On Sun, Mar 11, 2012 at 12:55 PM, Robert Haas <robertmh...@gmail.com> wrote: > I've finally been able to run some more tests of the effect of > adjusting wal_buffers to values higher than 16MB. I ran the test on > the 16 core (x 4 hw threads/core) IBM POWER7 machine, with my usual > configuration settings: > > shared_buffers = 8GB > maintenance_work_mem = 1GB > synchronous_commit = off > checkpoint_segments = 300 > checkpoint_timeout = 15min > checkpoint_completion_target = 0.9 > wal_writer_delay = 20ms > > I ran three 30-minute tests at scale factor 300 with wal_buffers set > at various values from 16MB up to 160MB, in multiples of 16MB, using > pgbench with 32 clients and 32 threads in each case. The short > version is that 32MB seems to be significantly better than 16MB, by > about 1000 tps, and after that it gets murky; full results are below.
Currently the max of wal_buffers is 16MB (i.e., the size of one WAL file) when it's set to -1. Thanks to your result, we should increase the max to 32MB? Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
