Re: Running update in chunks?

On 21/01/13 20:09, Tim Uckun wrote:
> Just to close this up and give some guidance to future googlers...
Careful, future googlers.
> Conclusion. Updates on postgres are slow
Nope.

> (given the default
> postgresql.conf). I presume this is due to MVCC or the WAL or
> something and there are probably some things I can do to tweak the
> conf file to make them go faster but out of the box running an update
> on a table with lots of rows is going to cost you a lot.
Unlikely. Do you really think that a PostgreSQL installation typically
runs 100 times slower on updates than inserts and every other user has
just said "oh, that's ok then"? Or is it more likely that something
peculiar is broken on your setup.

> Removing the indexes doesn't help that much.
>
> Suggestion for the PG team. Deliver a more realistic postgres.conf by
> default. The default one seems to be aimed at ten year old PCs with
> very little RAM and disk space. At least deliver additional conf files
> for small, medium, large, huge setups.
--
Richard Huxton