Re: dump time increase by 1h with new kernel

On Fri, 2 Oct 2009, Justin Pryzby wrote:

> When we upgraded from linux-2.6.24 to linux-2.6.27, our pg_dump
> duration increased by 20% from 5 hours to 6.

Why 2.6.27 of all versions?  It's one of the versions I skipped altogether
as looking like a mess, after CFS broke everything in 2.6.23 I went right
from 2.6.22 to 2.6.28 before I found things usable again.  The first thing
you're going to hear if you try to report this in kernel land is "is it
still slow on 2.6.[last stable|head]?".

If you can try both kernel versions, the other thing you really should do
is collect data from "vmstat 1" during the pg_dump period.  It would help
narrow what area is slower.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD