Re: our friend the win32 system timer.
От | Bruce Momjian |
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Тема | Re: our friend the win32 system timer. |
Дата | |
Msg-id | 200408161944.i7GJiRG01217@candle.pha.pa.us обсуждение исходный текст |
Ответ на | our friend the win32 system timer. ("Merlin Moncure" <merlin.moncure@rcsonline.com>) |
Список | pgsql-hackers-win32 |
Merlin Moncure wrote: > Depending on how you look at it, this may be a semi-serious problem in > win32. pg uses the C library time routines to calculate elapsed time > and supply values. > > Unfortunately, this value is only updated for each timeslice allocated > to the thread. The resolution of this timer is about 10 ms... > > This means that a table with a timestamp column defaulted to now() and a > unique constraint on that column will have a very high chance of > constraint violations. This might happen when reading in values from a > script, and it works fine on Linux. > > A side issue is that psql analyze timings are not useful below 10 ms. > Should the win32 high performance counter, QueryPerformanceCounter, be > introduced? This seems like a very minor limitation to me. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
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