Do not allow Unique nodes to be scanned backwards. The code claimed that it
commit19b5172fbf57941c1b28223ad9b5372097fec4d0
authortgl <tgl>
Tue, 5 Aug 2008 21:28:29 +0000 (5 21:28 +0000)
committertgl <tgl>
Tue, 5 Aug 2008 21:28:29 +0000 (5 21:28 +0000)
tree1beb5c1edd06a12b534877578794a982e23f974e
parent33d8e7a1a0359315f6caff1b8ebc2b705e31d941
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