Re: Horrible CREATE DATABASE Performance in High Sierra

Andres Freund <andres@anarazel.de> writes:
> On 2017-10-02 15:42:25 -0400, Tom Lane wrote:
>> I experimented with this further by seeing whether the msync() code path
>> is of any value on Sierra either.  The answer seems to be "no": cloning
>> a scale-1000 pgbench database takes about 17-18 seconds on my Sierra
>> laptop using unmodified HEAD, but if I dike out the msync() logic then
>> it takes 16-17 seconds.  Both numbers jump around a little, but using
>> msync is strictly worse.

> Well, that's only measuring one type of workload. Could you run a normal
> pgbench with -P1 or so for 2-3 checkpoint cycles and see how big the
> latency differences are?

Should I expect there to be any difference at all?  We don't enable
*_flush_after by default on non-Linux platforms.

			regards, tom lane