Fix memory leak in GIN index scans.

tglsfdc · tglsfdc · commit f0e766bd7f77 · 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
@@ -281,6 +281,7 @@ 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
`@@ -281,6 +281,7 @@ collectMatchBitmap(GinBtreeData btree, GinBtreeStack stack,`
`281`	`281`	`ipd = ginReadTuple(btree->ginstate, scanEntry->attnum, itup, &nipd);`
`282`	`282`	`tbm_add_tuples(scanEntry->matchBitmap, ipd, nipd, false);`
`283`	`283`	`scanEntry->predictNumberResult += GinGetNPosting(itup);`
	`284`	`+ pfree(ipd);`
`284`	`285`	`}`
`285`	`286`
`286`	`287`	`/*`