Fix memory leak in GIN index scans.

tglsfdc · tglsfdc · commit 0479eccdcf0d · 2016-04-15T00:02:26.000-04:00
The code had a query-lifespan memory leak when encountering GIN entries that have posting lists (rather than posting trees, ie, there are a relatively small number of heap tuples containing this index key value). With a suitable data distribution this could add up to a lot of leakage. Problem seems to have been introduced by commit 36a35c5, so back-patch to 9.4. Julien Rouhaud
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
@@ -278,6 +278,7 @@ collectMatchBitmap(GinBtreeData *btree, GinBtreeStack *stack,
 			ipd = ginReadTuple(btree->ginstate, scanEntry->attnum, itup, &nipd);
 			tbm_add_tuples(scanEntry->matchBitmap, ipd, nipd, false);
 			scanEntry->predictNumberResult += GinGetNPosting(itup);
+			pfree(ipd);
 		}
 
 		/*

Original file line number	Diff line number	Diff line change
`@@ -278,6 +278,7 @@ collectMatchBitmap(GinBtreeData btree, GinBtreeStack stack,`
`278`	`278`	`ipd = ginReadTuple(btree->ginstate, scanEntry->attnum, itup, &nipd);`
`279`	`279`	`tbm_add_tuples(scanEntry->matchBitmap, ipd, nipd, false);`
`280`	`280`	`scanEntry->predictNumberResult += GinGetNPosting(itup);`
	`281`	`+ pfree(ipd);`
`281`	`282`	`}`
`282`	`283`
`283`	`284`	`/*`