On Nov 16, 2010, at 4:05 PM, Mladen Gogala wrote: > Josh Berkus wrote: >> On 11/16/10 12:39 PM, Greg Smith wrote: >> >>> I want to next go through and replicate some of the actual database >>> level tests before giving a full opinion on whether this data proves >>> it's worth changing the wal_sync_method detection. So far I'm torn >>> between whether that's the right approach, or if we should just increase >>> the default value for wal_buffers to something more reasonable. >>> >> >> We'd love to, but wal_buffers uses sysV shmem. >> >> > Speaking of the SYSV SHMEM, is it possible to use huge pages? RHEL 6 and friends have transparent hugepage support. I'm not sure if they yet transparently do it for SYSV SHMEM, but they do for most everything else. Sequential traversal of a process heap is several times faster with hugepages. Unfortunately, postgres doesn't organize its blocks in its shared_mem to be sequential for a relation. So it might not matter much. > > -- > > Mladen Gogala > Sr. Oracle DBA > 1500 Broadway > New York, NY 10036 > (212) 329-5251 > http://www.vmsinfo.com > The Leader in Integrated Media Intelligence Solutions > > > > > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
