From 564851f3d0450c604732ecf468ce46457d36d989 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Fri, 4 Oct 2024 14:29:47 -0400 Subject: [PATCH v1 1/2] Add relallfrozen to pg_class Add relallfrozen, an estimate of the number of pages marked all-frozen in the visibility map. pg_class already has relallvisible, an estimate of the number of pages in the relation marked all-visible in the visibility map. This is used primarily for planning. relallfrozen, however, is useful for estimating the outstanding number of all-visible but not all-frozen pages in the relation for the purposes of scheduling manual VACUUMs and tuning vacuum freeze parameters. In the future, this field could be used to trigger more frequent vacuums on insert-focused workloads with significant volume of frozen data. --- doc/src/sgml/catalogs.sgml | 15 ++++++++++++++ src/backend/access/heap/vacuumlazy.c | 17 ++++++++++++---- src/backend/catalog/heap.c | 2 ++ src/backend/catalog/index.c | 27 +++++++++++++++++-------- src/backend/commands/analyze.c | 12 +++++------ src/backend/commands/cluster.c | 5 +++++ src/backend/commands/vacuum.c | 6 ++++++ src/backend/statistics/relation_stats.c | 9 +++++++++ src/backend/utils/cache/relcache.c | 2 ++ src/include/catalog/pg_class.h | 3 +++ src/include/commands/vacuum.h | 1 + 11 files changed, 81 insertions(+), 18 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 964c819a02..174ef29ed6 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -2066,6 +2066,21 @@ SCRAM-SHA-256$<iteration count>:&l + + + relallfrozen int4 + + + Number of pages that are marked all-frozen in the table's + visibility map. This is only an estimate used for triggering autovacuums. + It is updated by VACUUM, + ANALYZE, and a few DDL commands such as + CREATE INDEX. + Every all-frozen page must also be marked all-visible. + + + + reltoastrelid oid diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index d82aa3d489..dff4cd08a9 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -303,7 +303,8 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, minmulti_updated; BlockNumber orig_rel_pages, new_rel_pages, - new_rel_allvisible; + new_rel_allvisible, + new_rel_allfrozen; PGRUsage ru0; TimestampTz starttime = 0; PgStat_Counter startreadtime = 0, @@ -558,10 +559,17 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, * pg_class.relpages to */ new_rel_pages = vacrel->rel_pages; /* After possible rel truncation */ - visibilitymap_count(rel, &new_rel_allvisible, NULL); + visibilitymap_count(rel, &new_rel_allvisible, &new_rel_allfrozen); if (new_rel_allvisible > new_rel_pages) new_rel_allvisible = new_rel_pages; + /* + * Every block marked all-frozen in the VM must also be marked + * all-visible. + */ + if (new_rel_allfrozen > new_rel_allvisible) + new_rel_allfrozen = new_rel_allvisible; + /* * Now actually update rel's pg_class entry. * @@ -570,7 +578,8 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, * scan every page that isn't skipped using the visibility map. */ vac_update_relstats(rel, new_rel_pages, vacrel->new_live_tuples, - new_rel_allvisible, vacrel->nindexes > 0, + new_rel_allvisible, new_rel_allfrozen, + vacrel->nindexes > 0, vacrel->NewRelfrozenXid, vacrel->NewRelminMxid, &frozenxid_updated, &minmulti_updated, false); @@ -3100,7 +3109,7 @@ update_relstats_all_indexes(LVRelState *vacrel) vac_update_relstats(indrel, istat->num_pages, istat->num_index_tuples, - 0, + 0, 0, false, InvalidTransactionId, InvalidMultiXactId, diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c index 0078a12f26..d150d2b9a7 100644 --- a/src/backend/catalog/heap.c +++ b/src/backend/catalog/heap.c @@ -920,6 +920,7 @@ InsertPgClassTuple(Relation pg_class_desc, values[Anum_pg_class_relpages - 1] = Int32GetDatum(rd_rel->relpages); values[Anum_pg_class_reltuples - 1] = Float4GetDatum(rd_rel->reltuples); values[Anum_pg_class_relallvisible - 1] = Int32GetDatum(rd_rel->relallvisible); + values[Anum_pg_class_relallfrozen - 1] = Int32GetDatum(rd_rel->relallfrozen); values[Anum_pg_class_reltoastrelid - 1] = ObjectIdGetDatum(rd_rel->reltoastrelid); values[Anum_pg_class_relhasindex - 1] = BoolGetDatum(rd_rel->relhasindex); values[Anum_pg_class_relisshared - 1] = BoolGetDatum(rd_rel->relisshared); @@ -990,6 +991,7 @@ AddNewRelationTuple(Relation pg_class_desc, new_rel_reltup->relpages = 0; new_rel_reltup->reltuples = -1; new_rel_reltup->relallvisible = 0; + new_rel_reltup->relallfrozen = 0; /* Sequences always have a known size */ if (relkind == RELKIND_SEQUENCE) diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 12822d0b14..2386009a1d 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -2795,8 +2795,8 @@ FormIndexDatum(IndexInfo *indexInfo, * hasindex: set relhasindex to this value * reltuples: if >= 0, set reltuples to this value; else no change * - * If reltuples >= 0, relpages and relallvisible are also updated (using - * RelationGetNumberOfBlocks() and visibilitymap_count()). + * If reltuples >= 0, relpages, relallvisible, and relallfrozen are also + * updated (using RelationGetNumberOfBlocks() and visibilitymap_count()). * * NOTE: an important side-effect of this operation is that an SI invalidation * message is sent out to all backends --- including me --- causing relcache @@ -2841,8 +2841,8 @@ index_update_stats(Relation rel, * transaction could still fail before committing. Setting relhasindex * true is safe even if there are no indexes (VACUUM will eventually fix * it). And of course the new relpages and reltuples counts are correct - * regardless. However, we don't want to change relpages (or - * relallvisible) if the caller isn't providing an updated reltuples + * regardless. However, we don't want to change relpages (or relallvisible + * and relallfrozen) if the caller isn't providing an updated reltuples * count, because that would bollix the reltuples/relpages ratio which is * what's really important. */ @@ -2888,12 +2888,18 @@ index_update_stats(Relation rel, if (reltuples >= 0 && !IsBinaryUpgrade) { BlockNumber relpages = RelationGetNumberOfBlocks(rel); - BlockNumber relallvisible; + BlockNumber relallvisible = 0; + BlockNumber relallfrozen = 0; + /* don't bother for indexes */ if (rd_rel->relkind != RELKIND_INDEX) - visibilitymap_count(rel, &relallvisible, NULL); - else /* don't bother for indexes */ - relallvisible = 0; + { + visibilitymap_count(rel, &relallvisible, &relallfrozen); + + /* Every all-frozen page must also be set all-visible in the VM */ + if (relallfrozen > relallvisible) + relallfrozen = relallvisible; + } if (rd_rel->relpages != (int32) relpages) { @@ -2910,6 +2916,11 @@ index_update_stats(Relation rel, rd_rel->relallvisible = (int32) relallvisible; dirty = true; } + if (rd_rel->relallfrozen != (int32) relallfrozen) + { + rd_rel->relallfrozen = (int32) relallfrozen; + dirty = true; + } } /* diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c index 38fb4c3ef2..0928592272 100644 --- a/src/backend/commands/analyze.c +++ b/src/backend/commands/analyze.c @@ -630,12 +630,11 @@ do_analyze_rel(Relation onerel, VacuumParams *params, */ if (!inh) { - BlockNumber relallvisible; + BlockNumber relallvisible = 0; + BlockNumber relallfrozen = 0; if (RELKIND_HAS_STORAGE(onerel->rd_rel->relkind)) - visibilitymap_count(onerel, &relallvisible, NULL); - else - relallvisible = 0; + visibilitymap_count(onerel, &relallvisible, &relallfrozen); /* * Update pg_class for table relation. CCI first, in case acquirefunc @@ -646,6 +645,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params, relpages, totalrows, relallvisible, + relallfrozen, hasindex, InvalidTransactionId, InvalidMultiXactId, @@ -662,7 +662,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params, vac_update_relstats(Irel[ind], RelationGetNumberOfBlocks(Irel[ind]), totalindexrows, - 0, + 0, 0, false, InvalidTransactionId, InvalidMultiXactId, @@ -678,7 +678,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params, */ CommandCounterIncrement(); vac_update_relstats(onerel, -1, totalrows, - 0, hasindex, InvalidTransactionId, + 0, 0, hasindex, InvalidTransactionId, InvalidMultiXactId, NULL, NULL, in_outer_xact); diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index 78f96789b0..4376355066 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -1224,6 +1224,7 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class, int32 swap_pages; float4 swap_tuples; int32 swap_allvisible; + int32 swap_allfrozen; swap_pages = relform1->relpages; relform1->relpages = relform2->relpages; @@ -1236,6 +1237,10 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class, swap_allvisible = relform1->relallvisible; relform1->relallvisible = relform2->relallvisible; relform2->relallvisible = swap_allvisible; + + swap_allfrozen = relform1->relallfrozen; + relform1->relallfrozen = relform2->relallfrozen; + relform2->relallfrozen = swap_allfrozen; } /* diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index ac8f5d9c25..7ed4df509c 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -1410,6 +1410,7 @@ void vac_update_relstats(Relation relation, BlockNumber num_pages, double num_tuples, BlockNumber num_all_visible_pages, + BlockNumber num_all_frozen_pages, bool hasindex, TransactionId frozenxid, MultiXactId minmulti, bool *frozenxid_updated, bool *minmulti_updated, @@ -1459,6 +1460,11 @@ vac_update_relstats(Relation relation, pgcform->relallvisible = (int32) num_all_visible_pages; dirty = true; } + if (pgcform->relallfrozen != (int32) num_all_frozen_pages) + { + pgcform->relallfrozen = (int32) num_all_frozen_pages; + dirty = true; + } /* Apply DDL updates, but not inside an outer transaction (see above) */ diff --git a/src/backend/statistics/relation_stats.c b/src/backend/statistics/relation_stats.c index 1a6d1640c3..1b1f02546f 100644 --- a/src/backend/statistics/relation_stats.c +++ b/src/backend/statistics/relation_stats.c @@ -160,6 +160,15 @@ relation_statistics_update(FunctionCallInfo fcinfo, int elevel) replaces[ncols] = Anum_pg_class_relallvisible; values[ncols] = Int32GetDatum(relallvisible); ncols++; + + /* + * If we are modifying relallvisible manually, it is not clear + * what relallfrozen value would make sense. Therefore, set it to + * NULL. It will be updated the next time these fields are + * updated. + */ + replaces[ncols] = Anum_pg_class_relallfrozen; + nulls[ncols] = true; } } diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c index c326f687eb..4bd9e10310 100644 --- a/src/backend/utils/cache/relcache.c +++ b/src/backend/utils/cache/relcache.c @@ -1936,6 +1936,7 @@ formrdesc(const char *relationName, Oid relationReltype, relation->rd_rel->relpages = 0; relation->rd_rel->reltuples = -1; relation->rd_rel->relallvisible = 0; + relation->rd_rel->relallfrozen = 0; relation->rd_rel->relkind = RELKIND_RELATION; relation->rd_rel->relnatts = (int16) natts; relation->rd_rel->relam = HEAP_TABLE_AM_OID; @@ -3931,6 +3932,7 @@ RelationSetNewRelfilenumber(Relation relation, char persistence) classform->relpages = 0; /* it's empty until further notice */ classform->reltuples = -1; classform->relallvisible = 0; + classform->relallfrozen = 0; } classform->relfrozenxid = freezeXid; classform->relminmxid = minmulti; diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h index 0fc2c093b0..659ee68620 100644 --- a/src/include/catalog/pg_class.h +++ b/src/include/catalog/pg_class.h @@ -68,6 +68,9 @@ CATALOG(pg_class,1259,RelationRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(83,Relat /* # of all-visible blocks (not always up-to-date) */ int32 relallvisible BKI_DEFAULT(0); + /* # of all-frozen blocks (not always up-to-date) */ + int32 relallfrozen BKI_DEFAULT(0); + /* OID of toast table; 0 if none */ Oid reltoastrelid BKI_DEFAULT(0) BKI_LOOKUP_OPT(pg_class); diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h index 759f9a87d3..c3fd2919e6 100644 --- a/src/include/commands/vacuum.h +++ b/src/include/commands/vacuum.h @@ -329,6 +329,7 @@ extern void vac_update_relstats(Relation relation, BlockNumber num_pages, double num_tuples, BlockNumber num_all_visible_pages, + BlockNumber num_all_frozen_pages, bool hasindex, TransactionId frozenxid, MultiXactId minmulti, -- 2.45.2