I could not duplicate this on any identical database, but thought I would report it here, just for completeness. I've tried reindexing, vacuuming, etc. Explain plans all look normal.
Version is 8.1.3
\d bigtable
...
"bigtable_status_partial" btree (status) WHERE status::text <>
'shipped'::text
greg=> select (select count(*) from bigtable where status = 'shipped')
+ (select count(*) from bigtable where status <> 'shipped')
UNION select count(*) from bigtable;
?column?
----------
1185213
1600569
greg=> drop index bigtable_status_partial;
greg=> select (select count(*) from bigtable where status = 'shipped')
+ (select count(*) from bigtable where status <> 'shipped')
UNION select count(*) from bigtable;
?column?
----------
1185213
(1 row)
--
Greg Sabino Mullane [EMAIL PROTECTED]
End Point Corporation
PGP Key: 0x14964AC8 200608290003
http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8
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