From: Klaus P. Pieper <kpi6288@gmail.com>
To: 'Tom Lane' <tgl@sss.pgh.pa.us>
Cc: pgsql-admin@postgresql.org
Subject: Re: pgbench Windows outperforms Debian in Write tests while Debian is faster in SELECT only tests
Date: Mon, 29 May 2017 21:59:43 +0200
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> Von: Tom Lane
> Gesendet: Montag, 29. Mai 2017 18:17
>
> OK, so open_datasync and fdatasync are nonfunctional on Windows, which is
> unsurprising. The other cases are evidently doing *something*, but the
amount
> of overhead is variable from one sync method to another, which is likewise
> unsurprising. The whole reason why we have these options at all is that
some
> systems handle some of them better than others. In this case, I think the
> relevant conclusion is that correct configuration for Debian is to use
> open_datasync or fdatasync, while correct configuration for Windows is to
use
> fsync or fsync_writethrough, and when you compare those two
configurations,
> yes Windows is slower.
Excellent answer, thanks.
Correct me if I'm wrong: I understand that synchronous_commit = off in
combination with fdatasync (Debian) or fsync_writethrough (Windows) is
"safe" (for regular interactive desktop applications).
These options gave the following results:
Windows Debian
40 clients READ/WRITE 5400 7400
1 client READ/WRITE 400 390
Single client READ/WRITE tests are on now the same level. In the multi
client test, Debian is performing significantly better than Windows.
>
> If you're a paranoid sort you would want to do plug-pull testing to ensure
that
> your selected setting actually does prevent data corruption during a
system
> crash.
That's certainly an option before we take this into production.
Regards Klaus
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To: pgsql-admin@postgresql.org
Cc: kpi6288@gmail.com, tgl@sss.pgh.pa.us
Subject: Re: pgbench Windows outperforms Debian in Write tests while Debian is faster in SELECT only tests
In-Reply-To: <006401d2d8b6$1e889240$5b99b6c0$@gmail.com>
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