Re: auto-vacuum questions

On Thu, May 8, 2008 at 12:10 PM, John Gateley <gateley(at)jriver(dot)com> wrote:
>
> On Thu, 8 May 2008 10:58:47 -0700
> Alan Hodgson <ahodgson(at)simkin(dot)ca> wrote:
>
> > On Thursday 08 May 2008, John Gateley <gateley(at)jriver(dot)com> wrote:
> > > But the new database, mydbtest, always has slow queries.
> > > I run an analyze and they speed up.
> >
> > Do the query plans actually change, or are you just seeing caching effects
> > from running the analyze?
>
> The query plans actually change. I'm pretty sure that the auto-vacuum
> wasn't happening, I'm going to test this tomorrow morning with
> a fresh copy.

Well, if you're testing on different values, then it should change
based on changes in selectivity and range. But if the where clause is
the same, the query plan probably isn't changing between runs.