Re: asynchronous i/o problem Oracle / Solaris (EXPERTS APPLY WITHIN)

From: Johne_uk <edgarj_at_tiscali.co.uk>
Date: 13 Sep 2005 16:02:43 -0700
Message-ID: <1126650594.643192.173850@z14g2000cwz.googlegroups.com>

AN EXTRACT FROM MY ORACLE SUPPORT TAR (after _lgwr_async_io = false was set)

---

set _lgwr_async_io = false to switch off async I/O only for the log writer.
disk_asynch_io would do it for the complete database.

You should also speak with SUN. I know that they had some problems on SUN version
before 8 with async I/O.
TRACE FILE

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>From the lgwr trace file I see lines like
...
21227/9: lwp_cond_wait(0xFEAA1FA0, 0xFEAA1FB0, 0x00000000) = 0 21227/9: pwrite64(26211, "\0\007 0\0\001 v !BAF7B1".., 1024, 191488) = 1024
21227/9: kaio(AIONOTIFY, 0) = 0
21227/1: kaio(AIOWAIT, 0xFFBFE5D8)
.
I think this shows that the lgwr does not use async I/O. Otherwise we would see
kaio(AIOREAD;...) and lwp_create() calls in truss.

I also see pwrite64 calls, this means we write to disk. Received on Tue Sep 13 2005 - 18:02:43 CDT