Re: Simple postgresql.conf wizard

On Wed, 2008-12-03 at 13:30 -0500, Robert Haas wrote:
> > Looks like I need to add Python 2.5+Linux to my testing set. I did not
> > expect that the UNIX distributions of Python 2.5 would ship with wintypes.py
> > at all. I think I can fix this on the spot though. On line 40, you'll find
> > this bit:
> >
> > except ImportError:
> >
> > Change that to the following:
> >
> > except ImportError,ValueError:
>
> That didn't work, same error message.
>
> > And it should pass that point. If it doesn't, you can try the completely
> > general:
> >
> > except:
>
> That worked.
>
> The settings that this initially spit out (I guess it defaults to
> "mixed" mode) didn't look too sane to me, because as discussed
> elsewhere on this thread 50 is not a reasonable value for
> default_statistics_target for my installation. It also wanted to set
> constraint_exclusion to on, which I'm pretty confident is useless.
>
> Then I tried "-T web" and got what seemed like a more reasonable set
> of values. But I wasn't sure I needed that many connections, so I
> added "-c 150" to see how much difference that made. Kaboom!
>
> $ ./pgtune -i ~postgres/data/postgresql.conf -T web -c 150
> Traceback (most recent call last):
> File "./pgtune", line 463, in <module>
> wizardTune(config,options,settings)
> File "./pgtune", line 403, in wizardTune
> 'web':mem/con, 'oltp':mem/con,'dw':mem/con/2,
> TypeError: unsupported operand type(s) for /: 'int' and 'str'
>
> I'm not sure what "mixed" mode is supposed to be, but based on what
> I've seen so far, I'm a skeptical of the idea that encouraging people
> to raise default_statistics_target to 50 and turn on
> constraint_exclusion is reasonable.

Why?

> I'm also a bit surprised that
> there doesn't seem to be anything here that depends on the size of the
> database, even order-of-magnitude. It seems like the right value for
> checkpoint_segments, at least, might depend on that.

What does checkpoint_segments have to do with the size of the database?

Joshua D. Drake

>
> ...Robert
>
--
PostgreSQL
Consulting, Development, Support, Training
503-667-4564 - http://www.commandprompt.com/
The PostgreSQL Company, serving since 1997