Re: [SQL] 7.3 analyze & vacuum analyze problem - Mailing list pgsql-performance

Josh wrote...
> Achilleus,
>
> > I am afraid it is not so simple.
> > What i (unsuccessfully) implied is that
> > dynacom=# VACUUM ANALYZE status ;
> > VACUUM
> > dynacom=# ANALYZE status ;
> > ANALYZE
> > dynacom=#
> >
> > [is enuf to damage the performance.]
>
> You're right, that is mysterious.   If you don't get a response from one of
> the major developers on this forum, I suggest that you post those EXPLAIN
> results to PGSQL-BUGS.

I had the same problem a while back.

http://archives.postgresql.org/pgsql-bugs/2002-08/msg00015.php
http://archives.postgresql.org/pgsql-bugs/2002-08/msg00018.php
http://archives.postgresql.org/pgsql-bugs/2002-08/msg00018.php

Short summary: Later in the thread Tom explained my problem as free
space not being evenly distributed across the table so ANALYZE's
sampling gave skewed results.  In my case, "pgstatuple" was a
good tool for diagnosing the problem, "vacuum full" fixed my table
and a much larger fsm_* would have probably prevented it.