On Sat, Aug 31, 2013 at 2:34 PM, Andres Freund <and...@2ndquadrant.com> wrote: > After some thinking I don't think any solution primarily based on > holding page level locks across other index operations is going to scale > ok.
I'd like to chime in with a large +1 for this sentiment and pretty much everything else Andres said further downthread. The operations across which you're proposing to hold buffer locks seem at least an order of magnitude too complex to get away with something like that. Concurrent readers will block in a non-interruptible wait if they try to access a buffer, and that's a situation that will be intolerable if, for example, it can persist across a disk I/O. And I don't see any way to avoid that. One possible alternative to inserting promises into the index pages themselves might be to use some kind of heavyweight lock. The way that SIREAD locks work is not entirely dissimilar to what's needed here, I think. Of course, the performance implications of checking for lots of extra locks during inserts could be pretty bad, so you'd probably need some way of avoiding that in common cases, which I don't know exactly how to do, but maybe there's a way. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
