| From: | Xu Yifeng <jamexu(at)telekbird(dot)com(dot)cn> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Alfred Perlstein <bright(at)wintelcom(dot)net>, "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>, Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, Peter Eisentraut <peter_e(at)gmx(dot)net>, <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re[2]: Allowing WAL fsync to be done via O_SYNC |
| Date: | 2001-03-16 06:26:00 |
| Message-ID: | 7420422776.20010316142600@telekbird.com.cn |
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| Thread: | |
| Lists: | pgsql-hackers |
Hello Tom,
Friday, March 16, 2001, 6:54:22 AM, you wrote:
TL> Alfred Perlstein <bright(at)wintelcom(dot)net> writes:
>> How many files need to be fsync'd?
TL> Only one.
>> If it's more than one, what might work is using mmap() to map the
>> files in adjacent areas, then calling msync() on the entire range,
>> this would allow you to batch fsync the data.
TL> Interesting thought, but mmap to a prespecified address is most
TL> definitely not portable, whether or not you want to assume that
TL> plain mmap is ...
TL> regards, tom lane
Could anyone consider fork a syncer process to sync data to disk ?
build a shared sync queue, when a daemon process want to do sync after
write() is called, just put a sync request to the queue. this can release
process from blocked on writing as soon as possible. multipile sync
request for one file can be merged when the request is been inserting to
the queue.
--
Regards,
Xu Yifeng
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