Re: Running update in chunks?

On Mon, Jan 21, 2013 at 1:23 PM, Richard Huxton <dev(at)archonet(dot)com> wrote:
> 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.

I'd be curious to see results of the same "update" on a standard HDD
vs the SSD, and maybe on a more typical database deployment hardware
vs a macbook air.

--patrick