
1641
1642 if (
1643 #ifndef CATCACHE_FORCE_RELEASE
1644 ct->dead &&
1645 #endif
1646 ct->refcount == 0 &&
1647 (ct->c_list == NULL || ct->c_list->refcount == 0))
1648 CatCacheRemoveCTup(ct->my_cache, ct);
1649 }
1650
1651
1652 /*
1653 * GetCatCacheHashValue
1654 *
1655 * Compute the hash value for a given set of search keys.
1656 *
1657 * The reason for exposing this as part of the API is that the hash value is
1658 * exposed in cache invalidation operations, so there are places outside the
1659 * catcache code that need to be able to compute the hash values.
1660 */
1661 uint32
1662 GetCatCacheHashValue(CatCache *cache,
1663 Datum v1,
1664 Datum v2,
1665 Datum v3,
1666 Datum v4)
1667 {
1668 /*
1669 * one-time startup overhead for each cache
1670 */
1671 if (cache->cc_tupdesc == NULL)
1672 CatalogCacheInitializeCache(cache);
1673
1674 /*
1675 * calculate the hash value
1676 */
1677 return CatalogCacheComputeHashValue(cache, cache->cc_nkeys, v1, v2, v3, v4);
1678 }
1679
1680
1681 /*
1682 * SearchCatCacheList
1683 *
1684 * Generate a list of all tuples matching a partial key (that is,
1685 * a key specifying just the first K of the cache's N key columns).
1686 *
1687 * It doesn't make any sense to specify all of the cache's key columns
1688 * here: since the key is unique, there could be at most one match, so
1689 * you ought to use SearchCatCache() instead. Hence this function takes
1690 * one fewer Datum argument than SearchCatCache() does.
1691 *
1692 * The caller must not modify the list object or the pointed-to tuples,
1693 * and must call ReleaseCatCacheList() when done with the list.
1694 */
1695 CatCList *
1696 SearchCatCacheList(CatCache *cache,
1697 int nkeys,
1698 Datum v1,
1699 Datum v2,
1700 Datum v3)
1701 {
1702 Datum v4 = 0; /* dummy last-column value */
1703 Datum arguments[CATCACHE_MAXKEYS];
1704 uint32 lHashValue;
1705 Index lHashIndex;
1706 dlist_iter iter;
1707 dlist_head *lbucket;
1708 CatCList *cl;
1709 CatCTup *ct;
1710 List *volatile ctlist;
1711 ListCell *ctlist_item;
1712 int nmembers;
1713 bool ordered;
1714 HeapTuple ntp;
1715 MemoryContext oldcxt;
1716 int i;
1717 CatCInProgress *save_in_progress;
1718 CatCInProgress in_progress_ent;
1719
1720 /*
1721 * one-time startup overhead for each cache
1722 */
1723 if (unlikely(cache->cc_tupdesc == NULL))
1724 CatalogCacheInitializeCache(cache);
1725
1726 Assert(nkeys > 0 && nkeys < cache->cc_nkeys);
1727
1728 #ifdef CATCACHE_STATS
1729 cache->cc_lsearches++;
1730 #endif
1731
1732 /* Initialize local parameter array */
1733 arguments[0] = v1;
1734 arguments[1] = v2;
1735 arguments[2] = v3;
1736 arguments[3] = v4;
1737
1738 /*
1739 * If we haven't previously done a list search in this cache, create the
1740 * bucket header array; otherwise, consider whether it's time to enlarge
1741 * it.
1742 */
1743 if (cache->cc_lbucket == NULL)
1744 {
1745 /* Arbitrary initial size --- must be a power of 2 */
1746 int nbuckets = 16;
1747
1748 cache->cc_lbucket = (dlist_head *)
1749 MemoryContextAllocZero(CacheMemoryContext,
1750 nbuckets * sizeof(dlist_head));
1751 /* Don't set cc_nlbuckets if we get OOM allocating cc_lbucket */
1752 cache->cc_nlbuckets = nbuckets;
1753 }
1754 else
1755 {
1756 /*
1757 * If the hash table has become too full, enlarge the buckets array.
1758 * Quite arbitrarily, we enlarge when fill factor > 2.
1759 */
1760 if (cache->cc_nlist > cache->cc_nlbuckets * 2)
1761 RehashCatCacheLists(cache);
1762 }
1763
1764 /*
1765 * Find the hash bucket in which to look for the CatCList.
1766 */
1767 lHashValue = CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4);
1768 lHashIndex = HASH_INDEX(lHashValue, cache->cc_nlbuckets);
1769
1770 /*
1771 * scan the items until we find a match or exhaust our list
1772 *
1773 * Note: it's okay to use dlist_foreach here, even though we modify the
1774 * dlist within the loop, because we don't continue the loop afterwards.
1775 */
1776 lbucket = &cache->cc_lbucket[lHashIndex];
1777 dlist_foreach(iter, lbucket)
1778 {
1779 cl = dlist_container(CatCList, cache_elem, iter.cur);
1780
1781 if (cl->dead)
1782 continue; /* ignore dead entries */
1783
1784 if (cl->hash_value != lHashValue)
1785 continue; /* quickly skip entry if wrong hash val */
1786
1787 /*
1788 * see if the cached list matches our key.
1789 */
1790 if (cl->nkeys != nkeys)
1791 continue;
1792
1793 if (!CatalogCacheCompareTuple(cache, nkeys, cl->keys, arguments))
1794 continue;
1795
1796 /*
1797 * We found a matching list. Move the list to the front of the list
1798 * for its hashbucket, so as to speed subsequent searches. (We do not
1799 * move the members to the fronts of their hashbucket lists, however,
1800 * since there's no point in that unless they are searched for
1801 * individually.)
1802 */
1803 dlist_move_head(lbucket, &cl->cache_elem);
1804
1805 /* Bump the list's refcount and return it */
1806 ResourceOwnerEnlarge(CurrentResourceOwner);
1807 cl->refcount++;
1808 ResourceOwnerRememberCatCacheListRef(CurrentResourceOwner, cl);
1809
1810 CACHE_elog(DEBUG2, "SearchCatCacheList(%s): found list",
1811 cache->cc_relname);
1812
1813 #ifdef CATCACHE_STATS
1814 cache->cc_lhits++;
1815 #endif
1816
1817 return cl;
1818 }
1819
1820 /*
1821 * List was not found in cache, so we have to build it by reading the
1822 * relation. For each matching tuple found in the relation, use an
1823 * existing cache entry if possible, else build a new one.
1824 *
1825 * We have to bump the member refcounts temporarily to ensure they won't
1826 * get dropped from the cache while loading other members. We use a PG_TRY
1827 * block to ensure we can undo those refcounts if we get an error before
1828 * we finish constructing the CatCList. ctlist must be valid throughout
1829 * the PG_TRY block.
1830 */
1831 ctlist = NIL;
1832
1833 /*
1834 * Cache invalidation can happen while we're building the list.
1835 * CatalogCacheCreateEntry() handles concurrent invalidation of individual
1836 * tuples, but it's also possible that a new entry is concurrently added
1837 * that should be part of the list we're building. Register an
1838 * "in-progress" entry that will receive the invalidation, until we have
1839 * built the final list entry.
1840 */
1841 save_in_progress = catcache_in_progress_stack;
1842 in_progress_ent.next = catcache_in_progress_stack;
1843 in_progress_ent.cache = cache;
1844 in_progress_ent.hash_value = lHashValue;
1845 in_progress_ent.list = true;
1846 in_progress_ent.dead = false;
1847 catcache_in_progress_stack = &in_progress_ent;
1848
1849 PG_TRY();
1850 {
1851 ScanKeyData cur_skey[CATCACHE_MAXKEYS];
1852 Relation relation;
1853 SysScanDesc scandesc;
1854 bool first_iter = true;
1855
1856 relation = table_open(cache->cc_reloid, AccessShareLock);
1857
1858 /*
1859 * Ok, need to make a lookup in the relation, copy the scankey and
1860 * fill out any per-call fields.
1861 */
1862 memcpy(cur_skey, cache->cc_skey, sizeof(ScanKeyData) * cache->cc_nkeys);
1863 cur_skey[0].sk_argument = v1;
1864 cur_skey[1].sk_argument = v2;
1865 cur_skey[2].sk_argument = v3;
1866 cur_skey[3].sk_argument = v4;
1867
1868 /*
1869 * Scan the table for matching entries. If an invalidation arrives
1870 * mid-build, we will loop back here to retry.
1871 */
1872 do
1873 {
1874 /*
1875 * If we are retrying, release refcounts on any items created on
1876 * the previous iteration. We dare not try to free them if
1877 * they're now unreferenced, since an error while doing that would
1878 * result in the PG_CATCH below doing extra refcount decrements.
1879 * Besides, we'll likely re-adopt those items in the next
1880 * iteration, so it's not worth complicating matters to try to get
1881 * rid of them.
1882 */
1883 foreach(ctlist_item, ctlist)
1884 {
1885 ct = (CatCTup *) lfirst(ctlist_item);
1886 Assert(ct->c_list == NULL);
1887 Assert(ct->refcount > 0);
1888 ct->refcount--;
1889 }
1890 /* Reset ctlist in preparation for new try */
1891 ctlist = NIL;
1892 in_progress_ent.dead = false;
1893
1894 scandesc = systable_beginscan(relation,
1895 cache->cc_indexoid,
1896 IndexScanOK(cache),
1897 NULL,
1898 nkeys,
1899 cur_skey);
1900
1901 /* The list will be ordered iff we are doing an index scan */
1902 ordered = (scandesc->irel != NULL);
1903
1904 /* Injection point to help testing the recursive invalidation case */
1905 if (first_iter)
1906 {
1907 INJECTION_POINT("catcache-list-miss-systable-scan-started");
1908 first_iter = false;
1909 }
1910
1911 while (HeapTupleIsValid(ntp = systable_getnext(scandesc)) &&
1912 !in_progress_ent.dead)
1913 {
1914 uint32 hashValue;
1915 Index hashIndex;
1916 bool found = false;
1917 dlist_head *bucket;
1918
1919 /*
1920 * See if there's an entry for this tuple already.
1921 */
1922 ct = NULL;
1923 hashValue = CatalogCacheComputeTupleHashValue(cache, cache->cc_nkeys, ntp);
1924 hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets);
1925
1926 bucket = &cache->cc_bucket[hashIndex];
1927 dlist_foreach(iter, bucket)
1928 {
1929 ct = dlist_container(CatCTup, cache_elem, iter.cur);
1930
1931 if (ct->dead || ct->negative)
1932 continue; /* ignore dead and negative entries */
1933
1934 if (ct->hash_value != hashValue)
1935 continue; /* quickly skip entry if wrong hash val */
1936
1937 if (!ItemPointerEquals(&(ct->tuple.t_self), &(ntp->t_self)))
1938 continue; /* not same tuple */
1939
1940 /*
1941 * Found a match, but can't use it if it belongs to
1942 * another list already
1943 */
1944 if (ct->c_list)
1945 continue;
1946
1947 found = true;
1948 break; /* A-OK */
1949 }
1950
1951 if (!found)
1952 {
1953 /* We didn't find a usable entry, so make a new one */
1954 ct = CatalogCacheCreateEntry(cache, ntp, NULL,
1955 hashValue, hashIndex);
1956
1957 /* upon failure, we must start the scan over */
1958 if (ct == NULL)
1959 {
1960 in_progress_ent.dead = true;
1961 break;
1962 }
1963 }
1964
1965 /* Careful here: add entry to ctlist, then bump its refcount */
1966 /* This way leaves state correct if lappend runs out of memory */
1967 ctlist = lappend(ctlist, ct);
1968 ct->refcount++;
1969 }
1970
1971 systable_endscan(scandesc);
1972 } while (in_progress_ent.dead);
1973
1974 table_close(relation, AccessShareLock);
1975
1976 /* Make sure the resource owner has room to remember this entry. */
1977 ResourceOwnerEnlarge(CurrentResourceOwner);
1978
1979 /* Now we can build the CatCList entry. */
1980 oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
1981 nmembers = list_length(ctlist);
1982 cl = (CatCList *)
1983 palloc(offsetof(CatCList, members) + nmembers * sizeof(CatCTup *));
1984
1985 /* Extract key values */
1986 CatCacheCopyKeys(cache->cc_tupdesc, nkeys, cache->cc_keyno,
1987 arguments, cl->keys);
1988 MemoryContextSwitchTo(oldcxt);
1989
1990 /*
1991 * We are now past the last thing that could trigger an elog before we
1992 * have finished building the CatCList and remembering it in the
1993 * resource owner. So it's OK to fall out of the PG_TRY, and indeed
1994 * we'd better do so before we start marking the members as belonging
1995 * to the list.
1996 */
1997 }
1998 PG_CATCH();
1999 {
2000 Assert(catcache_in_progress_stack == &in_progress_ent);
2001 catcache_in_progress_stack = save_in_progress;
2002
2003 foreach(ctlist_item, ctlist)
2004 {
2005 ct = (CatCTup *) lfirst(ctlist_item);
2006 Assert(ct->c_list == NULL);
2007 Assert(ct->refcount > 0);
2008 ct->refcount--;
2009 if (
2010 #ifndef CATCACHE_FORCE_RELEASE
2011 ct->dead &&
2012 #endif
2013 ct->refcount == 0 &&
2014 (ct->c_list == NULL || ct->c_list->refcount == 0))
2015 CatCacheRemoveCTup(cache, ct);
2016 }
2017
2018 PG_RE_THROW();
2019 }
2020 PG_END_TRY();
2021 Assert(catcache_in_progress_stack == &in_progress_ent);
2022 catcache_in_progress_stack = save_in_progress;
2023
2024 cl->cl_magic = CL_MAGIC;
2025 cl->my_cache = cache;
2026 cl->refcount = 0; /* for the moment */
2027 cl->dead = false;
2028 cl->ordered = ordered;
2029 cl->nkeys = nkeys;
2030 cl->hash_value = lHashValue;
2031 cl->n_members = nmembers;
2032
2033 i = 0;
2034 foreach(ctlist_item, ctlist)
2035 {
2036 cl->members[i++] = ct = (CatCTup *) lfirst(ctlist_item);
2037 Assert(ct->c_list == NULL);
2038 ct->c_list = cl;
2039 /* release the temporary refcount on the member */
2040 Assert(ct->refcount > 0);
2041 ct->refcount--;
2042 /* mark list dead if any members already dead */
2043 if (ct->dead)
2044 cl->dead = true;
2045 }
2046 Assert(i == nmembers);
2047
2048 /*
2049 * Add the CatCList to the appropriate bucket, and count it.
2050 */
2051 dlist_push_head(lbucket, &cl->cache_elem);
2052
2053 cache->cc_nlist++;
2054
2055 /* Finally, bump the list's refcount and return it */
2056 cl->refcount++;
2057 ResourceOwnerRememberCatCacheListRef(CurrentResourceOwner, cl);
2058
2059 CACHE_elog(DEBUG2, "SearchCatCacheList(%s): made list of %d members",
2060 cache->cc_relname, nmembers);
2061
2062 return cl;
2063 }
2064
2065 /*
2066 * ReleaseCatCacheList
2067 *
2068 * Decrement the reference count of a catcache list.
2069 */
2070 void
2071 ReleaseCatCacheList(CatCList *list)
2072 {
2073 ReleaseCatCacheListWithOwner(list, CurrentResourceOwner);
2074 }
2075
2076 static void
2077 ReleaseCatCacheListWithOwner(CatCList *list, ResourceOwner resowner)
2078 {
2079 /* Safety checks to ensure we were handed a cache entry */
2080 Assert(list->cl_magic == CL_MAGIC);
2081 Assert(list->refcount > 0);
2082 list->refcount--;
2083 if (resowner)
2084 ResourceOwnerForgetCatCacheListRef(CurrentResourceOwner, list);
2085
2086 if (
2087 #ifndef CATCACHE_FORCE_RELEASE
2088 list->dead &&
2089 #endif
2090 list->refcount == 0)
2091 CatCacheRemoveCList(list->my_cache, list);
2092 }
2093
2094
2095 /*
2096 * CatalogCacheCreateEntry
2097 * Create a new CatCTup entry, copying the given HeapTuple and other
2098 * supplied data into it. The new entry initially has refcount 0.
2099 *
2100 * To create a normal cache entry, ntp must be the HeapTuple just fetched
2101 * from scandesc, and "arguments" is not used. To create a negative cache
2102 * entry, pass NULL for ntp; then "arguments" is the cache keys to use.
2103 * In either case, hashValue/hashIndex are the hash values computed from
2104 * the cache keys.
2105 *
2106 * Returns NULL if we attempt to detoast the tuple and observe that it
2107 * became stale. (This cannot happen for a negative entry.) Caller must
2108 * retry the tuple lookup in that case.
2109 */
2110 static CatCTup *
2111 CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments,
2112 uint32 hashValue, Index hashIndex)
2113 {
2114 CatCTup *ct;
2115 MemoryContext oldcxt;
2116
2117 if (ntp)
2118 {
2119 int i;
2120 HeapTuple dtp = NULL;
2121
2122 /*
2123 * The invalidation of the in-progress entry essentially never happens
2124 * during our regression tests, and there's no easy way to force it to
2125 * fail for testing purposes. To ensure we have test coverage for the
2126 * retry paths in our callers, make debug builds randomly fail about
2127 * 0.1% of the times through this code path, even when there's no
2128 * toasted fields.
2129 */
2130 #ifdef USE_ASSERT_CHECKING
2131 if (pg_prng_uint32(&pg_global_prng_state) <= (PG_UINT32_MAX / 1000))
2132 return NULL;
2133 #endif
2134
2135 /*
2136 * If there are any out-of-line toasted fields in the tuple, expand
2137 * them in-line. This saves cycles during later use of the catcache
2138 * entry, and also protects us against the possibility of the toast
2139 * tuples being freed before we attempt to fetch them, in case of
2140 * something using a slightly stale catcache entry.
2141 */
2142 if (HeapTupleHasExternal(ntp))
2143 {
2144 CatCInProgress *save_in_progress;
2145 CatCInProgress in_progress_ent;
2146
2147 /*
2148 * The tuple could become stale while we are doing toast table
2149 * access (since AcceptInvalidationMessages can run then). The
2150 * invalidation will mark our in-progress entry as dead.
2151 */
2152 save_in_progress = catcache_in_progress_stack;
2153 in_progress_ent.next = catcache_in_progress_stack;
2154 in_progress_ent.cache = cache;
2155 in_progress_ent.hash_value = hashValue;
2156 in_progress_ent.list = false;
2157 in_progress_ent.dead = false;
2158 catcache_in_progress_stack = &in_progress_ent;
2159
2160 PG_TRY();
2161 {
2162 dtp = toast_flatten_tuple(ntp, cache->cc_tupdesc);
2163 }
2164 PG_FINALLY();
2165 {
2166 Assert(catcache_in_progress_stack == &in_progress_ent);
2167 catcache_in_progress_stack = save_in_progress;
2168 }
2169 PG_END_TRY();
2170
2171 if (in_progress_ent.dead)
2172 {
2173 heap_freetuple(dtp);
2174 return NULL;
2175 }
2176 }
2177 else
2178 dtp = ntp;
2179
2180 /* Allocate memory for CatCTup and the cached tuple in one go */
2181 oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
2182
2183 ct = (CatCTup *) palloc(sizeof(CatCTup) +
2184 MAXIMUM_ALIGNOF + dtp->t_len);
2185 ct->tuple.t_len = dtp->t_len;
2186 ct->tuple.t_self = dtp->t_self;
2187 ct->tuple.t_tableOid = dtp->t_tableOid;
2188 ct->tuple.t_data = (HeapTupleHeader)
2189 MAXALIGN(((char *) ct) + sizeof(CatCTup));
2190 /* copy tuple contents */
2191 memcpy((char *) ct->tuple.t_data,
2192 (const char *) dtp->t_data,
2193 dtp->t_len);
2194 MemoryContextSwitchTo(oldcxt);
2195
2196 if (dtp != ntp)
2197 heap_freetuple(dtp);
2198
2199 /* extract keys - they'll point into the tuple if not by-value */
2200 for (i = 0; i < cache->cc_nkeys; i++)
2201 {
2202 Datum atp;
2203 bool isnull;
2204
2205 atp = heap_getattr(&ct->tuple,
2206 cache->cc_keyno[i],
2207 cache->cc_tupdesc,
2208 &isnull);
2209 Assert(!isnull);
2210 ct->keys[i] = atp;
2211 }
2212 }
2213 else
2214 {
2215 /* Set up keys for a negative cache entry */
2216 oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
2217 ct = (CatCTup *) palloc(sizeof(CatCTup));
2218
2219 /*
2220 * Store keys - they'll point into separately allocated memory if not
2221 * by-value.
2222 */
2223 CatCacheCopyKeys(cache->cc_tupdesc, cache->cc_nkeys, cache->cc_keyno,
2224 arguments, ct->keys);
2225 MemoryContextSwitchTo(oldcxt);
2226 }
2227
2228 /*
2229 * Finish initializing the CatCTup header, and add it to the cache's
2230 * linked list and counts.
2231 */
2232 ct->ct_magic = CT_MAGIC;
2233 ct->my_cache = cache;
2234 ct->c_list = NULL;
2235 ct->refcount = 0; /* for the moment */
2236 ct->dead = false;
2237 ct->negative = (ntp == NULL);
2238 ct->hash_value = hashValue;
2239
2240 dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem);
2241
2242 cache->cc_ntup++;
2243 CacheHdr->ch_ntup++;
2244
2245 /*
2246 * If the hash table has become too full, enlarge the buckets array. Quite
2247 * arbitrarily, we enlarge when fill factor > 2.
2248 */
2249 if (cache->cc_ntup > cache->cc_nbuckets * 2)
2250 RehashCatCache(cache);
2251
2252 return ct;
2253 }
2254
2255 /*
2256 * Helper routine that frees keys stored in the keys array.
2257 */
2258 static void
2259 CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *keys)
2260 {
2261 int i;
2262
2263 for (i = 0; i < nkeys; i++)
2264 {
2265 int attnum = attnos[i];
2266 Form_pg_attribute att;
2267
2268 /* system attribute are not supported in caches */
2269 Assert(attnum > 0);
2270
2271 att = TupleDescAttr(tupdesc, attnum - 1);
2272
2273 if (!att->attbyval)
2274 pfree(DatumGetPointer(keys[i]));
2275 }
2276 }
2277
2278 /*
2279 * Helper routine that copies the keys in the srckeys array into the dstkeys
2280 * one, guaranteeing that the datums are fully allocated in the current memory
2281 * context.
2282 */
2283 static void
2284 CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos,
2285 Datum *srckeys, Datum *dstkeys)
2286 {
2287 int i;
2288
2289 /*
2290 * XXX: memory and lookup performance could possibly be improved by
2291 * storing all keys in one allocation.
2292 */
2293
2294 for (i = 0; i < nkeys; i++)
2295 {
2296 int attnum = attnos[i];
2297 Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
2298 Datum src = srckeys[i];
2299 NameData srcname;
2300
2301 /*
2302 * Must be careful in case the caller passed a C string where a NAME
2303 * is wanted: convert the given argument to a correctly padded NAME.
2304 * Otherwise the memcpy() done by datumCopy() could fall off the end
2305 * of memory.
2306 */
2307 if (att->atttypid == NAMEOID)
2308 {
2309 namestrcpy(&srcname, DatumGetCString(src));
2310 src = NameGetDatum(&srcname);
2311 }
2312
2313 dstkeys[i] = datumCopy(src,
2314 att->attbyval,
2315 att->attlen);
2316 }
2317 }
2318
2319 /*
2320 * PrepareToInvalidateCacheTuple()
2321 *
2322 * This is part of a rather subtle chain of events, so pay attention:
2323 *
2324 * When a tuple is inserted or deleted, it cannot be flushed from the
2325 * catcaches immediately, for reasons explained at the top of cache/inval.c.
2326 * Instead we have to add entry(s) for the tuple to a list of pending tuple
2327 * invalidations that will be done at the end of the command or transaction.
2328 *
2329 * The lists of tuples that need to be flushed are kept by inval.c. This
2330 * routine is a helper routine for inval.c. Given a tuple belonging to
2331 * the specified relation, find all catcaches it could be in, compute the
2332 * correct hash value for each such catcache, and call the specified
2333 * function to record the cache id and hash value in inval.c's lists.
2334 * SysCacheInvalidate will be called later, if appropriate,
2335 * using the recorded information.
2336 *
2337 * For an insert or delete, tuple is the target tuple and newtuple is NULL.
2338 * For an update, we are called just once, with tuple being the old tuple
2339 * version and newtuple the new version. We should make two list entries
2340 * if the tuple's hash value changed, but only one if it didn't.
2341 *
2342 * Note that it is irrelevant whether the given tuple is actually loaded
2343 * into the catcache at the moment. Even if it's not there now, it might
2344 * be by the end of the command, or there might be a matching negative entry
2345 * to flush --- or other backends' caches might have such entries --- so
2346 * we have to make list entries to flush it later.
2347 *
2348 * Also note that it's not an error if there are no catcaches for the
2349 * specified relation. inval.c doesn't know exactly which rels have
2350 * catcaches --- it will call this routine for any tuple that's in a
2351 * system relation.
2352 */
2353 void
2354 PrepareToInvalidateCacheTuple(Relation relation,
2355 HeapTuple tuple,
2356 HeapTuple newtuple,
2357 void (*function) (int, uint32, Oid, void *),
2358 void *context)
2359 {
2360 slist_iter iter;
2361 Oid reloid;
2362
2363 CACHE_elog(DEBUG2, "PrepareToInvalidateCacheTuple: called");
2364
2365 /*
2366 * sanity checks
2367 */
2368 Assert(RelationIsValid(relation));
2369 Assert(HeapTupleIsValid(tuple));
2370 Assert(PointerIsValid(function));
2371 Assert(CacheHdr != NULL);
2372
2373 reloid = RelationGetRelid(relation);
2374
2375 /* ----------------
2376 * for each cache
2377 * if the cache contains tuples from the specified relation
2378 * compute the tuple's hash value(s) in this cache,
2379 * and call the passed function to register the information.
2380 * ----------------
2381 */
2382
2383 slist_foreach(iter, &CacheHdr->ch_caches)
2384 {
2385 CatCache *ccp = slist_container(CatCache, cc_next, iter.cur);
2386 uint32 hashvalue;
2387 Oid dbid;
2388
2389 if (ccp->cc_reloid != reloid)
2390 continue;
2391
2392 /* Just in case cache hasn't finished initialization yet... */
2393 if (ccp->cc_tupdesc == NULL)
2394 CatalogCacheInitializeCache(ccp);
2395
2396 hashvalue = CatalogCacheComputeTupleHashValue(ccp, ccp->cc_nkeys, tuple);
2397 dbid = ccp->cc_relisshared ? (Oid) 0 : MyDatabaseId;
2398
2399 (*function) (ccp->id, hashvalue, dbid, context);
2400
2401 if (newtuple)
2402 {
2403 uint32 newhashvalue;
2404
2405 newhashvalue = CatalogCacheComputeTupleHashValue(ccp, ccp->cc_nkeys, newtuple);
2406
2407 if (newhashvalue != hashvalue)
2408 (*function) (ccp->id, newhashvalue, dbid, context);
2409 }
2410 }
2411 }
2412
2413 /* ResourceOwner callbacks */
2414
2415 static void
2416 ResOwnerReleaseCatCache(Datum res)
2417 {
2418 ReleaseCatCacheWithOwner((HeapTuple) DatumGetPointer(res), NULL);
2419 }
2420
2421 static char *
2422 ResOwnerPrintCatCache(Datum res)
2423 {
2424 HeapTuple tuple = (HeapTuple) DatumGetPointer(res);
2425 CatCTup *ct = (CatCTup *) (((char *) tuple) -
2426 offsetof(CatCTup, tuple));
2427
2428 /* Safety check to ensure we were handed a cache entry */
2429 Assert(ct->ct_magic == CT_MAGIC);
2430
2431 return psprintf("cache %s (%d), tuple %u/%u has count %d",
2432 ct->my_cache->cc_relname, ct->my_cache->id,
2433 ItemPointerGetBlockNumber(&(tuple->t_self)),
2434 ItemPointerGetOffsetNumber(&(tuple->t_self)),
2435 ct->refcount);
2436 }
2437
2438 static void
2439 ResOwnerReleaseCatCacheList(Datum res)
2440 {
2441 ReleaseCatCacheListWithOwner((CatCList *) DatumGetPointer(res), NULL);
2442 }
2443
2444 static char *
2445 ResOwnerPrintCatCacheList(Datum res)
2446 {
2447 CatCList *list = (CatCList *) DatumGetPointer(res);
2448
2449 return psprintf("cache %s (%d), list %p has count %d",
2450 list->my_cache->cc_relname, list->my_cache->id,
2451 list, list->refcount);
2452 }
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