Excerpts from Simon Riggs's message of jue mar 15 18:38:53 -0300 2012: > On Thu, Mar 15, 2012 at 2:26 AM, Robert Haas <robertmh...@gmail.com> wrote:
> > But that would only make sense if > > we thought that getting rid of the fsyncs would be more valuable than > > avoiding the blocking here, and I don't. > > You're right that the existing code could use some optimisation. > > I'm a little tired, but I can't see a reason to fsync this except at > checkpoint. Hang on. What fsyncs are we talking about? I don't see that the multixact code calls any fsync except that checkpoint and shutdown. > Also seeing that we issue 2 WAL records for each RI check. We issue > one during MultiXactIdCreate/MultiXactIdExpand and then immediately > afterwards issue a XLOG_HEAP_LOCK record. The comments on both show > that each thinks it is doing it for the same reason and is the only > place its being done. Alvaro, any ideas why that is. AFAIR the XLOG_HEAP_LOCK log entry only records the fact that the row is being locked by a multixact -- it doesn't record the contents (member xids) of said multixact, which is what the other log entry records. -- Álvaro Herrera <alvhe...@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
