Re: Is autovaccum lazy?

2009/12/5 A B <gentosaker@gmail.com>:
> Hello.
> I just ran these commands
>
> select pg_database_size('cdb');
> vacuum full;
> select pg_database_size('cdb');
>
> and got
>
> 315250448
> ----
> 90669060
>
> So I guess that the vaccuum full command released space that was not
> used any more.  A week ago I guess the same commands would have
> resulted in quite similar numbers. Is there some way of finding out
> what the autovaccum have done? I'm having a hard time beliving that
> the autovaccuum has done it's job properly since there were so much
> "wasted" space, or did it just not find it worth the effort to release
> the unused space?
> Any  thoughts about this?

Vacuum full clears up more space, than plain vacuum... however, that
does not mean its "better", in fact, its not advised:
http://wiki.postgresql.org/wiki/VACUUM_FULL#When_.28not.29_to_use_VACUUM_FULL

>
> I might have a similar system I could run these commands on. Any
> advice on other commands to run then to find out more?
>
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