From: Klaus P. Pieper <kpi6288@gmail.com>
To: pgsql-admin@postgresql.org
Subject: pgbench Windows outperforms Debian in Write tests while Debian is faster in SELECT only tests
Date: Mon, 29 May 2017 09:42:53 +0200
Message-ID: <028501d2d84f$2f1ea840$8d5bf8c0$@gmail.com> (raw)
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I did a quick comparison between Windows and Linux (Debian) in the following
environment:
Server E3-1245 with 40GB RAM running Hyper-V 2016
Hyper-V uses 2 SSDs as RAID 1
For the tests both freshly installed:
1. Windows 10 test image from modern.ie
2. Debian 8.8 with Xfce desktop
3. Current PostgreSQL 9.6.3 (x64)
Setup was pretty much standard on both machines. Only shared_buffers was
increased to 4000MB.
Test preparation with a scale factor of 200:
pgbench -i -s 200 -U postgres pgbench
All tests were carried out repeatedly with different -T settings to
eliminate "warming up" effects. pgbench running on the same machine as the
database server.
These are TPS numbers (the table was written in monospace font e.g.
Consolas):
Windows Debian Test statement
40 clients SELECT only 47000 76000 pgbench -c 40 -j 10 -T 150
-U postgres -S -P 5 pgbench
1 client SELECT only 3300 18000 pgbench -c 40 -j 10 -T 150
-U postgres -P 5 pgbench
40 clients READ/WRITE 2000 2000 pgbench -U postgres -S -P 5
pgbench
1 client READ WRITE 370 150 pgbench -U postgres -P 5
pgbench
Mounting the file system with barriers=0 gives much better results on the
Debian system (better than the Windows system). But since this machine does
not have a battery buffered disk adapter, that wouldn't be an option for a
production system.
I'm in particular concerned about the disadvantage in the single client
WRITE scenario running Debian. How can Windows outperform Debian by a factor
of 2?
Is there anything I could do to improve the Debian write performance?
Thank you
Klaus
BTW: My original intention was to analyze the difference between standard
installation and initdb --data-checksums. Results were similar on both
systems.
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Subject: Re: pgbench Windows outperforms Debian in Write tests while Debian is faster in SELECT only tests
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