Do not allow Unique nodes to be scanned backwards. The code claimed that it
authorTom Lane <tgl@sss.pgh.pa.us>
Tue, 5 Aug 2008 21:28:42 +0000 (21:28 +0000)
committerTom Lane <tgl@sss.pgh.pa.us>
Tue, 5 Aug 2008 21:28:42 +0000 (21:28 +0000)
commitaab9979c5c8fed679e8f1240aae8cfd4e6432100
treefcbe6b370fe6fd0aa215c538d7652210cb6ec426
parenta1b631b35349e077eadd6c00908abd8bf49244bb
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
src/backend/executor/nodeUnique.c