Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> An alternative solution would be to lower the vacuum delay settings before
> starting the truncating phase, but this doesn't work very well in autovacuum
> due to the autobalancing code (which can cause other processes to change our
> cost delay settings). This case could be considered in the balancing code, but
> it is simpler this way.
I don't think autovacuum has a problem --- if someone requests a
conflicting lock, autovac will get kicked off, no? The OP's problem
comes from doing a manual vacuum. Perhaps "don't do that" is a good
enough answer.
regards, tom lane