| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Brent Dearth <brent(dot)dearth(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Horrible CREATE DATABASE Performance in High Sierra |
| Date: | 2017-10-02 19:54:43 |
| Message-ID: | 13746.1506974083@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Andres Freund <andres(at)anarazel(dot)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
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