Fix freeing old values in index_store_float8_orderby_distances()

akorotkov · akorotkov · commit 8c8a267201be · 2019-09-20T01:19:08.000+03:00
6cae9d2 has added an error in freeing old values in index_store_float8_orderby_distances() function. It looks for old value in scan->xs_orderbynulls[i] after setting a new value there. This commit fixes that. Also it removes short-circuit in handling distances == NULL situation. Now distances == NULL will be treated the same way as array with all null distances. That is, previous values will be freed if any. Reported-by: Tom Lane, Nikita Glukhov Discussion: https://postgr.es/m/CAPpHfdu2wcoAVAm3Ek66rP%3Duo_C-D84%2B%2Buf1VEcbyi_caBXWCA%40mail.gmail.com Discussion: https://postgr.es/m/426580d3-a668-b9d1-7b8e-f74d1a6524e0%40postgrespro.ru Backpatch-through: 12
diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c
@@ -852,37 +852,29 @@ index_store_float8_orderby_distances(IndexScanDesc scan, Oid *orderByTypes,
 {
 	int			i;
 
-	scan->xs_recheckorderby = recheckOrderBy;
-
-	if (!distances)
-	{
-		Assert(!scan->xs_recheckorderby);
-
-		for (i = 0; i < scan->numberOfOrderBys; i++)
-		{
-			scan->xs_orderbyvals[i] = (Datum) 0;
-			scan->xs_orderbynulls[i] = true;
-		}
+	Assert(distances || !recheckOrderBy);
 
-		return;
-	}
+	scan->xs_recheckorderby = recheckOrderBy;
 
 	for (i = 0; i < scan->numberOfOrderBys; i++)
 	{
-		scan->xs_orderbynulls[i] = distances[i].isnull;
-
-		if (scan->xs_orderbynulls[i])
-			scan->xs_orderbyvals[i] = (Datum) 0;
-
 		if (orderByTypes[i] == FLOAT8OID)
 		{
 #ifndef USE_FLOAT8_BYVAL
 			/* must free any old value to avoid memory leakage */
 			if (!scan->xs_orderbynulls[i])
 				pfree(DatumGetPointer(scan->xs_orderbyvals[i]));
 #endif
-			if (!scan->xs_orderbynulls[i])
+			if (distances && !distances[i].isnull)
+			{
 				scan->xs_orderbyvals[i] = Float8GetDatum(distances[i].value);
+				scan->xs_orderbynulls[i] = false;
+			}
+			else
+			{
+				scan->xs_orderbyvals[i] = (Datum) 0;
+				scan->xs_orderbynulls[i] = true;
+			}
 		}
 		else if (orderByTypes[i] == FLOAT4OID)
 		{
@@ -892,8 +884,16 @@ index_store_float8_orderby_distances(IndexScanDesc scan, Oid *orderByTypes,
 			if (!scan->xs_orderbynulls[i])
 				pfree(DatumGetPointer(scan->xs_orderbyvals[i]));
 #endif
-			if (!scan->xs_orderbynulls[i])
+			if (distances && !distances[i].isnull)
+			{
 				scan->xs_orderbyvals[i] = Float4GetDatum((float4) distances[i].value);
+				scan->xs_orderbynulls[i] = false;
+			}
+			else
+			{
+				scan->xs_orderbyvals[i] = (Datum) 0;
+				scan->xs_orderbynulls[i] = true;
+			}
 		}
 		else
 		{
