Re: Index of a table is not used (in any case)

Doug McNaught wrote:

> Reiner Dassing <dassing@wettzell.ifag.de> writes:
>
> > Hello PostgreSQl Users!
> >
> > PostSQL V 7.1.1:
> >
> > I have defined a table and the necessary indices.
> > But the index is not used in every SELECT. (Therefore, the selects are
> > *very* slow, due to seq scan on
> > 20 million entries, which is a test setup up to now)
>
> Perennial first question: did you VACUUM ANALYZE?

Can there, or could there, be a notion of "rule based" optimization of
queries in PostgreSQL? The "not using index" problem is probably the most
common and most misunderstood problem.