Commit68ea2b7

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Reduce lock level for CREATE STATISTICS

In line with other lock reductions related to planning.Simon Riggs

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Lines changed: 2 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -923,7 +923,8 @@ ERROR: could not serialize access due to read/write dependencies among transact`
`923`	`923`
`924`	`924`	`<para>`
`925`	`925`	`Acquired by <command>VACUUM</command> (without <option>FULL</option>),`
`926`		`- <command>ANALYZE</>, <command>CREATE INDEX CONCURRENTLY</>, and`
	`926`	`+ <command>ANALYZE</>, <command>CREATE INDEX CONCURRENTLY</>,`
	`927`	`+ <command>CREATE STATISTICS</> and`
`927`	`928`	`<command>ALTER TABLE VALIDATE</command> and other`
`928`	`929`	`<command>ALTER TABLE</command> variants (for full details see`
`929`	`930`	`<xref linkend="SQL-ALTERTABLE">).`

Lines changed: 7 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -96,7 +96,13 @@ CreateStatistics(CreateStatsStmt *stmt)`
`96`	`96`	`errmsg("statistics \"%s\" already exist",namestr)));`
`97`	`97`	`}`
`98`	`98`
`99`		`-rel=heap_openrv(stmt->relation,AccessExclusiveLock);`
	`99`	`+/*`
	`100`	`+ * CREATE STATISTICS will influence future execution plans but does`
	`101`	`+ * not interfere with currently executing plans so it is safe to`
	`102`	`+ * take only ShareUpdateExclusiveLock on relation, conflicting with`
	`103`	`+ * ANALYZE and other DDL that sets statistical information.`
	`104`	`+ */`
	`105`	`+rel=heap_openrv(stmt->relation,ShareUpdateExclusiveLock);`
`100`	`106`	`relid=RelationGetRelid(rel);`
`101`	`107`
`102`	`108`	`if (rel->rd_rel->relkind!=RELKIND_RELATION&&`

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