Re: [PERFORM] More detail on settings for pgavd?

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Josh Berkus <josh(at)agliodbs(dot)com> writes:
> > BTW, do we have any provisions to avoid overlapping vacuums? That is, to
> > prevent a second vacuum on a table if an earlier one is still running?
>
> Yes, VACUUM takes a lock that prevents another VACUUM on the same table.

The second vacuum waits for the lock to become available. If the situation got
really bad there could end up being a growing queue of vacuums waiting.

I'm not sure how likely this is as the subsequent vacuums appear to finish
quite quickly though. But then the largest table I have to play with fits
entirely in memory.

--
greg