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

This fixes bug #6139 reported by Hitoshi Harada.

diff --git a/src/backend/executor/nodeLimit.c b/src/backend/executor/nodeLimit.c
index 7557e735b68119b53de4384046925b99600a6b11..2dd472f9bc25b03511912b12ad19f96237fc52e2 100644 (file)
--- a/src/backend/executor/nodeLimit.c
+++ b/src/backend/executor/nodeLimit.c
@@ -120,7 +120,7 @@ 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;