On Friday 17 July 2009 11:12:41 Jan-Ivar Mellingen wrote: > One of our customers discovered that by replacing <>TRUE with =FALSE in > a query of a table containing 750.000 records reduced the query time > from about 12 seconds to about 60 milliseconds!
> This is a dramatical difference, but I cannot understand why. In my head > "<>TRUE" should behave exactly the same as "=FALSE". This looks like a > bug to me, or am I overlooking something? The planner just isn't that smart. The boolean type is a special case where <> some_value implies = some_other_value, but this doesn't generalize well to other data types. And the planner doesn't have a whole lot of data type specific knowledge. I think a better index definition might actually be on alarm_status, with a partial index predicate on logg_avsluttet = false. -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
