Commit1c1ecd5

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Improve planner estimates for size of tuple hash tables.

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Lines changed: 2 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.199 2006/03/05 15:58:29 momjian Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.200 2006/06/28 20:04:38 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -1298,7 +1298,7 @@ choose_hashed_grouping(PlannerInfo *root, double tuple_fraction,`
`1298`	`1298`	`}`
`1299`	`1299`
`1300`	`1300`	`/* Estimate per-hash-entry space at tuple width... */`
`1301`		`-hashentrysize=cheapest_path_width;`
	`1301`	`+hashentrysize=MAXALIGN(cheapest_path_width)+MAXALIGN(sizeof(MinimalTupleData));`
`1302`	`1302`	`/* plus space for pass-by-ref transition values... */`
`1303`	`1303`	`hashentrysize+=agg_counts->transitionSpace;`
`1304`	`1304`	`/* plus the per-hash-entry overhead */`

Lines changed: 6 additions & 4 deletions

Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@`
`7`	`7`	`* Portions Copyright (c) 1994, Regents of the University of California`
`8`	`8`	`*`
`9`	`9`	`* IDENTIFICATION`
`10`		`- * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.107 2006/05/03 00:24:56 tgl Exp $`
	`10`	`+ * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.108 2006/06/28 20:04:38 tgl Exp $`
`11`	`11`	`*`
`12`	`12`	`*-------------------------------------------------------------------------`
`13`	`13`	`*/`
`@@ -585,11 +585,13 @@ subplan_is_hashable(SubLink slink, SubPlan node)`
`585`	`585`	`return false;`
`586`	`586`
`587`	`587`	`/*`
`588`		`- * The estimated size of the subquery result must fit in work_mem. (XXX`
`589`		`- * what about hashtable overhead?)`
	`588`	`+ * The estimated size of the subquery result must fit in work_mem.`
	`589`	`+ * (Note: we use sizeof(HeapTupleHeaderData) here even though the tuples`
	`590`	`+ * will actually be stored as MinimalTuples; this provides some fudge`
	`591`	`+ * factor for hashtable overhead.)`
`590`	`592`	`*/`
`591`	`593`	`subquery_size=node->plan->plan_rows*`
`592`		`-(MAXALIGN(node->plan->plan_width)+MAXALIGN(sizeof(HeapTupleData)));`
	`594`	`+(MAXALIGN(node->plan->plan_width)+MAXALIGN(sizeof(HeapTupleHeaderData)));`
`593`	`595`	`if (subquery_size>work_mem*1024L)`
`594`	`596`	`return false;`
`595`	`597`

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