From 29e818d7cc99c045940ce24b1ac4def597f7e2d6 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 5 Aug 2008 21:28:48 +0000 Subject: [PATCH] Do not allow Unique nodes to be scanned backwards. The code claimed that it would work, but in fact it didn't return the same rows when moving backwards as when moving forwards. This would have no visible effect in a DISTINCT query (at least assuming the column datatypes use a strong definition of equality), but it gave entirely wrong answers for DISTINCT ON queries. --- src/backend/executor/execAmi.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c index da2791876e..b42bfc9f75 100644 --- a/src/backend/executor/execAmi.c +++ b/src/backend/executor/execAmi.c @@ -383,9 +383,6 @@ ExecSupportsBackwardScan(Plan *node) case T_Sort: return true; - case T_Unique: - return ExecSupportsBackwardScan(outerPlan(node)); - case T_Limit: return ExecSupportsBackwardScan(outerPlan(node)); -- 2.39.5