Oracle-L: RE: fast_start_io_target -- which buffer?

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Mon, 07 Apr 2003 13:53:58 -0800
Message-ID: <F001.0057C5D6.20030407135358@fatcity.com>

Nick - Data buffers. Specifically dirty data buffers (modified). The Oracle secret to high transaction throughput is that it never writes anything to disk until to optimum time. An Oracle trivia question (as in OCP trivia) is
"when does the Oracle data buffer contain no dirty buffers?".

Dennis Williams
DBA, 40%OCP, 100% DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Monday, April 07, 2003 4:04 PM
To: Multiple recipients of list ORACLE-L

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. BM_434315
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.
BM_434316
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

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Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM

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Received on Mon Apr 07 2003 - 16:53:58 CDT