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[PATCH 8/8] Ignore correlation for new BRIN opclasses 2+ messages / 2 participants [nested] [flat]
* [PATCH 8/8] Ignore correlation for new BRIN opclasses @ 2020-09-12 13:07 Tomas Vondra <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Tomas Vondra @ 2020-09-12 13:07 UTC (permalink / raw) The new BRIN opclasses (bloom and minmax-multi) are less sensitive to poorly correlated data, so just assume the data is perfectly correlated during costing. Author: Tomas Vondra <[email protected]> Discussion: https://postgr.es/m/[email protected] --- src/backend/access/brin/brin_bloom.c | 1 + src/backend/access/brin/brin_minmax_multi.c | 1 + src/backend/utils/adt/selfuncs.c | 19 ++++++++++++++++++- src/include/access/brin_internal.h | 3 +++ 4 files changed, 23 insertions(+), 1 deletion(-) diff --git a/src/backend/access/brin/brin_bloom.c b/src/backend/access/brin/brin_bloom.c index c086e83236..22590b2351 100644 --- a/src/backend/access/brin/brin_bloom.c +++ b/src/backend/access/brin/brin_bloom.c @@ -412,6 +412,7 @@ brin_bloom_opcinfo(PG_FUNCTION_ARGS) result = palloc0(MAXALIGN(SizeofBrinOpcInfo(1)) + sizeof(BloomOpaque)); + result->oi_ignore_correlation = true; result->oi_nstored = 1; result->oi_regular_nulls = true; result->oi_opaque = (BloomOpaque *) diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c index d2dc38adc8..6b1dd1040c 100644 --- a/src/backend/access/brin/brin_minmax_multi.c +++ b/src/backend/access/brin/brin_minmax_multi.c @@ -1737,6 +1737,7 @@ brin_minmax_multi_opcinfo(PG_FUNCTION_ARGS) result = palloc0(MAXALIGN(SizeofBrinOpcInfo(1)) + sizeof(MinmaxMultiOpaque)); + result->oi_ignore_correlation = true; result->oi_nstored = 1; result->oi_regular_nulls = true; result->oi_opaque = (MinmaxMultiOpaque *) diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 52314d3aa1..0320d128f6 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -98,6 +98,7 @@ #include <math.h> #include "access/brin.h" +#include "access/brin_internal.h" #include "access/brin_page.h" #include "access/gin.h" #include "access/table.h" @@ -7352,7 +7353,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count, double minimalRanges; double estimatedRanges; double selec; - Relation indexRel; + Relation indexRel = NULL; + TupleDesc tupdesc = NULL; ListCell *l; VariableStatData vardata; @@ -7374,6 +7376,7 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count, */ indexRel = index_open(index->indexoid, NoLock); brinGetStats(indexRel, &statsData); + tupdesc = RelationGetDescr(indexRel); index_close(indexRel, NoLock); /* work out the actual number of ranges in the index */ @@ -7407,6 +7410,17 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count, { IndexClause *iclause = lfirst_node(IndexClause, l); AttrNumber attnum = index->indexkeys[iclause->indexcol]; + FmgrInfo *opcInfoFn; + BrinOpcInfo *opcInfo; + Form_pg_attribute attr = TupleDescAttr(tupdesc, iclause->indexcol); + bool ignore_correlation; + + opcInfoFn = index_getprocinfo(indexRel, iclause->indexcol + 1, BRIN_PROCNUM_OPCINFO); + + opcInfo = (BrinOpcInfo *) + DatumGetPointer(FunctionCall1(opcInfoFn, attr->atttypid)); + + ignore_correlation = opcInfo->oi_ignore_correlation; /* attempt to lookup stats in relation for this index column */ if (attnum != 0) @@ -7477,6 +7491,9 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count, if (sslot.nnumbers > 0) varCorrelation = Abs(sslot.numbers[0]); + if (ignore_correlation) + varCorrelation = 1.0; + if (varCorrelation > *indexCorrelation) *indexCorrelation = varCorrelation; diff --git a/src/include/access/brin_internal.h b/src/include/access/brin_internal.h index 89254b5766..063b703208 100644 --- a/src/include/access/brin_internal.h +++ b/src/include/access/brin_internal.h @@ -30,6 +30,9 @@ typedef struct BrinOpcInfo /* Regular processing of NULLs in BrinValues? */ bool oi_regular_nulls; + /* Ignore correlation during cost estimation */ + bool oi_ignore_correlation; + /* Opaque pointer for the opclass' private use */ void *oi_opaque; -- 2.26.2 --------------82D677E9F94AC7574E460205-- ^ permalink raw reply [nested|flat] 2+ messages in thread
* confusion about this commit "Revert "Skip redundant anti-wraparound vacuums"" @ 2023-06-05 03:30 jiye <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: jiye @ 2023-06-05 03:30 UTC (permalink / raw) To: [email protected] <[email protected]> hi, in our test enviroment, if one database's have major update operations, autovacuum does not work and cause major performance degradation. if found this issue may be resolved by revert this Skip redundant anti-wraparound vacuums ยท postgres/postgres@2aa6e33 (github.com) commit. after fetch some disccusion about this revert, i have some question as follow: 1. i understand that anti-wraparound and no-aggressive autovacuum will be skipped for shared catalog tables, but why this can trigger autovacuum does not work for others tables ? 2. "this could cause autovacuum to lock down", this lock down implict that autovacuum can make a dead lock problem ? 3. how to reproduce this lock down or autovacuum invalid issue, must be cluster enviroment ? so is there any body know these issuse or commits can give me some suggestion about my confusion. | | jiye | | [email protected] | ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2023-06-05 03:30 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2020-09-12 13:07 [PATCH 8/8] Ignore correlation for new BRIN opclasses Tomas Vondra <[email protected]> 2023-06-05 03:30 confusion about this commit "Revert "Skip redundant anti-wraparound vacuums"" jiye <[email protected]>
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