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* [PATCH 9/9] 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 b54b963f87..af87737ae0 100644
--- a/src/backend/access/brin/brin_bloom.c
+++ b/src/backend/access/brin/brin_bloom.c
@@ -410,6 +410,7 @@ 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 c77c207e94..28a6a85b5a 100644
--- a/src/backend/access/brin/brin_minmax_multi.c
+++ b/src/backend/access/brin/brin_minmax_multi.c
@@ -1798,6 +1798,7 @@ 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 47ca4ddbb5..bf40f9ce32 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 fdaff42722..5fbf8cf9c7 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
--------------22A4B241170149838D4D1F8F--
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: improving user.c error messages
@ 2023-01-27 18:13 Alvaro Herrera <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: Alvaro Herrera @ 2023-01-27 18:13 UTC (permalink / raw)
To: Tom Lane <[email protected]>; +Cc: Robert Haas <[email protected]>; Peter Eisentraut <[email protected]>; Nathan Bossart <[email protected]>; pgsql-hackers
On 2023-Jan-27, Tom Lane wrote:
> Good point. My vote is for standardizing on *not* mentioning it.
> Error messages should say "you need privilege X". That is not
> the place to go into all the ways you could hold privilege X
> (one of which is being superuser).
+1
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
"El sabio habla porque tiene algo que decir;
el tonto, porque tiene que decir algo" (Platon).
^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2023-01-27 18:13 UTC | newest]
Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed)
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2020-09-12 13:07 [PATCH 9/9] Ignore correlation for new BRIN opclasses Tomas Vondra <[email protected]>
2023-01-27 18:13 Re: improving user.c error messages Alvaro Herrera <[email protected]>
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