Re: autovacuum strategy / parameters

On Sat, May 1, 2010 at 1:17 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> On Sat, May 1, 2010 at 1:08 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Sat, May 1, 2010 at 12:13 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
>>> On Fri, Apr 30, 2010 at 4:50 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
>>>> Which is the opposite of my experience; currently we have several
>>>> clients who have issues which required more-frequent analyzes on
>>>> specific tables.   Before 8.4, vacuuming more frequently, especially on
>>>> large tables, was very costly; vacuum takes a lot of I/O and CPU.  Even
>>>> with 8.4 it's not something you want to increase without thinking about
>>>> the tradeoff
>>>
>>> Actually I would think that statement would be be that before 8.3
>>> vacuum was much more expensive.  The changes to vacuum for 8.4 mostly
>>> had to do with moving FSM to disk, making seldom vacuumed tables
>>> easier to keep track of, and making autovac work better in the
>>> presence of long running transactions.  The ability to tune IO load
>>> etc was basically unchanged in 8.4.
>>
>> What about http://www.postgresql.org/docs/8.4/static/storage-vm.html ?
>
> That really only has an effect no tables that aren't updated very
> often.  Unless you've got a whole bunch of those, it's not that big of
> a deal.

sigh, s/ no / on /

Anyway, my real point was that the big improvements that made vacuum
so much better came in 8.3, with HOT updates and multi-threaded vacuum
(that might have shown up in 8.2 even) 8.3 was a huge improvement and
compelling upgrade from 8.1 for me.