Re: Re: Query not using index
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Chris Jones <chris@mt.sri.com>
Cc: ryan@paymentalliance.net, pgsql-general@postgresql.org
Date: 2001-05-10T21:43:15Z
Lists: pgsql-general
Chris Jones <chris@mt.sri.com> writes: >> Ah. You must have a few values that are far more frequent (like tens of >> thousands of occurrences?) and these are throwing off the planner's >> statistics. > I had a similar situation, where I had a lot of rows with 0's in > them. Changing those to NULLs worked wonders. Yes, if you have a lot of "dummy" values it's a good idea to represent them as NULLs rather than some arbitrarily-chosen regular data value. The planner does keep track of NULLs separately from everything else. regards, tom lane