On 2/1/16 6:13 PM, Andres Freund wrote:
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.

The only reason I can see for the 1 hour limit is to try and prevent footguns. I think that's a valid goal, but there should be a way to over-ride it. And if we don't want that kind of protection then I'd say just yank the upper limit.

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, ...).

It would be interesting if someone had a large-ish 9.4 or 9.5 install that they could test recovery timing on. My suspicion is that as long as FPWs are on that you'd generally end up limited by how fast you could read WAL unless you exceeded the FS cache. (I'm assuming a BBU and that the FS and controller will do a nice job of ordering writes optimally so that you'll get performance similar to reads when it's time to fsync.)
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com

Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:

Reply via email to