On Tue, Nov 5, 2019 at 1:42 AM Stephen Frost <sfr...@snowman.net> wrote: > * Andres Freund (and...@anarazel.de) wrote: > > > That's quite doable independent of parallelism, as we don't have tables > > or indexes spanning more than one tablespace. True, you could then make > > the processing of an individual vacuum faster by allowing to utilize > > multiple tablespace budgets at the same time. > > Yes, it's possible to do independent of parallelism, but what I was > trying to get at above is that it might not be worth the effort. When > it comes to parallel vacuum though, I'm not sure that you can just punt > on this question since you'll naturally end up spanning multiple > tablespaces concurrently, at least if the heap+indexes are spread across > multiple tablespaces and you're operating against more than one of those > relations at a time >
Each parallel worker operates on a separate index. It might be worth exploring per-tablespace vacuum throttling, but that should not be a requirement for the currently proposed patch. As per feedback in this thread, it seems that for now, it is better, if we can allow a parallel vacuum only when I/O throttling is not enabled. We can later extend it based on feedback from the field once the feature starts getting used. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
