Kiriakos Tsourapas wrote:
> When the problem appears, vacuuming is not helping. I ran vacuum
> manually and the problem was still there. Only full vacuum worked.
>
> As far as I have understood, autovacuuming is NOT doing FULL
> vacuum. So, messing around with its values should not help me in
> any way.
That is absolutely wrong. A regular vacuum, or autovacuum not
hopelessly crippled by your configuration, will prevent the table
bloat which is slowing things down. It does not, however, fix bloat
once it has occurred; a normal vacuum then is like closing the barn
door after the horse has already bolted -- it would have prevented
the problem if done in time, but it won't cure it.
A VACUUM FULL in version 8.4 will fix bloat of the table's heap, but
will tend to bloat the indexes. You should probably fix your
autovcauum configuration (making it *at least* as aggressive as the
default), CLUSTER the affected table(s) to fix both table and index
bloat, and schedule an upgrade to the latest bug fix release of major
version 8.4.
http://www.postgresql.org/support/versioning/
Minor releases (where the version number only changes after the
second dot) only contain fixes for bugs and security problems, and
never require a dump/load or pg_upgrade run. If you insist on
running with known bugs, you can expect problems.
-Kevin