From a2f606d5dba1d7902f925a1c9af95cd27ade7488 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Mon, 29 Jul 2024 18:03:44 +0200 Subject: [PATCH v20240730 2/6] atomic LSN counter --- src/backend/access/gist/gist.c | 24 ++++++++++++------------ src/backend/access/gist/gistbuild.c | 19 +++++++++++++++---- src/backend/access/gist/gistutil.c | 10 +++------- src/backend/access/gist/gistvacuum.c | 6 +++--- src/include/access/gist_private.h | 8 ++++---- 5 files changed, 37 insertions(+), 30 deletions(-) diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c index f5f56fb2503..63d5580120d 100644 --- a/src/backend/access/gist/gist.c +++ b/src/backend/access/gist/gist.c @@ -182,7 +182,7 @@ gistinsert(Relation r, Datum *values, bool *isnull, values, isnull, true /* size is currently bogus */ ); itup->t_tid = *ht_ctid; - gistdoinsert(r, itup, 0, giststate, heapRel, false, false); + gistdoinsert(r, itup, 0, giststate, heapRel, false, NULL); /* cleanup */ MemoryContextSwitchTo(oldCxt); @@ -231,7 +231,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, bool markfollowright, Relation heapRel, bool is_build, - bool is_parallel) + pg_atomic_uint64 *fakelsn) { BlockNumber blkno = BufferGetBlockNumber(buffer); Page page = BufferGetPage(buffer); @@ -508,8 +508,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, */ if (is_build) { - if (is_parallel) - recptr = gistGetFakeLSN(rel, is_parallel); + if (fakelsn) + recptr = pg_atomic_fetch_add_u64(fakelsn, 1); else recptr = GistBuildLSN; } @@ -520,7 +520,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, dist, oldrlink, oldnsn, leftchildbuf, markfollowright); else - recptr = gistGetFakeLSN(rel, false); + recptr = gistGetFakeLSN(rel); } for (ptr = dist; ptr; ptr = ptr->next) @@ -580,8 +580,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, if (is_build) { - if (is_parallel) - recptr = gistGetFakeLSN(rel, is_parallel); + if (fakelsn) + recptr = pg_atomic_fetch_add_u64(fakelsn, 1); else recptr = GistBuildLSN; } @@ -603,7 +603,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, leftchildbuf); } else - recptr = gistGetFakeLSN(rel, false); + recptr = gistGetFakeLSN(rel); } PageSetLSN(page, recptr); @@ -647,7 +647,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, void gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate, Relation heapRel, bool is_build, - bool is_parallel) + pg_atomic_uint64 *fakelsn) { ItemId iid; IndexTuple idxtuple; @@ -661,7 +661,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, state.r = r; state.heapRel = heapRel; state.is_build = is_build; - state.is_parallel = is_parallel; + state.fakelsn = fakelsn; /* Start from the root */ firststack.blkno = GIST_ROOT_BLKNO; @@ -1320,7 +1320,7 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack, true, state->heapRel, state->is_build, - state->is_parallel); + state->fakelsn); /* * Before recursing up in case the page was split, release locks on the @@ -1739,7 +1739,7 @@ gistprunepage(Relation rel, Page page, Buffer buffer, Relation heapRel) PageSetLSN(page, recptr); } else - PageSetLSN(page, gistGetFakeLSN(rel, false)); + PageSetLSN(page, gistGetFakeLSN(rel)); END_CRIT_SECTION(); } diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c index c8fa67beebb..c7ac2487cda 100644 --- a/src/backend/access/gist/gistbuild.c +++ b/src/backend/access/gist/gistbuild.c @@ -140,6 +140,9 @@ typedef struct GISTShared double reltuples; double indtuples; + /* Used to generate LSNs during parallel build. */ + pg_atomic_uint64 parallelLSN; + /* * ParallelTableScanDescData data follows. Can't directly embed here, as * implementations of the parallel table scan desc interface might need @@ -217,6 +220,7 @@ typedef struct */ bool is_parallel; GISTLeader *gist_leader; + pg_atomic_uint64 *fakelsn; /* * Extra data structures used during a sorting build. @@ -1043,7 +1047,7 @@ gistBuildCallback(Relation index, * locked, we call gistdoinsert directly. */ gistdoinsert(index, itup, buildstate->freespace, - buildstate->giststate, buildstate->heaprel, true, false); + buildstate->giststate, buildstate->heaprel, true, NULL); } MemoryContextSwitchTo(oldCtx); @@ -1098,6 +1102,7 @@ gistBuildParallelCallback(Relation index, void *state) { GISTBuildState *buildstate = (GISTBuildState *) state; + IndexTuple itup; MemoryContext oldCtx; @@ -1118,7 +1123,8 @@ gistBuildParallelCallback(Relation index, * locked, we call gistdoinsert directly. */ gistdoinsert(index, itup, buildstate->freespace, - buildstate->giststate, buildstate->heaprel, true, true); + buildstate->giststate, buildstate->heaprel, true, + buildstate->fakelsn); MemoryContextSwitchTo(oldCtx); MemoryContextReset(buildstate->giststate->tempCxt); @@ -1292,8 +1298,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level, InvalidBuffer, &splitinfo, false, - buildstate->heaprel, true, - buildstate->is_parallel); + buildstate->heaprel, true, NULL); /* * If this is a root split, update the root path item kept in memory. This @@ -1925,6 +1930,9 @@ _gist_begin_parallel(GISTBuildState *buildstate, Relation heap, Relation index, gistshared->reltuples = 0.0; gistshared->indtuples = 0.0; + /* initialize the counter used to generate fake LSNs */ + pg_atomic_init_u64(&gistshared->parallelLSN, 1); + table_parallelscan_initialize(heap, ParallelTableScanFromGistShared(gistshared), snapshot); @@ -1974,6 +1982,7 @@ _gist_begin_parallel(GISTBuildState *buildstate, Relation heap, Relation index, /* Save leader state now that it's clear build will be parallel */ buildstate->is_parallel = true; buildstate->gist_leader = gistleader; + buildstate->fakelsn = &gistshared->parallelLSN; /* Join heap scan ourselves */ if (leaderparticipates) @@ -2202,6 +2211,8 @@ _gist_parallel_build_main(dsm_segment *seg, shm_toc *toc) buildstate.is_parallel = true; buildstate.gist_leader = NULL; + buildstate.fakelsn = &gistshared->parallelLSN; + /* * Create a temporary memory context that is reset once for each tuple * processed. (Note: we don't bother to make this a child of the diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c index 733d5849317..78e98d68b15 100644 --- a/src/backend/access/gist/gistutil.c +++ b/src/backend/access/gist/gistutil.c @@ -1012,7 +1012,7 @@ gistproperty(Oid index_oid, int attno, * purpose. */ XLogRecPtr -gistGetFakeLSN(Relation rel, bool is_parallel) +gistGetFakeLSN(Relation rel) { if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP) { @@ -1035,12 +1035,8 @@ gistGetFakeLSN(Relation rel, bool is_parallel) static XLogRecPtr lastlsn = InvalidXLogRecPtr; XLogRecPtr currlsn = GetXLogInsertRecPtr(); - /* - * Shouldn't be called for WAL-logging relations, but parallell - * builds are an exception - we need the fake LSN to detect - * concurrent changes. - */ - Assert(is_parallel || !RelationNeedsWAL(rel)); + /* Shouldn't be called for WAL-logging relations */ + Assert(!RelationNeedsWAL(rel)); /* No need for an actual record if we already have a distinct LSN */ if (!XLogRecPtrIsInvalid(lastlsn) && lastlsn == currlsn) diff --git a/src/backend/access/gist/gistvacuum.c b/src/backend/access/gist/gistvacuum.c index 082804e9c7d..24fb94f473e 100644 --- a/src/backend/access/gist/gistvacuum.c +++ b/src/backend/access/gist/gistvacuum.c @@ -181,7 +181,7 @@ gistvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, if (RelationNeedsWAL(rel)) vstate.startNSN = GetInsertRecPtr(); else - vstate.startNSN = gistGetFakeLSN(rel, false); + vstate.startNSN = gistGetFakeLSN(rel); /* * The outer loop iterates over all index pages, in physical order (we @@ -376,7 +376,7 @@ restart: PageSetLSN(page, recptr); } else - PageSetLSN(page, gistGetFakeLSN(rel, false)); + PageSetLSN(page, gistGetFakeLSN(rel)); END_CRIT_SECTION(); @@ -664,7 +664,7 @@ gistdeletepage(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, if (RelationNeedsWAL(info->index)) recptr = gistXLogPageDelete(leafBuffer, txid, parentBuffer, downlink); else - recptr = gistGetFakeLSN(info->index, false); + recptr = gistGetFakeLSN(info->index); PageSetLSN(parentPage, recptr); PageSetLSN(leafPage, recptr); diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h index d5b22bc1018..09f535ff56e 100644 --- a/src/include/access/gist_private.h +++ b/src/include/access/gist_private.h @@ -255,7 +255,7 @@ typedef struct Relation heapRel; Size freespace; /* free space to be left */ bool is_build; - bool is_parallel; + pg_atomic_uint64 *fakelsn; GISTInsertStack *stack; } GISTInsertState; @@ -416,7 +416,7 @@ extern void gistdoinsert(Relation r, GISTSTATE *giststate, Relation heapRel, bool is_build, - bool is_parallel); + pg_atomic_uint64 *fakelsn); /* A List of these is returned from gistplacetopage() in *splitinfo */ typedef struct @@ -434,7 +434,7 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, bool markfollowright, Relation heapRel, bool is_build, - bool is_parallel); + pg_atomic_uint64 *fakelsn); extern SplitPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup, int len, GISTSTATE *giststate); @@ -535,7 +535,7 @@ extern void gistMakeUnionKey(GISTSTATE *giststate, int attno, GISTENTRY *entry2, bool isnull2, Datum *dst, bool *dstisnull); -extern XLogRecPtr gistGetFakeLSN(Relation rel, bool is_parallel); +extern XLogRecPtr gistGetFakeLSN(Relation rel); /* gistvacuum.c */ extern IndexBulkDeleteResult *gistbulkdelete(IndexVacuumInfo *info, -- 2.45.2