"Maxim Boguk" <Maxim.Boguk@gmail.com> writes:
> In my case vacuum tried to truncate last 10-15GB from 100Gb relation, and
> each time (3) it was cost 10+ minutes of service downtime (because that
> table was completely locked).
> Is that correct behaviour? Are here any way to speedup that process or at
> least allow read-only queries during that time?
Use autovacuum --- if there's something that wants to access the table,
autovac will get kicked off the lock. (Of course, the table may never
get truncated then, but maybe you don't care.)
regards, tom lane