Henk van Lingen <H.G.K.vanLingen@uu.nl> writes:
> On Thu, Sep 09, 2010 at 10:50:52AM -0400, Tom Lane wrote:
>>>> Well, there's your problem: the planner is off by a factor of about 500
>>>> on its estimate of the number of rows matching this query, and that's
>>>> what's causing it to pick the wrong plan. What you need to look into
>>>> is getting that estimate to be more in sync with reality. Probably
>>>> increasing the stats target for the message column would help.
> But how can I get sane estimates for syslog data? Some searchstrings will
> result in only a few hits, others in thousands of records or more.
That's what ANALYZE is for ...
regards, tom lane