Path: utzoo!attcan!uunet!husc6!cmcl2!nrl-cmf!ames!zodiac!joyce!sri-unix!quintus!ok
From: ok@quintus.uucp (Richard A. O'Keefe)
Newsgroups: comp.databases
Subject: ensuring output has reached the disc (was Oracle wars)
Keywords: O_SYNC, fsync, SunOS 3.x
Message-ID: <179@quintus.UUCP>
Date: 20 Jul 88 21:23:13 GMT
References: <5165@dasys1.UUCP> <8208@ncoast.UUCP> <178@turbo.oracle.UUCP> <180@turbo.oracle.UUCP> <302@infmx.UUCP>
Sender: news@quintus.UUCP
Reply-To: ok@quintus.UUCP (Richard A. O'Keefe)
Organization: Quintus Computer Systems, Inc.
Lines: 34

In article <302@infmx.UUCP> aland@infmx.UUCP (Alan S. Denney @ Informix)
writes:
>The funniest thing is that they choose the Suns to run their benchmarks.
>Sun 3.X machines DO NOT SUPPORT synchronous writes anyway (no O_SYNC flag
>here, folks), so any claim that their benchmarks are hurt by "integrity
>issues" on these machines is BOGUS.  The only way to force i/o is to use
>raw devices; Oracle decries raw devices as being "complex" in their current
>ad.   (If my understanding of Sun 3.X synchronicity is wrong, I will post
>a followup and apology.  I confirmed this with a friend at Sun about a month 
>ago).  The current ads do *not* indicate that this integrity claim
>applies only to certain (e.g SVR2+) ports, that I recall.

I'm using SunOS 3.2.  A quick "grep" through /usr/include/*/*.h confirmed
the absence of an O_SYNC flag.  But "man -k sync" turned up
	fsync (2) - synchronize a file's in-core state with that on disk
and "man 2 fsync" says that fsync(fd)
     fsync moves all modified data and attributes of fd to a per-
     manent  storage  device:  all  in-core  modified  copies  of
     buffers for the associated file have been written to a  disk
     when  the  call  returns.   Note that this is different than
     sync(2) which schedules disk I/O for all files (as though an
     fsync had been done on all files) but returns before the I/O
     completes.

     fsync should be used by programs which require a file to  be
     in  a  known  state; for example, a program which contains a
     simple transaction facility might use it to ensure that  all
     modifications  to  a  file  or files caused by a transaction
     were recorded on disk.
    [Sun Release 3.2 Last Change: 16 July 1986]
				  ^^^^^^^^^^^^
This appears to claim that the changed information has actually been
written on the disc, not merely scheduled for writing.  What more do
you want, exactly?