Re: checkpoint_segments 32 megs?

On Wed, Jul 13, 2005 at 12:53:57PM -0700, Joshua D. Drake wrote:

> Tom made mention earlier this week that upping the checkpoint segments
> might be a bad idea because we are committing someone to 32 megs per
> segment. I thought it odd at the time but I figured it was an 8.1 thing.
>
> As I review the 8.1dev postgresql.conf the checkpoint_segments option
> still states 16 megs per segment is that correct?

The point is that in general, the 16 MiB figure is correct, but in
pathological cases there can be up to two WAL segments on disk per
checkpoint_segment, so 32 MiB. I don't remember the exact details but I
think it was about generating lots of WAL traffic during checkpoint,
which would lead to additional files being created while the older ones
can't be removed or recycled yet.

--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"Estoy de acuerdo contigo en que la verdad absoluta no existe...
El problema es que la mentira sí existe y tu estás mintiendo" (G. Lama)