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Home -> Community -> Mailing Lists -> Oracle-L -> Re: fast_start_io_target -- which buffer?
No, I think they are referring to the Data buffer Cache buffers. My
understanding is that when data is changed, DBWn writes to a data block
buffer in the Buffer Cache, and LGWR writes the before and after data to
the Redo Log Buffer. Then for instance, at a checkpoint, the DBWn writes
out it's dirty buffers from the buffer cache to the datafiles and LGWR
writes to the logfiles.
-Scott
At 01:03 PM 4/7/03 -0800, you wrote:
>according to the Oracle documentation for FAST_START_IO_TARGET...
>
>----------------------------------------
>Set this parameter to n, where n is an integer limiting to n the number of
>"buffers" that Oracle processes during crash or instance recovery. Because
>the number of I/Os to be processed during recovery correlates closely to
>the duration of recovery, the FAST_START_IO_TARGET parameter gives you the
>most precise control over the duration of recovery.
>
>FAST_START_IO_TARGET advances the checkpoint, because DBWn uses the value
>of FAST_START_IO_TARGET to determine how much writing to do. Assuming that
>users are making many updates to the database, a low value for this
>parameter forces DBWn to write changed "buffers" to disk. As the changed
>"buffers" are written to disk, the checkpoint advances.
>
>The smaller the value of FAST_START_IO_TARGET, the better the recovery
>performance, because fewer blocks require recovery. If you use smaller
>values for this parameter, however, then you impose higher overhead during
>normal processing, because DBWn must write more buffers to disk more
>frequently.
>-----------------------------------------
>
>My question... which "buffers" are they referring to here? The log buffer?
>
>Thanks!!
>
>Nick
>
>
>
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Scott Stefick INET: sstefick_at_harpercollege.edu Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Mon Apr 07 2003 - 16:58:50 CDT
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