Re: Filesystem device O/S Buffering

From: Art S. Kagel <kagel_at_bloomberg.net>
Date: Thu, 10 Dec 1998 11:38:34 -0500
Message-ID: <366FF90A.6EB2@bloomberg.net>

Piotr Kolodziej wrote:

> >With Solaris filesystems, data can be stored in the disk cache for up to
> >20 seconds before being flushed. Does Oracle use some special O/S call to
> >force the flush? Or does it bypass the O/S disk cache somehow?

> As I remember a simple example of flushing OS buffers is fflush(FILE *)

The fflush() function only flushes the application level buffers in the stdio library to be flushed to the filesystem's buffers it does not flush the filesytem buffers to disk. That is ONLY accomplished by opening the file O_SYNC which causes all I/O to the file to be flushed from the buffer cache to disk immediately.

Art S. Kagel Received on Thu Dec 10 1998 - 10:38:34 CST