Re: queries are fast after dump->restore but slow again after some days dispite vacuum

On 07/19/2012 11:13 AM, Felix Scheicher wrote:
> Andrew Dunstan <andrew <at> dunslane.net> writes:
>
>> Try running CLUSTER on the relevant tables and see if it makes a
>> difference. If it does you might want to look into using pg_reorg
>> periodically.
>
> That worked like a charm! Many thanks. But how comes, the queries are also fast
> after a restore without the cluster?
>



There is probably a lot of unused space in your table. CLUSTER rewrites
a fresh copy, as do restore and pg_reorg.

You might also want to try changing the settings on the table so it gets
much more aggressively auto-vacuumed, so that dead space is made
available much more quickly, and the table has less chance to get bloated.

cheers

andrew