Re: dump time increase by 1h with new kernel

Justin Pryzby <justinp@norchemlab.com> writes:
> 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.

Wouldn't be the first time the kernel guys broke something :-(
I think a complaint to your kernel supplier is in order.

In a coincidence, the first item in the changelog for this week's
Fedora kernel update is:

* Fri Sep 25 2009 Chuck Ebbert <cebbert@redhat.com> 2.6.30.8-64
- Fix serious CFQ performance regression.

This is surely not the exact same issue you are seeing, but it does
illustrate that performance regressions in the kernel aren't
unheard-of.

            regards, tom lane