Fix bug in freespace calculation in heap_multi_insert().

hlinnaka · hlinnaka · commit 6593c5b5dc39 · 2012-05-16T14:13:06.000+03:00
If the amount of freespace on page was less than the amount reserved by
fillfactor, the calculation would underflow.

This fixes bug #6643 reported by Tomonari Katsumata.
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
@@ -2159,7 +2159,7 @@ heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
 		{
 			HeapTuple	heaptup = heaptuples[ndone + nthispage];
 
-			if (PageGetHeapFreeSpace(page) - saveFreeSpace < MAXALIGN(heaptup->t_len))
+			if (PageGetHeapFreeSpace(page) < MAXALIGN(heaptup->t_len) + saveFreeSpace)
 				break;
 
 			RelationPutHeapTuple(relation, buffer, heaptup);

Original file line number	Diff line number	Diff line change
`@@ -2159,7 +2159,7 @@ heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,`
`2159`	`2159`	`{`
`2160`	`2160`	`HeapTuple heaptup = heaptuples[ndone + nthispage];`
`2161`	`2161`
`2162`		`- if (PageGetHeapFreeSpace(page) - saveFreeSpace < MAXALIGN(heaptup->t_len))`
	`2162`	`+ if (PageGetHeapFreeSpace(page) < MAXALIGN(heaptup->t_len) + saveFreeSpace)`
`2163`	`2163`	`break;`
`2164`	`2164`
`2165`	`2165`	`RelationPutHeapTuple(relation, buffer, heaptup);`