Re: We need to log aborted autovacuums

On Sun, 2011-01-16 at 12:50 -0800, Josh Berkus wrote:
> On 1/16/11 11:19 AM, Simon Riggs wrote:
> > I would prefer it if we had a settable lock timeout, as suggested many
> > moons ago. When that was discussed before it was said there was no
> > difference between a statement timeout and a lock timeout, but I think
> > there clearly is, this case being just one example.
>
> Whatever happend to lock timeouts, anyway? We even had some patches
> floating around for 9.0 and they disappeared.
>
> However, we'd want a separate lock timeout for autovac, of course. I'm
> not at all keen on a *statement* timeout on autovacuum; as long as
> autovacuum is doing work, I don't want to cancel it.

> Also, WTF would we
> set it to?

> Going the statement timeout route seems like a way to create a LOT of
> extra work, troubleshooting, getting it wrong, and releasing patch
> updates. Please let's just create a lock timeout.

I agree with you, but if we want it *this* release, on top of all the
other features we have queued, then I suggest we compromise. If you hold
out for more feature, you may get less.

Statement timeout = 2 * (100ms + autovacuum_vacuum_cost_delay) *
tablesize/(autovacuum_vacuum_cost_limit / vacuum_cost_page_dirty)

--
Simon Riggs http://www.2ndQuadrant.com/books/
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