Author: jstephens
Date: 2007-05-18 15:46:23 +0200 (Fri, 18 May 2007)
New Revision: 6528
Log:
More reworked Cluster 5.0 Limitations sections.
Modified:
trunk/refman-5.0/mysql-cluster-limitations-working.xml
Modified: trunk/refman-5.0/mysql-cluster-limitations-working.xml
===================================================================
--- trunk/refman-5.0/mysql-cluster-limitations-working.xml 2007-05-18 13:45:31 UTC (rev 6527)
+++ trunk/refman-5.0/mysql-cluster-limitations-working.xml 2007-05-18 13:46:23 UTC (rev 6528)
Changed blocks: 1, Lines Added: 167, Lines Deleted: 3; 6245 bytes
@@ -759,13 +759,177 @@
<section id="mysql-cluster-limitations-error-handling">
<title></title>
</section>
-
<section id="mysql-cluster-limitations-database-objects">
- <title></title>
+
+ <title>Limits Associated with Database Objects</title>
+
+ <indexterm>
+ <primary>MySQL Cluster limitations</primary>
+ <secondary>database objects</secondary>
+ </indexterm>
+
+ <para>
+ Some database objects such as tables and indexes have different
+ limitations when using the <literal>NDBCLUSTER</literal> storage
+ engine:
+
+ <itemizedlist>
+
+ <listitem><formalpara>
+ <title>Identifiers</title>
+ <para>
+ Database names, table names and attribute names cannot be as
+ long in <literal>NDB</literal> tables as when using other
+ table handlers. Attribute names are truncated to 31
+ characters, and if not unique after truncation give rise to
+ errors. Database names and table names can total a maximum
+ of 122 characters. In other words, the maximum length for an
+ <literal>NDB</literal> table name is 122 characters, less
+ the number of characters in the name of the database of
+ which that table is a part.
+ </para>
+ </formalpara>
+ </listitem>
+
+ <listitem>
+ <formalpara>
+ <title>Number of tables</title>
+ <para>
+ The maximum number of <literal>NDB</literal> tables is
+ limited to 20320.
+ </para></formalpara>
+ </listitem>
+
+ <listitem><formalpara>
+ <title>Attributes per table</title>
+ <para>
+ The maximum number of attributes (that is, columns and
+ indexes) per table is limited to 128.
+ </para></formalpara>
+ </listitem>
+
+ <listitem><formalpara>
+ <title>Attributes per key</title>
+ <para>
+ The maximum number of attributes per key is 32.
+ </para></formalpara>
+ </listitem>
+
+ <listitem><formalpara>
+ <title>Row size</title>
+ <para>
+ The maximum permitted size of any one row is 8KB. Note that
+ each <literal>BLOB</literal> or <literal>TEXT</literal>
+ column contributes 256 + 8 = 264 bytes towards this total.
+ </para></formalpara>
+ </listitem>
+
+ </itemizedlist>
+ </para>
+
</section>
<section id="mysql-cluster-limitations-unsupported-missing">
- <title></title>
+
+ <title>Unsupported Or Missing Features</title>
+
+ <indexterm>
+ <primary>MySQL Cluster limitations</primary>
+ <secondary>unsupported features</secondary>
+ </indexterm>
+
+ <formalpara>
+
+ <title>Unsupported Features</title>
+
+ <para>
+ A number of features supported by other storage engines are not
+ supported for <literal>NDB</literal> tables. Trying to use any
+ of these features in MySQL Cluster does not cause errors in or
+ of itself; however, errors may occur in applications that
+ expects the features to be supported or enforced:
+
+ <itemizedlist>
+
+ <listitem><formalpara>
+ <title>Foreign key constraints</title>
+ <para>
+ The foreign key construct is ignored, just as it is in
+ <literal>MyISAM</literal> tables.
+ </para></formalpara>
+ </listitem>
+
+ <listitem><formalpara>
+ <title>Savepoints and rollbacks</title>
+ <para>
+ Savepoints and rollbacks to savepoints are ignored as in
+ <literal>MyISAM</literal>.
+ </para></formalpara>
+ </listitem>
+
+ <listitem>
+ <formalpara>
+ <title><literal>OPTIMIZE</literal> operations</title>
+ <para>
+ <literal>OPTIMIZE</literal> operations are not supported.
+ </para></formalpara>
+ </listitem>
+
+ <listitem><formalpara>
+ <title><literal>LOAD TABLE ... FROM MASTER</literal></title>
+ <para>
+ <literal>LOAD TABLE ... FROM MASTER</literal> is not
+ supported.
+ </para></formalpara>
+ </listitem>
+
+ </itemizedlist>
+ </para>
+
+ </formalpara>
+
+ <formalpara>
+
+ <title>Missing Features</title>
+
+ <para>
+ <itemizedlist>
+
+ <listitem><formalpara>
+ <title>Transaction isolation</title>
+ <para>
+ The only supported isolation level is <literal>READ
+ COMMITTED</literal>. (InnoDB supports <literal>READ
+ COMMITTED</literal>, <literal>READ UNCOMMITTED</literal>,
+ <literal>REPEATABLE READ</literal>, and
+ <literal>SERIALIZABLE</literal>.) See
+ <xref linkend="mysql-cluster-backup-troubleshooting"/>,
+ for information on how this can affect backup and restore
+ of Cluster databases.
+ </para></formalpara>
+ </listitem>
+
+ <listitem><formalpara>
+ <title>Durability</title>
+ <para>
+ No durable commits on disk. Commits are replicated, but
+ there is no guarantee that logs are flushed to disk on
+ commit.
+ </para></formalpara>
+ </listitem>
+
+ </itemizedlist>
+ </para>
+
+ </formalpara>
+
+ <note>
+ <para>
+ See <xref linkend="mysql-cluster-limitations-transactions"/>,
+ for more information relating to limitations on transaction
+ handling in <literal>NDB</literal>.
+ </para>
+ </note>
</section>
<section id="mysql-cluster-limitations-performance">
| Thread |
|---|
| • svn commit - mysqldoc@docsrva: r6528 - trunk/refman-5.0 | jon | 18 May |
