From: jon
Date: September 8 2008 9:04am
Subject: svn commit - mysqldoc@docsrva: r11716 - trunk/refman-5.1
List-Archive: http://lists.mysql.com/commits/53488
Message-Id: <200809080904.m8894lE3007686@docsrva.mysql.com>
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Author: jstephens
Date: 2008-09-08 11:04:47 +0200 (Mon, 08 Sep 2008)
New Revision: 11716
Log:
Fix description of EXTENT_SIZE (Jonas)
Fixes Docs Bug#39177
Modified:
trunk/refman-5.1/sql-syntax-data-definition.xml
Modified: trunk/refman-5.1/sql-syntax-data-definition.xml
===================================================================
--- trunk/refman-5.1/sql-syntax-data-definition.xml 2008-09-08 07:57:22 UTC (rev 11715)
+++ trunk/refman-5.1/sql-syntax-data-definition.xml 2008-09-08 09:04:47 UTC (rev 11716)
Changed blocks: 2, Lines Added: 8, Lines Deleted: 9; 2068 bytes
@@ -5394,7 +5394,9 @@
extents used by any files belonging to the tablespace. The default
value is 1M. The minimum size is 32K, and the theoretical maximum
is 2G, although the practical maximum size depends on a number of
- factors.
+ factors. In most cases, changing the extent size does not have any
+ measurable effect on performance, and the default value is
+ recommended for all but the most unusual situations.
@@ -5404,17 +5406,14 @@
(64K) extents may used per data file; however, the recommended
maximum is 32,768 (32K). The recommended maximum size for a single
data file is 32G — that is, 32K extents × 1 MB per
- extent. Smaller extents have the advantage that they tend to
- provide lower latency; however, larger extents tend to allow for
- greater throughput. You must also take into consideration that
- larger extents may mean longer node restart times. In addition,
- once an extent is allocated to a given table, it cannot be used to
- store data from another; an extent cannot store table from more
- than one table. This means, for example that a tablespace having a
+ extent. In addition, once an extent is allocated to a given
+ partition, it cannot be used to store data from a different
+ partition; an extent cannot store data from more than one
+ partition. This means, for example that a tablespace having a
single datafile whose INITIAL_SIZE is 256 MB
and whose EXTENT_SIZE is 128M has just two
extents, and so can be used to store data from at most two
- different disk data tables.
+ different disk data table partitions.