Re: Raising the checkpoint_timeout limit

On Tue, Feb 02, 2016 at 01:13:20AM +0100, Andres Freund wrote:
> is there any reason for the rather arbitrary and low checkpoint_timeout
> limit?

Not that I know, and it is inconvenient.

> I'm not sure what'd actually be a good upper limit. I'd be inclined to
> even go to as high as a week or so. A lot of our settings have
> upper/lower limits that aren't a good idea in general.

In general, I favor having limits reflect fundamental system limitations
rather than paternalism. Therefore, I would allow INT_MAX (68 years).

> I'm also wondering if it'd not make sense to raise the default timeout
> to 15min or so. The upper ceiling for that really is recovery time, and
> that has really shrunk rather drastically due to faster cpus and
> architectural improvements in postgres (bgwriter, separate
> checkpointer/bgwriter, restartpoints, ...).

Have those recovery improvements outpaced the increases in max recovery time
from higher core counts generating more WAL per minute?

nm