Re: 7.0.3(nofsync) vs 7.1
От | Bruce Momjian |
---|---|
Тема | Re: 7.0.3(nofsync) vs 7.1 |
Дата | |
Msg-id | 200012110144.UAA15129@candle.pha.pa.us обсуждение исходный текст |
Ответ на | 7.0.3(nofsync) vs 7.1 ("Mikheev, Vadim" <vmikheev@SECTORBASE.COM>) |
Список | pgsql-hackers |
[ Charset ISO-8859-1 unsupported, converting... ] > I've run tests (with 50 .. 250 simult users) for some PG project > of my company. 7.1 was 3 times faster than 7.0.3 (fsync) but near > 3 times slower than 7.0.3 (nofsync). It was not the best day in > my life - WAL looked like big bottleneck -:( > > But finally I've realized that this test makes ~3 FK insertions > ... and FK insert means SELECT FOR UPDATE ... and this could > reduce # of commits per fsync. > > So, I've run simple test (below) to check this. Seems that 7.1 > is faster than 7.0.3 (nofsync), and that SELECT FOR UPDATE in RI > triggers is quite bad for performance. > > Please take this into account when comparing 7.1 with 7.0.3. > Also, we should add new TODO item: implement dirty reads > and use them in RI triggers. Added: * Implement dirty reads and use them in RI triggers -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026
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