From 49a5fc72492f4917990bfeb7bd6c4fd06e52a7d5 Mon Sep 17 00:00:00 2001 From: "Andrey V. Lepikhov" Date: Tue, 31 Jul 2018 07:23:11 +0500 Subject: [PATCH 3/4] GIST-Optimal-WAL-Usage --- src/backend/access/gist/gist.c | 46 ++++++++++++++++++-------- src/backend/access/gist/gistbuild.c | 32 ++++++++++-------- src/backend/access/gist/gistutil.c | 2 +- src/backend/access/gist/gistxlog.c | 22 ------------ src/backend/access/rmgrdesc/gistdesc.c | 5 --- src/include/access/gist_private.h | 10 +++--- src/include/access/gistxlog.h | 1 - 7 files changed, 57 insertions(+), 61 deletions(-) diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c index 8a42effdf7..227998b1f8 100644 --- a/src/backend/access/gist/gist.c +++ b/src/backend/access/gist/gist.c @@ -172,7 +172,7 @@ gistinsert(Relation r, Datum *values, bool *isnull, values, isnull, true /* size is currently bogus */ ); itup->t_tid = *ht_ctid; - gistdoinsert(r, itup, 0, giststate); + gistdoinsert(r, itup, 0, giststate, false); /* cleanup */ MemoryContextSwitchTo(oldCxt); @@ -218,7 +218,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, BlockNumber *newblkno, Buffer leftchildbuf, List **splitinfo, - bool markfollowright) + bool markfollowright, + bool is_build) { BlockNumber blkno = BufferGetBlockNumber(buffer); Page page = BufferGetPage(buffer); @@ -457,7 +458,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, * insertion for that. NB: The number of pages and data segments * specified here must match the calculations in gistXLogSplit()! */ - if (RelationNeedsWAL(rel)) + if (RelationNeedsWAL(rel) && !is_build) XLogEnsureRecordSpace(npage, 1 + npage * 2); START_CRIT_SECTION(); @@ -478,18 +479,20 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer)); dist->page = BufferGetPage(dist->buffer); - /* Write the WAL record */ - if (RelationNeedsWAL(rel)) + /* + * Write the WAL record. + * Do not write XLog entry if the insertion is caused by + * index build process. + */ + if (RelationNeedsWAL(rel) && !is_build) recptr = gistXLogSplit(is_leaf, - dist, oldrlink, oldnsn, leftchildbuf, - markfollowright); + dist, oldrlink, oldnsn, leftchildbuf, + markfollowright); else recptr = gistGetFakeLSN(rel); for (ptr = dist; ptr; ptr = ptr->next) - { PageSetLSN(ptr->page, recptr); - } /* * Return the new child buffers to the caller. @@ -543,7 +546,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, if (BufferIsValid(leftchildbuf)) MarkBufferDirty(leftchildbuf); - if (RelationNeedsWAL(rel)) + + if (RelationNeedsWAL(rel) && !is_build) { OffsetNumber ndeloffs = 0, deloffs[1]; @@ -566,6 +570,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, PageSetLSN(page, recptr); } + if (newblkno) *newblkno = blkno; } @@ -582,17 +587,28 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, * the full page image. There's a chicken-and-egg problem: if we updated * the child pages first, we wouldn't know the recptr of the WAL record * we're about to write. + * + * We use fakeLSNs for inserions caused by index build. And when it is + * finished, we write generic_xlog entry for each index page and update + * all LSNs. In order to keep NSNs less then LSNs after this update, we + * set NSN to InvalidXLogRecPtr, which is the smallest possible NSN. */ + if (BufferIsValid(leftchildbuf)) { Page leftpg = BufferGetPage(leftchildbuf); + XLogRecPtr fakerecptr = InvalidXLogRecPtr; - GistPageSetNSN(leftpg, recptr); - GistClearFollowRight(leftpg); + if (!is_build) + GistPageSetNSN(leftpg, recptr); + else + GistPageSetNSN(leftpg, fakerecptr); + GistClearFollowRight(leftpg); PageSetLSN(leftpg, recptr); } + END_CRIT_SECTION(); return is_split; @@ -604,7 +620,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, * so it does not bother releasing palloc'd allocations. */ void -gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate) +gistdoinsert(Relation r, IndexTuple itup, Size freespace, + GISTSTATE *giststate, bool is_build) { ItemId iid; IndexTuple idxtuple; @@ -616,6 +633,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate) memset(&state, 0, sizeof(GISTInsertState)); state.freespace = freespace; state.r = r; + state.is_build = is_build; /* Start from the root */ firststack.blkno = GIST_ROOT_BLKNO; @@ -1232,7 +1250,7 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack, oldoffnum, NULL, leftchild, &splitinfo, - true); + true, state->is_build); /* * Before recursing up in case the page was split, release locks on the diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c index 434f15f014..b61dbf8ac3 100644 --- a/src/backend/access/gist/gistbuild.c +++ b/src/backend/access/gist/gistbuild.c @@ -20,6 +20,7 @@ #include "access/gist_private.h" #include "access/gistxlog.h" #include "access/xloginsert.h" +#include "access/generic_xlog.h" #include "catalog/index.h" #include "miscadmin.h" #include "optimizer/cost.h" @@ -178,18 +179,12 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo) MarkBufferDirty(buffer); - if (RelationNeedsWAL(index)) - { - XLogRecPtr recptr; - - XLogBeginInsert(); - XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT); - - recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX); - PageSetLSN(page, recptr); - } - else - PageSetLSN(page, gistGetFakeLSN(heap)); + /* + * Do not write index pages to WAL unitl index build is finished. + * But we still need increasing LSNs on each page, so use FakeLSN, + * even for relations which eventually need WAL. + */ + PageSetLSN(page, gistGetFakeLSN(heap)); UnlockReleaseBuffer(buffer); @@ -222,6 +217,15 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo) freeGISTstate(buildstate.giststate); + /* + * Create generic wal records for all pages of relation, if necessary. + * It seems reasonable not to generate WAL, if we recieved interrupt + * signal. + */ + CHECK_FOR_INTERRUPTS(); + if (RelationNeedsWAL(index)) + generic_log_relation(index); + /* * Return statistics */ @@ -484,7 +488,7 @@ gistBuildCallback(Relation index, * locked, we call gistdoinsert directly. */ gistdoinsert(index, itup, buildstate->freespace, - buildstate->giststate); + buildstate->giststate, true); } /* Update tuple count and total size. */ @@ -690,7 +694,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level, itup, ntup, oldoffnum, &placed_to_blk, InvalidBuffer, &splitinfo, - false); + false, true); /* * If this is a root split, update the root path item kept in memory. This diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c index 12804c321c..0b3f8db679 100644 --- a/src/backend/access/gist/gistutil.c +++ b/src/backend/access/gist/gistutil.c @@ -974,6 +974,7 @@ gistproperty(Oid index_oid, int attno, * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs * to detect concurrent page splits anyway. This function provides a fake * sequence of LSNs for that purpose. + * Persistent relations are also not WAL-logged while we build index. */ XLogRecPtr gistGetFakeLSN(Relation rel) @@ -994,7 +995,6 @@ gistGetFakeLSN(Relation rel) * Unlogged relations are accessible from other backends, and survive * (clean) restarts. GetFakeLSNForUnloggedRel() handles that for us. */ - Assert(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED); return GetFakeLSNForUnloggedRel(); } } diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c index 1e09126978..9b0abccdaf 100644 --- a/src/backend/access/gist/gistxlog.c +++ b/src/backend/access/gist/gistxlog.c @@ -281,25 +281,6 @@ gistRedoPageSplitRecord(XLogReaderState *record) UnlockReleaseBuffer(firstbuffer); } -static void -gistRedoCreateIndex(XLogReaderState *record) -{ - XLogRecPtr lsn = record->EndRecPtr; - Buffer buffer; - Page page; - - buffer = XLogInitBufferForRedo(record, 0); - Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO); - page = (Page) BufferGetPage(buffer); - - GISTInitBuffer(buffer, F_LEAF); - - PageSetLSN(page, lsn); - - MarkBufferDirty(buffer); - UnlockReleaseBuffer(buffer); -} - void gist_redo(XLogReaderState *record) { @@ -321,9 +302,6 @@ gist_redo(XLogReaderState *record) case XLOG_GIST_PAGE_SPLIT: gistRedoPageSplitRecord(record); break; - case XLOG_GIST_CREATE_INDEX: - gistRedoCreateIndex(record); - break; default: elog(PANIC, "gist_redo: unknown op code %u", info); } diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c index e5e925e0c5..1685a2fb8a 100644 --- a/src/backend/access/rmgrdesc/gistdesc.c +++ b/src/backend/access/rmgrdesc/gistdesc.c @@ -44,8 +44,6 @@ gist_desc(StringInfo buf, XLogReaderState *record) case XLOG_GIST_PAGE_SPLIT: out_gistxlogPageSplit(buf, (gistxlogPageSplit *) rec); break; - case XLOG_GIST_CREATE_INDEX: - break; } } @@ -62,9 +60,6 @@ gist_identify(uint8 info) case XLOG_GIST_PAGE_SPLIT: id = "PAGE_SPLIT"; break; - case XLOG_GIST_CREATE_INDEX: - id = "CREATE_INDEX"; - break; } return id; diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h index 36ed7244ba..0588fc716a 100644 --- a/src/include/access/gist_private.h +++ b/src/include/access/gist_private.h @@ -241,6 +241,7 @@ typedef struct { Relation r; Size freespace; /* free space to be left */ + bool is_build; GISTInsertStack *stack; } GISTInsertState; @@ -387,9 +388,9 @@ extern MemoryContext createTempGistContext(void); extern GISTSTATE *initGISTstate(Relation index); extern void freeGISTstate(GISTSTATE *giststate); extern void gistdoinsert(Relation r, - IndexTuple itup, - Size freespace, - GISTSTATE *GISTstate); + IndexTuple itup, + Size freespace, + GISTSTATE* giststate, bool is_build); /* A List of these is returned from gistplacetopage() in *splitinfo */ typedef struct @@ -404,7 +405,8 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, OffsetNumber oldoffnum, BlockNumber *newblkno, Buffer leftchildbuf, List **splitinfo, - bool markleftchild); + bool markleftchild, + bool is_build); extern SplitedPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup, int len, GISTSTATE *giststate); diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h index 1a2b9496d0..5932fc395b 100644 --- a/src/include/access/gistxlog.h +++ b/src/include/access/gistxlog.h @@ -21,7 +21,6 @@ /* #define XLOG_GIST_NEW_ROOT 0x20 */ /* not used anymore */ #define XLOG_GIST_PAGE_SPLIT 0x30 /* #define XLOG_GIST_INSERT_COMPLETE 0x40 */ /* not used anymore */ -#define XLOG_GIST_CREATE_INDEX 0x50 /* #define XLOG_GIST_PAGE_DELETE 0x60 */ /* not used anymore */ /* -- 2.17.1