On Thu, Aug 30, 2012 at 8:17 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Robert Haas <robertmhaas@xxxxxxxxx> writes: >> On Thu, Aug 30, 2012 at 4:51 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: >>> Bruce Momjian <bruce@xxxxxxxxxx> writes: >>>> On Thu, May 31, 2012 at 09:20:43AM +0900, Tatsuo Ishii wrote: >>>>> Ok, I modified the part of pg_dump where tremendous number of LOCK >>>>> TABLE are issued. I replace them with single LOCK TABLE with multiple >>>>> tables. With 100k tables LOCK statements took 13 minutes in total, now >>>>> it only takes 3 seconds. Comments? > >>>> Was this applied? > >>> No, we fixed the server side instead. > >> But only for 9.2, right? So people running back branches are still screwed. > > Yeah, but they're screwed anyway, because there are a bunch of O(N^2) > behaviors involved here, not all of which are masked by what Tatsuo-san > suggested. All of the other ones that I know of were associated with pg_dump itself, and since it is recommended to run the newer version of pg_dump against the older version of the server, no back patching would be necessary to get the benefits of those particular fixes. > Six months or a year from now, we might have enough confidence in that > batch of 9.2 fixes to back-port them en masse. Don't want to do it > today though. What would be the recommendation for people trying to upgrade, but who can't get their data out in a reasonable window? Putting Tatsuo-san's change into a future pg_dump might be more conservative than back-porting the server's Lock Table change to the server version they are trying to get rid of. Cheers, Jeff -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
