Fix handling of volatile expressions in COPY FROM ... WHERE

tvondra · tvondra · commit 4a8283d0ec5a · 2019-01-22T23:11:17.000+01:00
The checking for calls to volatile functions in the COPY FROM ... WHERE expression was treating all WHERE clauses as if containing such calls. While that does not produce incorrect results, this disables batching which may result in significant performance regression. Discussion: https://www.postgresql.org/message-id/flat/CALAY4q_DdpWDuB5-Zyi-oTtO2uSk8pmy+dupiRe3AvAc++1imA@mail.gmail.com
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
@@ -2612,8 +2612,7 @@ CopyFrom(CopyState cstate)
 		 */
 		insertMethod = CIM_SINGLE;
 	}
-	else if (cstate->whereClause != NULL ||
-			 contain_volatile_functions(cstate->whereClause))
+	else if (contain_volatile_functions(cstate->whereClause))
 	{
 		/*
 		 * Can't support multi-inserts if there are any volatile funcation

Original file line number	Diff line number	Diff line change
`@@ -2612,8 +2612,7 @@ CopyFrom(CopyState cstate)`
`2612`	`2612`	`*/`
`2613`	`2613`	`insertMethod = CIM_SINGLE;`
`2614`	`2614`	`}`
`2615`		`- else if (cstate->whereClause != NULL \|\|`
`2616`		`- contain_volatile_functions(cstate->whereClause))`
	`2615`	`+ else if (contain_volatile_functions(cstate->whereClause))`
`2617`	`2616`	`{`
`2618`	`2617`	`/*`
`2619`	`2618`	`* Can't support multi-inserts if there are any volatile funcation`