Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit81d08fc

Browse files
committed
Rename and document some invalidation routines to make it clearer that
they don't themselves flush any cache entries, only add to to-do liststhat will be processed later.
1 parent2fb6cc9 commit81d08fc

File tree

3 files changed

+106
-50
lines changed

3 files changed

+106
-50
lines changed

‎src/backend/utils/cache/catcache.c

Lines changed: 30 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.73 2000/11/24 04:16:12 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.74 2001/01/05 22:54:37 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -1047,17 +1047,36 @@ ReleaseCatCache(HeapTuple tuple)
10471047
}
10481048

10491049
/* --------------------------------
1050-
*RelationInvalidateCatalogCacheTuple()
1050+
*PrepareToInvalidateCacheTuple()
10511051
*
1052-
*Invalidate a tuple from a specific relation. This call determines the
1053-
*cache in question and calls CatalogCacheIdInvalidate(). It is -ok-
1054-
*if the relation cannot be found, it simply means this backend has yet
1055-
*to open it.
1052+
*This is part of a rather subtle chain of events, so pay attention:
1053+
*
1054+
*When a tuple is updated or deleted, it cannot be flushed from the
1055+
*catcaches immediately, for reasons explained at the top of inval.c.
1056+
*Instead we have to add entry(s) for the tuple to a list of pending tuple
1057+
*invalidations that will be done at the end of the command or transaction.
1058+
*
1059+
*The lists of tuples that need to be flushed are kept by inval.c. This
1060+
*routine is a helper routine for inval.c. Given a tuple belonging to
1061+
*the specified relation, find all catcaches it could be in, compute the
1062+
*correct hashindex for each such catcache, and call the specified function
1063+
*to record the cache id, hashindex, and tuple ItemPointer in inval.c's
1064+
*lists. CatalogCacheIdInvalidate will be called later, if appropriate,
1065+
*using the recorded information.
1066+
*
1067+
*Note that it is irrelevant whether the given tuple is actually loaded
1068+
*into the catcache at the moment. Even if it's not there now, it might
1069+
*be by the end of the command, so we have to be prepared to flush it.
1070+
*
1071+
*Also note that it's not an error if there are no catcaches for the
1072+
*specified relation. inval.c doesn't know exactly which rels have
1073+
*catcaches --- it will call this routine for any tuple that's in a
1074+
*system relation.
10561075
* --------------------------------
10571076
*/
10581077
void
1059-
RelationInvalidateCatalogCacheTuple(Relationrelation,
1060-
HeapTupletuple,
1078+
PrepareToInvalidateCacheTuple(Relationrelation,
1079+
HeapTupletuple,
10611080
void (*function) (int,Index,ItemPointer))
10621081
{
10631082
CatCache*ccp;
@@ -1069,13 +1088,13 @@ RelationInvalidateCatalogCacheTuple(Relation relation,
10691088
Assert(RelationIsValid(relation));
10701089
Assert(HeapTupleIsValid(tuple));
10711090
Assert(PointerIsValid(function));
1072-
CACHE1_elog(DEBUG,"RelationInvalidateCatalogCacheTuple: called");
1091+
CACHE1_elog(DEBUG,"PrepareToInvalidateCacheTuple: called");
10731092

10741093
/* ----------------
10751094
*for each cache
10761095
* if the cache contains tuples from the specified relation
1077-
*call theinvalidation function on the tuples
1078-
*intheproper hash bucket
1096+
*compute thetuple's hash index in this cache,
1097+
*and callthepassed function to register the information.
10791098
* ----------------
10801099
*/
10811100

‎src/backend/utils/cache/inval.c

Lines changed: 74 additions & 37 deletions
Original file line numberDiff line numberDiff line change
@@ -3,14 +3,41 @@
33
* inval.c
44
* POSTGRES cache invalidation dispatcher code.
55
*
6+
*This is subtle stuff, so pay attention:
7+
*
8+
*When a tuple is updated or deleted, our time qualification rules consider
9+
*that it is *still valid* so long as we are in the same command, ie,
10+
*until the next CommandCounterIncrement() or transaction commit.
11+
*(See utils/time/tqual.c.) At the command boundary, the old tuple stops
12+
*being valid and the new version, if any, becomes valid. Therefore,
13+
*we cannot simply flush a tuple from the system caches during heap_update()
14+
*or heap_delete(). The tuple is still good at that point; what's more,
15+
*even if we did flush it, it might be reloaded into the caches by a later
16+
*request in the same command. So the correct behavior is to keep a list
17+
*of outdated (updated/deleted) tuples and then do the required cache
18+
*flushes at the next command boundary. Similarly, we need a list of
19+
*inserted tuples (including new versions of updated tuples), which we will
20+
*use to flush those tuples out of the caches if we abort the transaction.
21+
*Notice that the first list lives only till command boundary, whereas the
22+
*second lives till end of transaction. Finally, we need a third list of
23+
*all tuples outdated in the current transaction; if we commit, we send
24+
*those invalidation events to all other backends (via the SI message queue)
25+
*so that they can flush obsolete entries from their caches.
26+
*
27+
*We do not need to register EVERY tuple operation in this way, just those
28+
*on tuples in relations that have associated catcaches. Also, whenever
29+
*we see an operation on a pg_class or pg_attribute tuple, we register
30+
*a relcache flush operation for the relation described by that tuple.
31+
*
32+
*
633
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
734
* Portions Copyright (c) 1994, Regents of the University of California
835
*
9-
*
1036
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/utils/cache/inval.c,v 1.38 2000/11/08 22:10:01 tgl Exp $
37+
* $Header: /cvsroot/pgsql/src/backend/utils/cache/inval.c,v 1.39 2001/01/05 22:54:37 tgl Exp $
1238
*
13-
* Note - this code is real crufty...
39+
* Note - this code is real crufty... badly needs a rewrite to improve
40+
* readability and portability. (Shouldn't assume Oid == Index, for example)
1441
*
1542
*-------------------------------------------------------------------------
1643
*/
@@ -82,7 +109,8 @@ typedef InvalidationMessageData *InvalidationMessage;
82109
* ----------------
83110
*Invalidation info is divided into three parts.
84111
*1) shared invalidation to be registered for all backends
85-
*2) local invalidation for the transaction itself
112+
*2) local invalidation for the transaction itself (actually, just
113+
* for the current command within the transaction)
86114
*3) rollback information for the transaction itself (in case we abort)
87115
* ----------------
88116
*/
@@ -107,7 +135,9 @@ static LocalInvalid RollbackStack = EmptyLocalInvalid;
107135

108136

109137
staticInvalidationEntryInvalidationEntryAllocate(uint16size);
110-
staticvoidLocalInvalidInvalidate(LocalInvalidinvalid,void (*function) (),boolfreemember);
138+
staticvoidLocalInvalidInvalidate(LocalInvalidinvalid,
139+
void (*function) (InvalidationMessage),
140+
boolfreemember);
111141
staticLocalInvalidLocalInvalidRegister(LocalInvalidinvalid,
112142
InvalidationEntryentry);
113143
staticvoidDiscardInvalidStack(LocalInvalid*invalid);
@@ -161,7 +191,7 @@ LocalInvalidRegister(LocalInvalid invalid,
161191
*/
162192
staticvoid
163193
LocalInvalidInvalidate(LocalInvalidinvalid,
164-
void (*function) (),
194+
void (*function) (InvalidationMessage),
165195
boolfreemember)
166196
{
167197
InvalidationEntryData*entryDataP;
@@ -172,7 +202,7 @@ LocalInvalidInvalidate(LocalInvalid invalid,
172202
&((InvalidationUserData*)invalid)->dataP[-1];
173203

174204
if (PointerIsValid(function))
175-
(*function) ((Pointer)&entryDataP->userData);
205+
(*function) ((InvalidationMessage)&entryDataP->userData);
176206

177207
invalid= (Pointer)entryDataP->nextP;
178208

@@ -193,7 +223,9 @@ DiscardInvalidStack(LocalInvalid *invalid)
193223
locinv=*invalid;
194224
*invalid=EmptyLocalInvalid;
195225
if (locinv)
196-
LocalInvalidInvalidate(locinv, (void (*) ())NULL, true);
226+
LocalInvalidInvalidate(locinv,
227+
(void (*) (InvalidationMessage))NULL,
228+
true);
197229
}
198230

199231
/* ----------------------------------------------------------------
@@ -269,7 +301,7 @@ CacheIdRegisterSpecifiedLocalInvalid(LocalInvalid invalid,
269301
* --------------------------------
270302
*/
271303
staticvoid
272-
CacheIdRegisterLocalInvalid(IndexcacheId,
304+
CacheIdRegisterLocalInvalid(intcacheId,
273305
IndexhashIndex,
274306
ItemPointerpointer)
275307
{
@@ -298,7 +330,8 @@ CacheIdRegisterLocalInvalid(Index cacheId,
298330
* --------------------------------
299331
*/
300332
staticvoid
301-
CacheIdRegisterLocalRollback(IndexcacheId,IndexhashIndex,
333+
CacheIdRegisterLocalRollback(intcacheId,
334+
IndexhashIndex,
302335
ItemPointerpointer)
303336
{
304337

@@ -477,7 +510,7 @@ CacheIdInvalidate(Index cacheId,
477510
* --------------------------------
478511
*/
479512
staticvoid
480-
ResetSystemCaches()
513+
ResetSystemCaches(void)
481514
{
482515
ResetSystemCache();
483516
RelationCacheInvalidate();
@@ -585,13 +618,13 @@ InvalidationMessageCacheInvalidate(InvalidationMessage message)
585618
}
586619

587620
/* --------------------------------
588-
*RelationInvalidateRelationCache
621+
*PrepareToInvalidateRelationCache
589622
* --------------------------------
590623
*/
591624
staticvoid
592-
RelationInvalidateRelationCache(Relationrelation,
593-
HeapTupletuple,
594-
void (*function) ())
625+
PrepareToInvalidateRelationCache(Relationrelation,
626+
HeapTupletuple,
627+
void (*function) (Oid,Oid))
595628
{
596629
OidrelationId;
597630
OidobjectId;
@@ -614,7 +647,7 @@ RelationInvalidateRelationCache(Relation relation,
614647
return;
615648

616649
/* ----------------
617-
* can't handle immediate relation descriptor invalidation
650+
*register the relcache-invalidation action in the appropriate list
618651
* ----------------
619652
*/
620653
Assert(PointerIsValid(function));
@@ -629,11 +662,9 @@ RelationInvalidateRelationCache(Relation relation,
629662
*
630663
* Note:
631664
*This should be called as the first step in processing a transaction.
632-
*This should be called while waiting for a query from the front end
633-
*when other backends are active.
634665
*/
635666
void
636-
DiscardInvalid()
667+
DiscardInvalid(void)
637668
{
638669
/* ----------------
639670
*debugging stuff
@@ -694,7 +725,8 @@ RegisterInvalid(bool send)
694725
*Causes invalidation immediately for the next command of the transaction.
695726
*
696727
* Note:
697-
*This should be called in time of CommandCounterIncrement().
728+
*This should be called during CommandCounterIncrement(),
729+
*after we have advanced the command ID.
698730
*/
699731
void
700732
ImmediateLocalInvalidation(boolsend)
@@ -735,28 +767,29 @@ ImmediateLocalInvalidation(bool send)
735767
}
736768

737769
/*
738-
*InvokeHeapTupleInvalidation
770+
*PrepareForTupleInvalidation
739771
*Invoke functions for the tuple which register invalidation
740772
*of catalog/relation cache.
741773
*Note:
742774
*Assumes object id is valid.
743775
*Assumes tuple is valid.
744776
*/
745777
#ifdefINVALIDDEBUG
746-
#defineInvokeHeapTupleInvalidation_DEBUG1 \
778+
#definePrepareForTupleInvalidation_DEBUG1 \
747779
elog(DEBUG, "%s(%s, [%d,%d])", \
748780
funcname,\
749781
RelationGetPhysicalRelationName(relation), \
750782
ItemPointerGetBlockNumber(&tuple->t_self), \
751783
ItemPointerGetOffsetNumber(&tuple->t_self))
752784
#else
753-
#defineInvokeHeapTupleInvalidation_DEBUG1
785+
#definePrepareForTupleInvalidation_DEBUG1
754786
#endif/* defined(INVALIDDEBUG) */
755787

756788
staticvoid
757-
InvokeHeapTupleInvalidation(Relationrelation,HeapTupletuple,
758-
void (*CacheIdRegisterFunc) (),
759-
void (*RelationIdRegisterFunc) (),
789+
PrepareForTupleInvalidation(Relationrelation,HeapTupletuple,
790+
void (*CacheIdRegisterFunc) (int,Index,
791+
ItemPointer),
792+
void (*RelationIdRegisterFunc) (Oid,Oid),
760793
constchar*funcname)
761794
{
762795
/* ----------------
@@ -768,8 +801,11 @@ InvokeHeapTupleInvalidation(Relation relation, HeapTuple tuple,
768801

769802
if (IsBootstrapProcessingMode())
770803
return;
804+
771805
/* ----------------
772-
*this only works for system relations now
806+
*We only need to worry about invalidation for tuples that are in
807+
*system relations; user-relation tuples are never in catcaches
808+
*and can't affect the relcache either.
773809
* ----------------
774810
*/
775811
if (!IsSystemRelationName(NameStr(RelationGetForm(relation)->relname)))
@@ -779,37 +815,38 @@ InvokeHeapTupleInvalidation(Relation relation, HeapTuple tuple,
779815
*debugging stuff
780816
* ----------------
781817
*/
782-
InvokeHeapTupleInvalidation_DEBUG1;
818+
PrepareForTupleInvalidation_DEBUG1;
783819

784-
RelationInvalidateCatalogCacheTuple(relation,tuple,
785-
CacheIdRegisterFunc);
820+
PrepareToInvalidateCacheTuple(relation,tuple,
821+
CacheIdRegisterFunc);
786822

787-
RelationInvalidateRelationCache(relation,tuple,
788-
RelationIdRegisterFunc);
823+
PrepareToInvalidateRelationCache(relation,tuple,
824+
RelationIdRegisterFunc);
789825
}
790826

791827
/*
792828
* RelationInvalidateHeapTuple
793-
*Causes the given tuple in a relation to be invalidated.
829+
*Register the given tuple for invalidation at end of command
830+
*(ie, current command is outdating this tuple).
794831
*/
795832
void
796833
RelationInvalidateHeapTuple(Relationrelation,HeapTupletuple)
797834
{
798-
InvokeHeapTupleInvalidation(relation,tuple,
835+
PrepareForTupleInvalidation(relation,tuple,
799836
CacheIdRegisterLocalInvalid,
800837
RelationIdRegisterLocalInvalid,
801838
"RelationInvalidateHeapTuple");
802839
}
803840

804841
/*
805842
* RelationMark4RollbackHeapTuple
806-
*keep the given tuplein a relation to be invalidated
807-
*in case of abort.
843+
*Register the given tuplefor invalidation in case of abort
844+
*(ie, current command is creating this tuple).
808845
*/
809846
void
810847
RelationMark4RollbackHeapTuple(Relationrelation,HeapTupletuple)
811848
{
812-
InvokeHeapTupleInvalidation(relation,tuple,
849+
PrepareForTupleInvalidation(relation,tuple,
813850
CacheIdRegisterLocalRollback,
814851
RelationIdRegisterLocalRollback,
815852
"RelationMark4RollbackHeapTuple");

‎src/include/utils/catcache.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
1414
* Portions Copyright (c) 1994, Regents of the University of California
1515
*
16-
* $Id: catcache.h,v 1.29 2000/11/24 04:16:11 tgl Exp $
16+
* $Id: catcache.h,v 1.30 2001/01/05 22:54:37 tgl Exp $
1717
*
1818
*-------------------------------------------------------------------------
1919
*/
@@ -95,7 +95,7 @@ extern void ResetSystemCache(void);
9595
externvoidSystemCacheRelationFlushed(OidrelId);
9696
externvoidCatalogCacheIdInvalidate(intcacheId,IndexhashIndex,
9797
ItemPointerpointer);
98-
externvoidRelationInvalidateCatalogCacheTuple(Relationrelation,
98+
externvoidPrepareToInvalidateCacheTuple(Relationrelation,
9999
HeapTupletuple,
100100
void (*function) (int,Index,ItemPointer));
101101

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp