Re: BUG #1186: Broken Index?

On Fri, Jul 02, 2004 at 04:50:07 -0300,
  PostgreSQL Bugs List <pgsql-bugs@postgresql.org> wrote:
>
> The following bug has been logged online:

This doesn't appear to be a bug at this point. It sounds like you have
a self induced performance problem, so I am moving the discussion to
pgsql-performance.

>
> Bug reference:      1186
> Logged by:          Gosen, Hitoshi
>
> Email address:      mic-gosen@ns.inter-mic.co.jp
>
> PostgreSQL version: 7.4
>
> Operating system:   linux 2.4.18
>
> Description:        Broken Index?
>
> Details:
>
> Hello All,
> We are using PostgreSQL 7.4.2 for our website that handles over 200,000
> transactions a day.
> About a month ago, the responses from the SELECT queries on the database
> became terribly slow.
> We tried to anaylze the cause of the problem, searching throught the system
> logs and all, but nothing appeared to be out of the ordinary.
>
> What we did to resolve this was to dump the database, delete the database,
> recreate the database, and finally restore it. After that, things were back
> to normal.
>
> From the above experience, we were able to hypothesize that the fault of the
> slow responses was not from a broken data or hardware failures, but from a
> broken index, since we were able to recover 100% of the data on the same
> machine.
>
> Today, the same problem occured, and the same actions are going to be taken
> to temporary resolve it.
>
> Final note: we will also experiment with the  'vacuum full' command to see
> if it counters this problem.

It sounds like you aren't properly vacuuming your database. It is possible
that you need a higher FSM setting or to vacuum more frequently.