Fix MERGE tuple count with DO NOTHING

alvherre · alvherre · commit 6ff5aa129933 · 2022-11-17T18:56:11.000+01:00
Reporting tuples for which nothing is done is useless and goes against the documented behavior, so don't do it. Backpatch to 15. Reported by: Luca Ferrari Discussion: https://postgr.es/m/CAKoxK+42MmACUh6s8XzASQKizbzrtOGA6G1UjzCP75NcXHsiNw@mail.gmail.com
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
@@ -2799,7 +2799,7 @@ ExecMergeMatched(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
 		{
 			case TM_Ok:
 				/* all good; perform final actions */
-				if (canSetTag)
+				if (canSetTag && commandType != CMD_NOTHING)
 					(estate->es_processed)++;
 
 				break;

Original file line number	Diff line number	Diff line change
`@@ -2799,7 +2799,7 @@ ExecMergeMatched(ModifyTableContext context, ResultRelInfo resultRelInfo,`
`2799`	`2799`	`{`
`2800`	`2800`	`case TM_Ok:`
`2801`	`2801`	`/* all good; perform final actions */`
`2802`		`- if (canSetTag)`
	`2802`	`+ if (canSetTag && commandType != CMD_NOTHING)`
`2803`	`2803`	`(estate->es_processed)++;`
`2804`	`2804`
`2805`	`2805`	`break;`