From: Tom Lane Date: Sat, 11 Feb 2006 23:31:34 +0000 (+0000) Subject: Skip ambulkdelete scan if there's nothing to delete and the index is not X-Git-Tag: REL9_0_0~8423 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=fd267c1ebc363ae6b1bf586794fa5cc9e8cca43c;p=pg-rex%2Fsyncrep.git Skip ambulkdelete scan if there's nothing to delete and the index is not partial. None of the existing AMs do anything useful except counting tuples when there's nothing to delete, and we can get a tuple count from the heap as long as it's not a partial index. (hash actually can skip anyway because it maintains a tuple count in the index metapage.) GIST is not currently able to exploit this optimization because, due to failure to index NULLs, GIST is always effectively partial. Possibly we should fix that sometime. Simon Riggs w/ some review by Tom Lane. --- diff --git a/doc/src/sgml/indexam.sgml b/doc/src/sgml/indexam.sgml index 7480c98a15..d766467bdb 100644 --- a/doc/src/sgml/indexam.sgml +++ b/doc/src/sgml/indexam.sgml @@ -1,5 +1,5 @@ @@ -201,6 +201,12 @@ ambulkdelete (Relation indexRelation, + If callback_state is NULL then no tuples are to be deleted. + The index AM may choose to optimize this case (eg by not scanning the + index) but it is still expected to deliver accurate statistics. + + + IndexBulkDeleteResult * amvacuumcleanup (Relation indexRelation, diff --git a/src/backend/access/gist/gistvacuum.c b/src/backend/access/gist/gistvacuum.c index afd743a5a2..b96d84fd02 100644 --- a/src/backend/access/gist/gistvacuum.c +++ b/src/backend/access/gist/gistvacuum.c @@ -8,7 +8,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.13 2006/02/11 17:14:08 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.14 2006/02/11 23:31:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -25,16 +25,19 @@ #include "storage/freespace.h" #include "storage/smgr.h" -/* filled by gistbulkdelete, cleared by gistvacuumpcleanup */ -static bool needFullVacuum = false; +typedef struct GistBulkDeleteResult +{ + IndexBulkDeleteResult std; /* common state */ + bool needFullVacuum; +} GistBulkDeleteResult; typedef struct { GISTSTATE giststate; Relation index; MemoryContext opCtx; - IndexBulkDeleteResult *result; + GistBulkDeleteResult *result; } GistVacuum; typedef struct @@ -44,6 +47,7 @@ typedef struct bool emptypage; } ArrayTuple; + static ArrayTuple gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion) { @@ -125,7 +129,7 @@ gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion) if (chldtuple.ituplen > 1) { /* - * child was splitted, so we need mark completion + * child was split, so we need mark completion * insert(split) */ int j; @@ -262,7 +266,7 @@ gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion) needwrite = true; res.emptypage = true; GistPageSetDeleted(page); - gv->result->pages_deleted++; + gv->result->std.pages_deleted++; } } else @@ -329,9 +333,9 @@ gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion) } /* - * For usial vacuum just update FSM, for full vacuum + * For usual vacuum just update FSM, for full vacuum * reforms parent tuples if some of childs was deleted or changed, - * update invalid tuples (they can exsist from last crash recovery only), + * update invalid tuples (they can exist from last crash recovery only), * tries to get smaller index */ @@ -340,7 +344,7 @@ gistvacuumcleanup(PG_FUNCTION_ARGS) { Relation rel = (Relation) PG_GETARG_POINTER(0); IndexVacuumCleanupInfo *info = (IndexVacuumCleanupInfo *) PG_GETARG_POINTER(1); - IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(2); + GistBulkDeleteResult *stats = (GistBulkDeleteResult *) PG_GETARG_POINTER(2); BlockNumber npages, blkno; BlockNumber nFreePages, @@ -377,13 +381,11 @@ gistvacuumcleanup(PG_FUNCTION_ARGS) freeGISTstate(&(gv.giststate)); MemoryContextDelete(gv.opCtx); } - else if (needFullVacuum) + else if (stats->needFullVacuum) ereport(NOTICE, (errmsg("index \"%s\" needs VACUUM FULL or REINDEX to finish crash recovery", RelationGetRelationName(rel)))); - needFullVacuum = false; - if (info->vacuum_full) needLock = false; /* relation locked with AccessExclusiveLock */ else @@ -438,23 +440,30 @@ gistvacuumcleanup(PG_FUNCTION_ARGS) if (lastBlock > lastFilledBlock) RelationTruncate(rel, lastFilledBlock + 1); - stats->pages_removed = lastBlock - lastFilledBlock; + stats->std.pages_removed = lastBlock - lastFilledBlock; } RecordIndexFreeSpace(&rel->rd_node, nFreePages, freePages); pfree(freePages); /* return statistics */ - stats->pages_free = nFreePages; + stats->std.pages_free = nFreePages; if (needLock) LockRelationForExtension(rel, ExclusiveLock); - stats->num_pages = RelationGetNumberOfBlocks(rel); + stats->std.num_pages = RelationGetNumberOfBlocks(rel); if (needLock) UnlockRelationForExtension(rel, ExclusiveLock); if (info->vacuum_full) UnlockRelation(rel, AccessExclusiveLock); + /* if gistbulkdelete skipped the scan, use heap's tuple count */ + if (stats->std.num_index_tuples < 0) + { + Assert(info->num_heap_tuples >= 0); + stats->std.num_index_tuples = info->num_heap_tuples; + } + PG_RETURN_POINTER(stats); } @@ -500,15 +509,33 @@ gistbulkdelete(PG_FUNCTION_ARGS) Relation rel = (Relation) PG_GETARG_POINTER(0); IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(1); void *callback_state = (void *) PG_GETARG_POINTER(2); - IndexBulkDeleteResult *result = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult)); + GistBulkDeleteResult *result; GistBDItem *stack, *ptr; bool needLock; - stack = (GistBDItem *) palloc0(sizeof(GistBDItem)); + result = (GistBulkDeleteResult *) palloc0(sizeof(GistBulkDeleteResult)); - stack->blkno = GIST_ROOT_BLKNO; - needFullVacuum = false; + /* + * We can skip the scan entirely if there's nothing to delete (indicated + * by callback_state == NULL) and the index isn't partial. For a partial + * index we must scan in order to derive a trustworthy tuple count. + * + * XXX as of PG 8.2 this is dead code because GIST indexes are always + * effectively partial ... but keep it anyway in case our null-handling + * gets fixed. + */ + if (callback_state || vac_is_partial_index(rel)) + { + stack = (GistBDItem *) palloc0(sizeof(GistBDItem)); + stack->blkno = GIST_ROOT_BLKNO; + } + else + { + /* skip scan and set flag for gistvacuumcleanup */ + stack = NULL; + result->std.num_index_tuples = -1; + } while (stack) { @@ -561,11 +588,11 @@ gistbulkdelete(PG_FUNCTION_ARGS) i--; maxoff--; ntodelete++; - result->tuples_removed += 1; + result->std.tuples_removed += 1; Assert(maxoff == PageGetMaxOffsetNumber(page)); } else - result->num_index_tuples += 1; + result->std.num_index_tuples += 1; } if (ntodelete) @@ -615,7 +642,7 @@ gistbulkdelete(PG_FUNCTION_ARGS) stack->next = ptr; if (GistTupleIsInvalid(idxtuple)) - needFullVacuum = true; + result->needFullVacuum = true; } } @@ -634,7 +661,7 @@ gistbulkdelete(PG_FUNCTION_ARGS) if (needLock) LockRelationForExtension(rel, ExclusiveLock); - result->num_pages = RelationGetNumberOfBlocks(rel); + result->std.num_pages = RelationGetNumberOfBlocks(rel); if (needLock) UnlockRelationForExtension(rel, ExclusiveLock); diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c index cb82a38d90..ca0d6ec96d 100644 --- a/src/backend/access/hash/hash.c +++ b/src/backend/access/hash/hash.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.85 2006/02/11 17:14:08 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.86 2006/02/11 23:31:33 tgl Exp $ * * NOTES * This file contains only the public interface routines. @@ -517,6 +517,18 @@ hashbulkdelete(PG_FUNCTION_ARGS) cur_maxbucket = orig_maxbucket; loop_top: + + /* + * If we don't have anything to delete, skip the scan, and report the + * number of tuples shown in the metapage. (Unlike btree and gist, + * we can trust this number even for a partial index.) + */ + if (!callback_state) + { + cur_bucket = cur_maxbucket + 1; + num_index_tuples = local_metapage.hashm_ntuples; + } + while (cur_bucket <= cur_maxbucket) { BlockNumber bucket_blkno; diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index 6a681192ca..69c9ecb918 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.89 2006/02/11 17:14:08 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.90 2006/02/11 23:31:33 tgl Exp $ * * INTERFACE ROUTINES * index_open - open an index relation by relation OID @@ -685,6 +685,10 @@ index_getmulti(IndexScanDesc scan, * callback routine tells whether a given main-heap tuple is * to be deleted * + * if callback_state is NULL then there are no tuples to be deleted; + * index AM can choose to avoid work in this case, but must still + * follow the protocol of returning statistical info. + * * return value is an optional palloc'd struct of statistics * ---------------- */ diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index 4fb70302d7..e28faef141 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -12,7 +12,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.138 2006/02/11 17:14:08 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.139 2006/02/11 23:31:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -564,8 +564,22 @@ btbulkdelete(PG_FUNCTION_ARGS) * further to its right, which the indexscan will have no pin on.) We can * skip obtaining exclusive lock on empty pages though, since no indexscan * could be stopped on those. + * + * We can skip the scan entirely if there's nothing to delete (indicated + * by callback_state == NULL) and the index isn't partial. For a partial + * index we must scan in order to derive a trustworthy tuple count. */ - buf = _bt_get_endpoint(rel, 0, false); + if (callback_state || vac_is_partial_index(rel)) + { + buf = _bt_get_endpoint(rel, 0, false); + } + else + { + /* skip scan and set flag for btvacuumcleanup */ + buf = InvalidBuffer; + num_index_tuples = -1; + } + if (BufferIsValid(buf)) /* check for empty index */ { for (;;) @@ -836,6 +850,13 @@ btvacuumcleanup(PG_FUNCTION_ARGS) stats->pages_deleted = pages_deleted; stats->pages_free = nFreePages; + /* if btbulkdelete skipped the scan, use heap's tuple count */ + if (stats->num_index_tuples < 0) + { + Assert(info->num_heap_tuples >= 0); + stats->num_index_tuples = info->num_heap_tuples; + } + PG_RETURN_POINTER(stats); } diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index d60c433095..3153a0a559 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -13,7 +13,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.323 2006/02/11 17:14:09 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.324 2006/02/11 23:31:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -2955,6 +2955,7 @@ scan_index(Relation indrel, double num_tuples) /* Do post-VACUUM cleanup, even though we deleted nothing */ vcinfo.vacuum_full = true; vcinfo.message_level = elevel; + vcinfo.num_heap_tuples = num_tuples; stats = index_vacuum_cleanup(indrel, &vcinfo, stats); @@ -3022,6 +3023,7 @@ vacuum_index(VacPageList vacpagelist, Relation indrel, /* Do post-VACUUM cleanup */ vcinfo.vacuum_full = true; vcinfo.message_level = elevel; + vcinfo.num_heap_tuples = num_tuples + keep_tuples; stats = index_vacuum_cleanup(indrel, &vcinfo, stats); diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c index a65c269fc8..2c1ba51763 100644 --- a/src/backend/commands/vacuumlazy.c +++ b/src/backend/commands/vacuumlazy.c @@ -31,7 +31,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.65 2006/02/11 17:14:09 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.66 2006/02/11 23:31:34 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -625,6 +625,7 @@ lazy_scan_index(Relation indrel, LVRelStats *vacrelstats) /* Do post-VACUUM cleanup, even though we deleted nothing */ vcinfo.vacuum_full = false; vcinfo.message_level = elevel; + vcinfo.num_heap_tuples = vacrelstats->rel_tuples; stats = index_vacuum_cleanup(indrel, &vcinfo, stats); @@ -697,6 +698,9 @@ lazy_vacuum_index(Relation indrel, /* Do post-VACUUM cleanup */ vcinfo.vacuum_full = false; vcinfo.message_level = elevel; + /* We don't yet know rel_tuples, so pass -1 */ + /* index_bulk_delete can't have skipped scan anyway ... */ + vcinfo.num_heap_tuples = -1; stats = index_vacuum_cleanup(indrel, &vcinfo, stats); diff --git a/src/include/access/genam.h b/src/include/access/genam.h index 859c4e53b2..eace51db0e 100644 --- a/src/include/access/genam.h +++ b/src/include/access/genam.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.56 2006/02/11 17:14:09 momjian Exp $ + * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.57 2006/02/11 23:31:34 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -51,6 +51,7 @@ typedef struct IndexVacuumCleanupInfo { bool vacuum_full; /* VACUUM FULL (we have exclusive lock) */ int message_level; /* ereport level for progress messages */ + double num_heap_tuples; /* tuples remaining in heap */ } IndexVacuumCleanupInfo; /* Struct for heap-or-index scans of system tables */