On 22 Mar, Tom Lane wrote: > [EMAIL PROTECTED] writes: >> I could certainly do some testing if you want to see how DBT-2 does. >> Just tell me what to do. ;) > > Just do some runs that are identical except for the wal_sync_method > setting. Note that this should not have any impact on SELECT > performance, only insert/update/delete performance.
Ok, here are the results I have from my 4-way xeon system, a 14 disk volume for the log and a 52 disk volume for everything else: http://developer.osdl.org/markw/pgsql/wal_sync_method.html 7.5devel-200403222 wal_sync_method metric default (fdatasync) 1935.28 fsync 1613.92 # ./test_fsync -f /opt/pgdb/dbt2/pg_xlog/test.out Simple write timing: write 0.018787 Compare fsync times on write() and non-write() descriptor: (If the times are similar, fsync() can sync data written on a different descriptor.) write, fsync, close 13.057781 write, close, fsync 13.311313 Compare one o_sync write to two: one 16k o_sync write 6.515122 two 8k o_sync writes 12.455124 Compare file sync methods with one 8k write: (o_dsync unavailable) open o_sync, write 6.270724 write, fdatasync 13.275225 write, fsync, 13.359847 Compare file sync methods with 2 8k writes: (o_dsync unavailable) open o_sync, write 12.479563 write, fdatasync 13.651709 write, fsync, 14.000240 ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]