Re: Strange slow database

David Mitchell <david.mitchell@telogis.com> writes:
> Recently our databases started to experience a significant slowdown.
> Queries that were taking 500ms now take up to 20 seconds. An insert can
> take 150ms or more. This is strange since we are still hitting indexes
> and we vacuum regularly. Here is the description of our system:

Have you checked to see whether you are encountering table or index
bloat?  Your vacuuming policy doesn't sound unreasonable on its face,
but there's no substitute for actually looking at physical file sizes
when you aren't sure what's wrong.  Try doing a pg_dump and reload into
a virgin database, then compare file sizes with the original
table-by-table to see if anything is drastically out of line.
Don't forget to look at the system catalogs too.

            regards, tom lane