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Predicate locking in GIN index

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Predicate locks are used on per page basis only if fastupdate = off, in
opposite case predicate lock on pending list will effectively lock whole index,
to reduce locking overhead, just lock a relation. Entry and posting trees are
essentially B-tree, so locks are acquired on leaf pages only.

Author: Shubham Barai with some editorization by me and Dmitry Ivanov
Review by: Alexander Korotkov, Dmitry Ivanov, Fedor Sigaev
Discussion: https://www.postgresql.org/message-id/flat/CALxAEPt5sWW+EwTaKUGFL5_XFcZ0MuGBcyJ70oqbWqr42YKR8Q@mail.gmail.com
This commit is contained in:
Teodor Sigaev
2018-03-30 14:23:17 +03:00
parent 019fa576ca
commit 43d1ed60fd
11 changed files with 1054 additions and 18 deletions
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38
src/backend/access/gin/gininsert.c
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@@ -22,6 +22,7 @@
#include "storage/bufmgr.h"
#include "storage/smgr.h"
#include "storage/indexfsm.h"
#include "storage/predicate.h"
#include "utils/memutils.h"
#include "utils/rel.h"
@@ -48,7 +49,7 @@ static IndexTuple
addItemPointersToLeafTuple(GinState *ginstate,
IndexTuple old,
ItemPointerData *items, uint32 nitem,
GinStatsData *buildStats)
GinStatsData *buildStats, Buffer buffer)
{
OffsetNumber attnum;
Datum key;
@@ -99,7 +100,8 @@ addItemPointersToLeafTuple(GinState *ginstate,
postingRoot = createPostingTree(ginstate->index,
oldItems,
oldNPosting,
buildStats);
buildStats,
buffer);
/* Now insert the TIDs-to-be-added into the posting tree */
ginInsertItemPointers(ginstate->index, postingRoot,
@@ -127,7 +129,7 @@ static IndexTuple
buildFreshLeafTuple(GinState *ginstate,
OffsetNumber attnum, Datum key, GinNullCategory category,
ItemPointerData *items, uint32 nitem,
GinStatsData *buildStats)
GinStatsData *buildStats, Buffer buffer)
{
IndexTuple res = NULL;
GinPostingList *compressedList;
@@ -157,7 +159,7 @@ buildFreshLeafTuple(GinState *ginstate,
* Initialize a new posting tree with the TIDs.
*/
postingRoot = createPostingTree(ginstate->index, items, nitem,
buildStats);
buildStats, buffer);
/* And save the root link in the result tuple */
GinSetPostingTree(res, postingRoot);
@@ -217,17 +219,19 @@ ginEntryInsert(GinState *ginstate,
return;
}
GinCheckForSerializableConflictIn(btree.index, NULL, stack->buffer);
/* modify an existing leaf entry */
itup = addItemPointersToLeafTuple(ginstate, itup,
items, nitem, buildStats);
items, nitem, buildStats, stack->buffer);
insertdata.isDelete = true;
}
else
{
GinCheckForSerializableConflictIn(btree.index, NULL, stack->buffer);
/* no match, so construct a new leaf entry */
itup = buildFreshLeafTuple(ginstate, attnum, key, category,
items, nitem, buildStats);
items, nitem, buildStats, stack->buffer);
}
/* Insert the new or modified leaf tuple */
@@ -513,6 +517,18 @@ gininsert(Relation index, Datum *values, bool *isnull,
memset(&collector, 0, sizeof(GinTupleCollector));
/*
* With fastupdate on each scan and each insert begin with access to
* pending list, so it effectively lock entire index. In this case
* we aquire predicate lock and check for conflicts over index relation,
* and hope that it will reduce locking overhead.
*
* Do not use GinCheckForSerializableConflictIn() here, because
* it will do nothing (it does actual work only with fastupdate off).
* Check for conflicts for entire index.
*/
CheckForSerializableConflictIn(index, NULL, InvalidBuffer);
for (i = 0; i < ginstate->origTupdesc->natts; i++)
ginHeapTupleFastCollect(ginstate, &collector,
(OffsetNumber) (i + 1),
@@ -523,6 +539,16 @@ gininsert(Relation index, Datum *values, bool *isnull,
}
else
{
GinStatsData stats;
/*
* Fastupdate is off but if pending list isn't empty then we need to
* check conflicts with PredicateLockRelation in scanPendingInsert().
*/
ginGetStats(index, &stats);
if (stats.nPendingPages > 0)
CheckForSerializableConflictIn(index, NULL, InvalidBuffer);
for (i = 0; i < ginstate->origTupdesc->natts; i++)
ginHeapTupleInsert(ginstate, (OffsetNumber) (i + 1),
values[i], isnull[i],