On Thu, Jan 25, 2018 at 8:54 PM, Tsunakawa, Takayuki
<tsunakawa.takay@jp.fujitsu.com> wrote:
> Yes, that's pg_test_fsync output. Isn't pg_test_fsync the tool to determine the value for wal_sync_method? Is this
manualmisleading?
Hmm. I hadn't thought about it as misleading, but now that you
mention it, I'd say that it probably is. I suspect that there should
be a disclaimer saying that the fastest WAL sync method in terms of
ops/second is not necessarily the one that will deliver the best
database performance, and mention the issues around open_sync and
open_datasync specifically. But let's see what your testing shows;
I'm talking based on now-fairly-old experience with this and a passing
familiarity with the relevant source code.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
