Re: autovacuum and transaction id wraparound

On Fri, Mar 9, 2012 at 12:15 AM, pawel_kukawski <kukismen(at)gmail(dot)com> wrote:
> Hi Jens,
>
> Thanks for answer. One more question:
>
> Can the manual VACUUM operate on database where there are long lasting
> transactions?
>
> In other words, do I need to restart the server or kill long lasting
> transactions in order to allow manual VACUUM to clear old XIDs?

Long running transactions block both manual and automatic vacuums.

The only difference between manual and automatic vacuuming is the
costing parameters, which don't have to be different. I.e. if you set
the autovacuum_* costs to the same as the vacuum_* costs no diff in
operation.

The issue you might run into is the one Tom mentioned, that if you've
got a long running autovacuum that started with the older less
aggressive settings you might need to kill it (you can use
pg_cancel_backend() or sigint from the command like) to get it to
start back up with the new costs.