Greg Smith wrote:
> Bruce Momjian wrote:
> > Is there a value to this test_fsync test?
> >
> > Compare open_sync with different sizes:
> > (This is designed to compare the cost of one large
> > sync'ed write and two smaller sync'ed writes.)
> > open_sync 16k write 242.563 ops/sec
> > 2 open_sync 8k writes 752.752 ops/sec
> >
> > It compares the cost of doing larger vs. two smaller open_sync writes.
> >
>
> Might be some value for determining things like what the optimal WAL
> block size to use is. All these tests are kind of hard to use
> effectively still, I'm not sure if it's time to start trimming tests yet
> until we've made more progress on interpreting results first.
FYI, I beefed up the testing for this in test_fsync:
Compare open_sync with different write sizes:(This is designed to compare the cost of writing 16kin different write
open_syncsizes.) 1 16k open_sync write 723.824 ops/sec 2 8k open_sync writes
347.979ops/sec 4 4k open_sync writes 215.114 ops/sec 8 2k open_sync writes
174.613ops/sec 16 1k open_sync writes 87.496 ops/sec
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ It's impossible for everything to be true. +
