From 27048980f503da22dcd289ec8342b7021c8e73e6 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 22 Jul 2014 13:30:01 -0400 Subject: [PATCH] Re-enable error for "SELECT ... OFFSET -1". The executor has thrown errors for negative OFFSET values since 8.4 (see commit bfce56eea45b1369b7bb2150a150d1ac109f5073), but in a moment of brain fade I taught the planner that OFFSET with a constant negative value was a no-op (commit 1a1832eb085e5bca198735e5d0e766a3cb61b8fc). Reinstate the former behavior by only discarding OFFSET with a value of exactly 0. In passing, adjust a planner comment that referenced the ancient behavior. Back-patch to 9.3 where the mistake was introduced. --- src/backend/optimizer/plan/planner.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index f2c9c99b7f..e1480cda24 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -2335,7 +2335,7 @@ preprocess_limit(PlannerInfo *root, double tuple_fraction, { *offset_est = DatumGetInt64(((Const *) est)->constvalue); if (*offset_est < 0) - *offset_est = 0; /* less than 0 is same as 0 */ + *offset_est = 0; /* treat as not present */ } } else @@ -2496,9 +2496,8 @@ limit_needed(Query *parse) { int64 offset = DatumGetInt64(((Const *) node)->constvalue); - /* Executor would treat less-than-zero same as zero */ - if (offset > 0) - return true; /* OFFSET with a positive value */ + if (offset != 0) + return true; /* OFFSET with a nonzero value */ } } else -- 2.40.0