Avoid integer overflow when LIMIT + OFFSET >= 2^63.

hlinnaka · hlinnaka · commit 89df948ec266 · 2011-08-02T10:47:17.000+03:00
This fixes bug #6139 reported by Hitoshi Harada.
diff --git a/src/backend/executor/nodeLimit.c b/src/backend/executor/nodeLimit.c
@@ -127,7 +127,7 @@ ExecLimit(LimitState *node)
 				 * the state machine state to record having done so.
 				 */
 				if (!node->noCount &&
-					node->position >= node->offset + node->count)
+					node->position - node->offset >= node->count)
 				{
 					node->lstate = LIMIT_WINDOWEND;
 					return NULL;

Original file line number	Diff line number	Diff line change
`@@ -127,7 +127,7 @@ ExecLimit(LimitState *node)`
`127`	`127`	`* the state machine state to record having done so.`
`128`	`128`	`*/`
`129`	`129`	`if (!node->noCount &&`
`130`		`- node->position >= node->offset + node->count)`
	`130`	`+ node->position - node->offset >= node->count)`
`131`	`131`	`{`
`132`	`132`	`node->lstate = LIMIT_WINDOWEND;`
`133`	`133`	`return NULL;`