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 1755268211e16a42774eb2242f835cd40ca69258..7e0b98211f4e8f18defb385cea574536396b2c1b 100644 (file)
--- a/src/backend/executor/nodeLimit.c
+++ b/src/backend/executor/nodeLimit.c
@@ -125,7 +125,7 @@ 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;