On Thu, Apr 7, 2016 at 6:12 PM, Peter Geoghegan <p...@heroku.com> wrote:
> I think that there is a good argument in favor of this patch that you > may have failed to make yourself, which is: it limits bloat in a way > that's analogous to how RecentGlobalDataXmin can do so for logical > decoding (i.e. where wal_level = logical, and RecentGlobalXmin and > RecentGlobalDataXmin could actually differ). Therefore, it benefits to > a significant degree from the testing that Andres did to make sure > logical decoding doesn't cause excessive bloat when RecentGlobalXmin > is pinned to make historic MVCC catalog snapshots work (he did so at > my insistence at the time; pruning turned out to be very important for > many common workloads, and Andres got that right). I can't really > imagine a way that what you have here could be any less effective than > what Andres did for logical decoding. This is reassuring, since that > mechanism has to be pretty well battle-hardened by now. Interesting. I had not noticed that relationship. Anyway, pushed as two patches -- the no-op patch to create the "forced choice" on whether to do the test at each BufferGetPage point, and the actual feature. Sadly, I forgot to include the reviewer information when writing the commit messages. :-( -- Kevin Grittner EDB: 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
