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| From: | jon | Date: | May 18 2007 10:03am |
| Subject: | svn commit - mysqldoc@docsrva: r6518 - trunk/refman-5.1 | ||
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Author: jstephens Date: 2007-05-18 10:03:02 +0200 (Fri, 18 May 2007) New Revision: 6518 Log: Reformat. Modified: trunk/refman-5.1/mysql-cluster-limitations-working.xml Modified: trunk/refman-5.1/mysql-cluster-limitations-working.xml =================================================================== --- trunk/refman-5.1/mysql-cluster-limitations-working.xml 2007-05-17 21:42:47 UTC (rev 6517) +++ trunk/refman-5.1/mysql-cluster-limitations-working.xml 2007-05-18 08:03:02 UTC (rev 6518) Changed blocks: 15, Lines Added: 993, Lines Deleted: 891; 84107 bytes @@ -6,49 +6,48 @@ %all.entities; ]> <section id="mysql-cluster-limitations"> - + <title>Known Limitations of MySQL Cluster</title> - <indexterm> - <primary>MySQL Cluster limitations</primary> - </indexterm> + <indexterm> + <primary>MySQL Cluster limitations</primary> + </indexterm> - <indexterm> - <primary>limitations of MySQL Cluster</primary> + <indexterm> + <primary>limitations of MySQL Cluster</primary> <!-- <see>MySQL Cluster limitations</see> --> - </indexterm> + </indexterm> - <para> - In the sections that follow, we discuss known limitations in MySQL - ¤t-series; Cluster and &mccge-series; releases as compared - with the features available when using the - <literal>MyISAM</literal> and <literal>InnoDB</literal> storage - engines. Currently, there are no plans to address these in coming - releases of MySQL ¤t-series; or &mccge-series;; however, we - will attempt to supply fixes for these issues in subsequent - release series. If you check the <quote>Cluster</quote> category - in the MySQL bugs database at - <ulink url="http://bugs.mysql.com"/>, you can find known bugs - which (if marked <quote>¤t-series;</quote>) we intend to - correct in upcoming releases of MySQL ¤t-series;. Some of - these issues may be addressed in &mccge-series; and the fixes - included in a future mainline MySQL Cluster version. - </para> + <para> + In the sections that follow, we discuss known limitations in MySQL + ¤t-series; Cluster and &mccge-series; releases as compared + with the features available when using the <literal>MyISAM</literal> + and <literal>InnoDB</literal> storage engines. Currently, there are + no plans to address these in coming releases of MySQL + ¤t-series; or &mccge-series;; however, we will attempt to + supply fixes for these issues in subsequent release series. If you + check the <quote>Cluster</quote> category in the MySQL bugs database + at <ulink url="http://bugs.mysql.com"/>, you can find known bugs + which (if marked <quote>¤t-series;</quote>) we intend to + correct in upcoming releases of MySQL ¤t-series;. Some of + these issues may be addressed in &mccge-series; and the fixes + included in a future mainline MySQL Cluster version. + </para> - <para> - This information is intended to be complete with respect to the - conditions just set forth. You can report any discrepancies that - you encounter to the MySQL bugs database using the instructions - given in <xref linkend="bug-reports"/>. If we do not plan to fix - the problem in MySQL ¤t-series;, we will add it to the list. - </para> + <para> + This information is intended to be complete with respect to the + conditions just set forth. You can report any discrepancies that you + encounter to the MySQL bugs database using the instructions given in + <xref linkend="bug-reports"/>. If we do not plan to fix the problem + in MySQL ¤t-series;, we will add it to the list. + </para> - <para> - (<emphasis role="bold">Note</emphasis>: See the end of this - section for a list of issues in MySQL &previous-series; Cluster - that have been resolved in the current version.) - </para> - + <para> + (<emphasis role="bold">Note</emphasis>: See the end of this section + for a list of issues in MySQL &previous-series; Cluster that have + been resolved in the current version.) + </para> + <note> <para> Limitations and other issues specific to MySQL Cluster Replication @@ -56,152 +55,173 @@ <xref linkend="mysql-cluster-replication-issues"/>. </para> </note> - + <section id="mysql-cluster-limitations-syntax"> + <title>Non-Compliance In SQL Syntax</title> + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>syntax</secondary> </indexterm> - + <para> Some SQL statements relating to certain MySQL features produce errors when used with <literal>NDB</literal> tables, as described in the following list: - + <itemizedlist> - + <listitem> <formalpara> - <title>Temporary tables</title> - <para> - Temporary tables are not supported. Trying either to create - a temporary table that uses the <literal>NDB</literal> - storage engine or to alter an existing temporary table to - use <literal>NDB</literal> fails with the error - <errortext>Table storage engine 'ndbcluster' does not - support the create option 'TEMPORARY'</errortext>. - </para> + + <title>Temporary tables</title> + + <para> + Temporary tables are not supported. Trying either to + create a temporary table that uses the + <literal>NDB</literal> storage engine or to alter an + existing temporary table to use <literal>NDB</literal> + fails with the error <errortext>Table storage engine + 'ndbcluster' does not support the create option + 'TEMPORARY'</errortext>. + </para> + </formalpara> </listitem> - + <listitem> <formalpara> - <title>Indexes and keys in <literal>NDB</literal> tables</title> - + + <title>Indexes and keys in <literal>NDB</literal> tables</title> + <para> - Keys and indexes on MySQL Cluster tables are subject to the - following limitations: + Keys and indexes on MySQL Cluster tables are subject to + the following limitations: + <itemizedlist> + <listitem> - <para> - You cannot create indexes on <literal>NDB</literal> table - columns that use any of the <literal>TEXT</literal> or - <literal>BLOB</literal> data types. + You cannot create indexes on <literal>NDB</literal> + table columns that use any of the + <literal>TEXT</literal> or <literal>BLOB</literal> + data types. </para> </listitem> + <listitem> - <para> The <literal>NDB</literal> storage engine does not support <literal>FULLTEXT</literal> indexes, which - are possible for <literal>MyISAM</literal> tables only. + are possible for <literal>MyISAM</literal> tables + only. </para> + <para> However, you can create indexes on <literal>VARCHAR</literal> columns of <literal>NDB</literal> tables. </para> </listitem> - + <listitem> <para> - A <literal>BIT</literal> column cannot be a primary key, - unique key, or index, nor can it be part of a composite - primary key, unique key, or index. + A <literal>BIT</literal> column cannot be a primary + key, unique key, or index, nor can it be part of a + composite primary key, unique key, or index. </para> </listitem> - + <listitem> <formalpara> + <title>Duplicate keys</title> - <para> - A duplicate key error returns the error message - <errortext>ERROR 23000: Can't write; duplicate key in - table + + <para> + A duplicate key error returns the error message + <errortext>ERROR 23000: Can't write; duplicate key + in table '<replaceable>tbl_name</replaceable>'</errortext>. - </para> + </para> + </formalpara> </listitem> - + <listitem> <formalpara> - <title><literal>AUTO_INCREMENT</literal> columns</title> - <para> - Like other MySQL storage engines, the - <literal>NDB</literal> storage engine can handle a - maximum of one <literal>AUTO_INCREMENT</literal> - column per table. However, in the case of a Cluster - table with no explicit primary key, an - <literal>AUTO_INCREMENT</literal> column is - automatically defined and used as a - <quote>hidden</quote> primary key. For this reason, - you cannot define a table that has an explicit - <literal>AUTO_INCREMENT</literal> column unless that - column is also declared using the <literal>PRIMARY - KEY</literal> option. Attempting to create a table with an - <literal>AUTO_INCREMENT</literal> column that is not - the table's primary key, and using the - <literal>NDB</literal> storage engine, fails with an - error. - </para> + + <title><literal>AUTO_INCREMENT</literal> columns</title> + + <para> + Like other MySQL storage engines, the + <literal>NDB</literal> storage engine can handle a + maximum of one <literal>AUTO_INCREMENT</literal> + column per table. However, in the case of a + Cluster table with no explicit primary key, an + <literal>AUTO_INCREMENT</literal> column is + automatically defined and used as a + <quote>hidden</quote> primary key. For this + reason, you cannot define a table that has an + explicit <literal>AUTO_INCREMENT</literal> column + unless that column is also declared using the + <literal>PRIMARY KEY</literal> option. Attempting + to create a table with an + <literal>AUTO_INCREMENT</literal> column that is + not the table's primary key, and using the + <literal>NDB</literal> storage engine, fails with + an error. + </para> + </formalpara> </listitem> - + </itemizedlist> </para> - - + </formalpara> - </listitem> - + <listitem> <formalpara> - <title>MySQL Cluster and geometry data types</title> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>geometry data types</secondary> - </indexterm> - - <para> - Geometry datatypes (<literal>WKT</literal> and - <literal>WKB</literal>) are supported in - <literal>NDB</literal> tables in MySQL ¤t-series;. - However, spatial indexes are not supported. - </para> + + <title>MySQL Cluster and geometry data types</title> + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>geometry data types</secondary> + </indexterm> + + <para> + Geometry datatypes (<literal>WKT</literal> and + <literal>WKB</literal>) are supported in + <literal>NDB</literal> tables in MySQL ¤t-series;. + However, spatial indexes are not supported. + </para> + </formalpara> </listitem> - + <listitem> <indexterm> <primary>MySQL Cluster</primary> <secondary>partitioning support</secondary> </indexterm> - + <indexterm> <primary>partitioning</primary> <secondary>support in MySQL Cluster</secondary> </indexterm> - + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>partitioning</secondary> </indexterm> + <formalpara> + <title>Creating <literal>NDB</literal> tables with user-defined partitioning</title> - + <para> Support for user-defined partitioning for MySQL Cluster in MySQL ¤t-series; is restricted to @@ -211,8 +231,9 @@ <literal>ENGINE=NDBCLUSTER</literal> in a <literal>CREATE TABLE</literal> statement results in an error. </para> + </formalpara> - + <para> As of MySQL 5.1.6, all Cluster tables are by default partitioned by <literal>KEY</literal> using the table's @@ -223,36 +244,41 @@ additional discussion of these and related issues, see <xref linkend="partitioning-key"/>. </para> + <formalpara> + <title><literal>DROP PARTITION</literal> not supported</title> - <para> - It is not possible to drop partitions from - <literal>NDB</literal> tables using <literal>ALTER TABLE + + <para> + It is not possible to drop partitions from + <literal>NDB</literal> tables using <literal>ALTER TABLE ... DROP PARTITION</literal>. The other partitioning - extensions to <literal>ALTER TABLE</literal> — - <literal>ADD PARTITION</literal>, <literal>REORGANIZE + extensions to <literal>ALTER TABLE</literal> — + <literal>ADD PARTITION</literal>, <literal>REORGANIZE PARTITION</literal>, and <literal>COALESCE - PARTITION</literal> — are supported for Cluster - tables, but use copying and so are not optimised. See - <xref linkend="partitioning-management-range-list"/> and - <xref linkend="alter-table"/>. - </para></formalpara> + PARTITION</literal> — are supported for Cluster + tables, but use copying and so are not optimised. See + <xref linkend="partitioning-management-range-list"/> and + <xref linkend="alter-table"/>. + </para> + + </formalpara> </listitem> - + <listitem> - <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>replication</secondary> </indexterm> + <para> - When using row-based replication with MySQL Cluster, - binary logging cannot be disabled. That is, the + When using row-based replication with MySQL Cluster, binary + logging cannot be disabled. That is, the <literal>NDB</literal> storage engine ignores the value of <literal>SQL_LOG_BIN</literal>. (Bug #16680) </para> </listitem> - + <listitem> <para> The <literal>auto_increment_increment</literal> and @@ -260,83 +286,95 @@ variables are not supported for Cluster replication. </para> </listitem> - + </itemizedlist> </para> + </section> - + <section id="mysql-cluster-limitations-limits"> + <title>Limits and Differences from Standard MySQL Limits</title> + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>and differences from standard MySQL limits</secondary> </indexterm> - + <para> In this section, we list limits found in MySQL Cluster that either - differ from limits found in, or that are not found in, standard MySQL. + differ from limits found in, or that are not found in, standard + MySQL. + <itemizedlist> - <listitem> - <indexterm> - <primary>memory use</primary> - <secondary>in MySQL Cluster</secondary> - </indexterm> + <listitem> + <indexterm> + <primary>memory use</primary> + <secondary>in MySQL Cluster</secondary> + </indexterm> - <indexterm> - <primary>MySQL Cluster</primary> - <secondary>memory usage and recovery</secondary> - </indexterm> + <indexterm> + <primary>MySQL Cluster</primary> + <secondary>memory usage and recovery</secondary> + </indexterm> - <indexterm> - <primary><literal>DELETE</literal></primary> - <secondary>and MySQL Cluster</secondary> - </indexterm> + <indexterm> + <primary><literal>DELETE</literal></primary> + <secondary>and MySQL Cluster</secondary> + </indexterm> - <indexterm> - <primary><literal>DROP TABLE</literal></primary> - <secondary>and MySQL Cluster</secondary> - </indexterm> + <indexterm> + <primary><literal>DROP TABLE</literal></primary> + <secondary>and MySQL Cluster</secondary> + </indexterm> - <indexterm> - <primary><literal>TRUNCATE</literal></primary> - <secondary>and MySQL Cluster</secondary> - </indexterm> + <indexterm> + <primary><literal>TRUNCATE</literal></primary> + <secondary>and MySQL Cluster</secondary> + </indexterm> - <formalpara> - <title>Memory usage and recovery</title> - <para> + <formalpara> + + <title>Memory usage and recovery</title> + + <para> Memory comsumed when data is inserted into an <literal>NDB</literal> table is not automatically recovered when deleted, as it is with other storage engines. Instead, the following rules hold true: + <itemizedlist> - + <listitem> <para> A <literal>DELETE</literal> statement on an - <literal>NDB</literal> table makes the memory formerly - used by the deleted rows available for re-use by - inserts on the same table only. This memory cannot be - used by other <literal>NDB</literal> tables. + <literal>NDB</literal> table makes the memory + formerly used by the deleted rows available for + re-use by inserts on the same table only. This + memory cannot be used by other + <literal>NDB</literal> tables. </para> </listitem> - + <listitem> <para> A <literal>DROP TABLE</literal> or <literal>TRUNCATE</literal> operation on an - <literal>NDB</literal> table frees the memory that was - used by this table for re-use by any - <literal>NDB</literal> table, either by the - same table or by another <literal>NDB</literal> table. + <literal>NDB</literal> table frees the memory that + was used by this table for re-use by any + <literal>NDB</literal> table, either by the same + table or by another <literal>NDB</literal> table. </para> + <note> - <para> - Recall that <literal>TRUNCATE</literal> drops and - re-creates the table. See <xref linkend="truncate"/>. - </para> + <para> + Recall that <literal>TRUNCATE</literal> drops and + re-creates the table. See + <xref linkend="truncate"/>. + </para> </note> + <para> Memory freed by <literal>DELETE</literal> operations but still allocated to a specific table can also be @@ -345,177 +383,196 @@ <xref linkend="mysql-cluster-rolling-restart"/>. </para> </listitem> + <listitem> <formalpara> + <title>Limits imposed by the cluster's configuration</title> - + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>imposed by configuration</secondary> </indexterm> + <para> - A number of hard limits exist which are configurable, but - available main memory in the cluster sets limits. See the - complete list of configuration parameters in + A number of hard limits exist which are + configurable, but available main memory in the + cluster sets limits. See the complete list of + configuration parameters in <xref linkend="mysql-cluster-config-file"/>. Most - configuration parameters can be upgraded online. These - hard limits include:<itemizedlist> - + configuration parameters can be upgraded online. + These hard limits include: + + <itemizedlist> + <listitem> <para> Database memory size and index memory size (<literal>DataMemory</literal> and - <literal>IndexMemory</literal>, respectively). + <literal>IndexMemory</literal>, + respectively). </para> - + <para> - <literal>DataMemory</literal> is allocated as 32KB - pages. As each <literal>DataMemory</literal> page is - used, it is assigned to a specific table; once - allocated, this memory cannot be freed except by - dropping the table. + <literal>DataMemory</literal> is allocated + as 32KB pages. As each + <literal>DataMemory</literal> page is used, + it is assigned to a specific table; once + allocated, this memory cannot be freed + except by dropping the table. </para> - + <para> - See <xref linkend="mysql-cluster-ndbd-definition"/>, + See + <xref linkend="mysql-cluster-ndbd-definition"/>, for further information about <literal>DataMemory</literal> and <literal>IndexMemory</literal>. </para> </listitem> - + <listitem> <para> - The maximum number of operations that can be performed - per transaction is set using the configuration - parameters - <literal>MaxNoOfConcurrentOperations</literal> and - <literal>MaxNoOfLocalOperations</literal>. Note that - bulk loading, <literal>TRUNCATE TABLE</literal>, and - <literal>ALTER TABLE</literal> are handled as special - cases by running multiple transactions, and so are not - subject to this limitation. + The maximum number of operations that can be + performed per transaction is set using the + configuration parameters + <literal>MaxNoOfConcurrentOperations</literal> + and + <literal>MaxNoOfLocalOperations</literal>. + Note that bulk loading, <literal>TRUNCATE + TABLE</literal>, and <literal>ALTER + TABLE</literal> are handled as special cases + by running multiple transactions, and so are + not subject to this limitation. </para> </listitem> - + <listitem> <para> - Different limits related to tables and indexes. For - example, the maximum number of ordered indexes per - table is determined by + Different limits related to tables and + indexes. For example, the maximum number of + ordered indexes per table is determined by <literal>MaxNoOfOrderedIndexes</literal>. </para> </listitem> - + </itemizedlist> </para> + </formalpara> - - - - - </listitem> - - + <listitem> <formalpara> + <title>Node and data object maximums</title> + <para> The following limits apply to numbers of cluster nodes and metadata objects: + <itemizedlist> - <listitem> - <para> - The maximum number of data nodes is 48. - </para> - </listitem> - - <listitem> - <para> - The total maximum number of nodes in a MySQL - Cluster is 63. This number includes all SQL nodes - (MySQL Servers), API nodes (applications accessing - the cluster other than MySQL servers), data nodes, - and management servers. - </para> - - </listitem> - - <listitem> - <para> - The maximum number of metadata objects in MySQL - ¤t-series; Cluster and &mccge-series; is - 20320. This limit is hard-coded. - </para> - </listitem> + + <listitem> + <para> + The maximum number of data nodes is 48. + </para> + </listitem> + + <listitem> + <para> + The total maximum number of nodes in a MySQL + Cluster is 63. This number includes all SQL + nodes (MySQL Servers), API nodes + (applications accessing the cluster other + than MySQL servers), data nodes, and + management servers. + </para> + </listitem> + + <listitem> + <para> + The maximum number of metadata objects in + MySQL ¤t-series; Cluster and + &mccge-series; is 20320. This limit is + hard-coded. + </para> + </listitem> + </itemizedlist> + <note> <para role="mccge-warning"> - &mccge-series; users should see + &mccge-series; users should see <xref linkend="mysql-cluster-limitations-resolved"/>, for more information. </para> </note> </para> - </formalpara></listitem> - - + + </formalpara> + </listitem> + </itemizedlist> </para> - </formalpara> - - </listitem> + </formalpara> + </listitem> + </itemizedlist> - </para> + </section> - + <section id="mysql-cluster-limitations-transactions"> - + <title>Limits Relating to Transaction Handling</title> + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>transactions</secondary> </indexterm> - + <para> A numbe of limitations exist in MySQL Cluster with regard to the handling of transactions. These include the following: - + <itemizedlist> - + <listitem> <para> The <literal>NDBCLUSTER</literal> storage engine supports only the <literal>READ COMMITTED</literal> transaction isolation level. </para> + <important> - <para> - If a - <literal>SELECT</literal> from a Cluster table - includes a <literal>BLOB</literal> or - <literal>TEXT</literal> column, the <literal>READ + <para> + If a <literal>SELECT</literal> from a Cluster table + includes a <literal>BLOB</literal> or + <literal>TEXT</literal> column, the <literal>READ COMMITTED</literal> transaction isolation level is - converted to a read with read lock. This is done to - guarantee consistency, due to the fact that parts of - the values stored in columns of these types are - actually read from a separate table. - </para> + converted to a read with read lock. This is done to + guarantee consistency, due to the fact that parts of the + values stored in columns of these types are actually read + from a separate table. + </para> </important> </listitem> - + <listitem> <formalpara> + <title>Rollbacks</title> - <para> - There is no partial rollback of transactions. A duplicate - key or similar error rolls back the entire transaction. - </para></formalpara> + + <para> + There is no partial rollback of transactions. A duplicate + key or similar error rolls back the entire transaction. + </para> + + </formalpara> </listitem> - + <listitem> <para> As noted elsewhere in this chapter, MySQL Cluster does not @@ -524,25 +581,25 @@ to attempt a single large transaction containing a great many operations. </para> - + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>memory usage and transaction handling</secondary> </indexterm> - + <indexterm> <primary>MySQL Cluster</primary> <secondary>transaction handling</secondary> </indexterm> - + <para> Among other considerations, large transactions require very large amounts of memory. Because of this, the transactional behaviour of a number of MySQL statements is effected as described in the following list: - + <itemizedlist> - + <listitem> <para> <literal>TRUNCATE</literal> is not transactional when @@ -551,7 +608,7 @@ then it must be re-run until it is successful. </para> </listitem> - + <listitem> <para> <literal>DELETE FROM</literal> (even with no @@ -562,110 +619,120 @@ <literal>DELETE FROM ... LIMIT ...</literal> statements to <quote>chunk</quote> the delete operation. If your objective is to empty the table, - then you may wish to use - <literal>TRUNCATE</literal> instead. + then you may wish to use <literal>TRUNCATE</literal> + instead. </para> </listitem> - + <listitem> <formalpara> + <title><literal>LOAD DATA</literal> statements</title> - <para> - <literal>LOAD DATA INFILE</literal> is not - transactional when used on <literal>NDB</literal> - tables. - <important> - <para> - When executing a <literal>LOAD DATA - INFILE</literal> statement, the - <literal>NDB</literal> engine can and does commit - at will. - </para> - </important> - <literal>LOAD DATA FROM MASTER</literal> is not - supported in MySQL Cluster. - </para> + + <para> + <literal>LOAD DATA INFILE</literal> is not + transactional when used on <literal>NDB</literal> + tables. + + <important> + <para> + When executing a <literal>LOAD DATA + INFILE</literal> statement, the + <literal>NDB</literal> engine can and does + commit at will. + </para> + </important> + + <literal>LOAD DATA FROM MASTER</literal> is not + supported in MySQL Cluster. + </para> + </formalpara> </listitem> - + <listitem> <formalpara> + <title><literal>ALTER TABLE</literal> and transactions</title> - <para> - When copying an <literal>NDB</literal> table as part - of an <literal>ALTER TABLE</literal>, the creation of - the copy is non-transactional. (In any case, this - operation is rolled back when the copy is deleted.) - </para> + + <para> + When copying an <literal>NDB</literal> table as part + of an <literal>ALTER TABLE</literal>, the creation + of the copy is non-transactional. (In any case, this + operation is rolled back when the copy is deleted.) + </para> + </formalpara> </listitem> - + </itemizedlist> </para> - - - </listitem> + </listitem> + </itemizedlist> </para> + </section> - + <section id="mysql-cluster-limitations-error-handling"> + <title>Error Handling</title> - + <para> Starting, stopping, or restarting a node may give rise to temporary errors causing some transactions to fail. These include the following cases: + <itemizedlist> - + <listitem> <para> - When first starting a node, it is possible that - you may see Error 1204 <errortext>Temporary - failure, distribution changed</errortext> and - similar temporary errors. + When first starting a node, it is possible that you may see + Error 1204 <errortext>Temporary failure, distribution + changed</errortext> and similar temporary errors. </para> </listitem> - + <listitem> <para> - The stopping or failure of any data node can - result in a number of different node failure - errors. (However, there should be no aborted - transactions when performing a planned shutdown of - the cluster.) + The stopping or failure of any data node can result in a + number of different node failure errors. (However, there + should be no aborted transactions when performing a planned + shutdown of the cluster.) </para> </listitem> - + </itemizedlist> </para> - + <para> + In either of these cases, any errors that are generated must be + handled within the application. This should be done by retrying + the transaction. + </para> - <para> - In either of these cases, any errors that are - generated must be handled within the application. This - should be done by retrying the transaction. - </para> - + <para> + See also <xref linkend="mysql-cluster-limitations-limits"/>. + </para> - <para> - See also <xref linkend="mysql-cluster-limitations-limits"/>. - </para> - </section> + <section id="mysql-cluster-limitations-database-objects"> + <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> <para> Database names, table names and attribute names cannot be as @@ -673,112 +740,116 @@ 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. + of 122 characters. </para> - + <para> 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> - </listitem> + </para> + </listitem> + <listitem> + <para> + The maximum number of <literal>NDB</literal> tables is + limited to 20320. + </para> + </listitem> + + <listitem> + <para> + The maximum number of attributes (that is, columns and + indexes) per table is limited to 128. + </para> + </listitem> + + <listitem> + <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> + </listitem> + + <listitem> + <para> + The maximum number of attributes per key is 32. + </para> + </listitem> + + </itemizedlist> + </para> + + </section> + + <section id="mysql-cluster-limitations-unsupported-missing"> + + <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> <para> - The maximum number of <literal>NDB</literal> tables is - limited to 20320. + The foreign key construct is ignored, just as it is in + <literal>MyISAM</literal> tables. </para> </listitem> <listitem> <para> - The maximum number of attributes (that is, columns and - indexes) per table is limited to 128. + Savepoints and rollbacks to savepoints are ignored as in + <literal>MyISAM</literal>. </para> </listitem> <listitem> <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. + <literal>OPTIMIZE</literal> operations are not supported. </para> </listitem> <listitem> <para> - The maximum number of attributes per key is 32. + <literal>LOAD TABLE ... FROM MASTER</literal> is not + supported. </para> </listitem> - </itemizedlist> - - </para> - </section> - <section id="mysql-cluster-limitations-unsupported-missing"> - <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> - <para> - The foreign key construct is ignored, just as it is in - <literal>MyISAM</literal> tables. - </para> - </listitem> - - <listitem> - <para> - Savepoints and rollbacks to savepoints are ignored as in - <literal>MyISAM</literal>. - </para> - </listitem> - - <listitem> - <para> - <literal>OPTIMIZE</literal> operations are not supported. - </para> - </listitem> - - <listitem> - <para> - <literal>LOAD TABLE ... FROM MASTER</literal> is not - supported. - </para> - </listitem> - - </itemizedlist> - - </para> - </formalpara> - + + </itemizedlist> + </para> + + </formalpara> + <formalpara> + <title>Missing Features</title> + <para> - - <itemizedlist> - + <listitem> <para> The only supported isolation level is <literal>READ - COMMITTED</literal>. (InnoDB supports <literal>READ - COMMITTED</literal>, <literal>READ UNCOMMITTED</literal>, + 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"/>, @@ -786,7 +857,7 @@ of Cluster databases. </para> </listitem> - + <listitem> <para> No durable commits on disk. Commits are replicated, but @@ -794,294 +865,307 @@ commit. </para> </listitem> - + </itemizedlist> </para> + </formalpara> - - + </section> - + <section id="mysql-cluster-limitations-performance"> + <title>Limitations Relating to Performance</title> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>performance</secondary> - </indexterm> - - - + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>performance</secondary> + </indexterm> + <para> The following performance issues are specific to or especially pronounced in MySQL Cluster: - - <itemizedlist> - <listitem> - <para> - There are query performance issues due to sequential - access to the <literal>NDB</literal> storage engine; it is - also relatively more expensive to do many range scans than - it is with either <literal>MyISAM</literal> or - <literal>InnoDB</literal>. - </para> - </listitem> + <itemizedlist> - <listitem> - <para> - The <literal>Records in range</literal> statistic is - available but is not completely tested or officially - supported. This may result in non-optimal query plans in - some cases. If necessary, you can employ <literal>USE - INDEX</literal> or <literal>FORCE INDEX</literal> to alter - the execution plan. See <xref linkend="index-hints"/>, for - more information on how to do this. - </para> - </listitem> + <listitem> + <para> + There are query performance issues due to sequential access + to the <literal>NDB</literal> storage engine; it is also + relatively more expensive to do many range scans than it is + with either <literal>MyISAM</literal> or + <literal>InnoDB</literal>. + </para> + </listitem> - <listitem> - <para> - Unique hash indexes created with <literal>USING - HASH</literal> cannot be used for accessing a table if - <literal>NULL</literal> is given as part of the key. - </para> - </listitem> + <listitem> + <para> + The <literal>Records in range</literal> statistic is + available but is not completely tested or officially + supported. This may result in non-optimal query plans in + some cases. If necessary, you can employ <literal>USE + INDEX</literal> or <literal>FORCE INDEX</literal> to alter + the execution plan. See <xref linkend="index-hints"/>, for + more information on how to do this. + </para> + </listitem> - <listitem> - <para> - <literal>SQL_LOG_BIN</literal> has no effect on data - operations; however, it is supported for schema - operations. - </para> + <listitem> + <para> + Unique hash indexes created with <literal>USING + HASH</literal> cannot be used for accessing a table if + <literal>NULL</literal> is given as part of the key. + </para> + </listitem> - <para> - MySQL Cluster cannot produce a binlog for tables having - <literal>BLOB</literal> columns but no primary key. - </para> + <listitem> + <para> + <literal>SQL_LOG_BIN</literal> has no effect on data + operations; however, it is supported for schema operations. + </para> - <para> - Only the following schema operations are logged in a - cluster binlog which is <emphasis>not</emphasis> on the - <command>mysqld</command> executing the statement: - </para> + <para> + MySQL Cluster cannot produce a binlog for tables having + <literal>BLOB</literal> columns but no primary key. + </para> - <itemizedlist> + <para> + Only the following schema operations are logged in a cluster + binlog which is <emphasis>not</emphasis> on the + <command>mysqld</command> executing the statement: + </para> - <listitem> - <para> - <literal>CREATE TABLE</literal> - </para> - </listitem> + <itemizedlist> - <listitem> - <para> - <literal>ALTER TABLE</literal> - </para> - </listitem> + <listitem> + <para> + <literal>CREATE TABLE</literal> + </para> + </listitem> - <listitem> - <para> - <literal>DROP TABLE</literal> - </para> - </listitem> + <listitem> + <para> + <literal>ALTER TABLE</literal> + </para> + </listitem> - <listitem> - <para> - <literal>CREATE DATABASE</literal> / <literal>CREATE - SCHEMA</literal> - </para> - </listitem> + <listitem> + <para> + <literal>DROP TABLE</literal> + </para> + </listitem> - <listitem> - <para> - <literal>DROP DATABASE</literal> / <literal>DROP - SCHEMA</literal> - </para> - </listitem> + <listitem> + <para> + <literal>CREATE DATABASE</literal> / <literal>CREATE + SCHEMA</literal> + </para> + </listitem> - <listitem> - <para> - <literal>CREATE TABLESPACE</literal> - </para> - </listitem> + <listitem> + <para> + <literal>DROP DATABASE</literal> / <literal>DROP + SCHEMA</literal> + </para> + </listitem> - <listitem> - <para> - <literal>ALTER TABLESPACE</literal> - </para> - </listitem> + <listitem> + <para> + <literal>CREATE TABLESPACE</literal> + </para> + </listitem> - <listitem> - <para> - <literal>DROP TABLESPACE</literal> - </para> - </listitem> + <listitem> + <para> + <literal>ALTER TABLESPACE</literal> + </para> + </listitem> - <listitem> - <para> - <literal>CREATE LOGFILE GROUP</literal> - </para> - </listitem> + <listitem> + <para> + <literal>DROP TABLESPACE</literal> + </para> + </listitem> - <listitem> - <para> - <literal>ALTER LOGFILE GROUP</literal> - </para> - </listitem> + <listitem> + <para> + <literal>CREATE LOGFILE GROUP</literal> + </para> + </listitem> - <listitem> - <para> - <literal>DROP LOGFILE GROUP</literal> - </para> - </listitem> + <listitem> + <para> + <literal>ALTER LOGFILE GROUP</literal> + </para> + </listitem> - </itemizedlist> - </listitem> + <listitem> + <para> + <literal>DROP LOGFILE GROUP</literal> + </para> + </listitem> - </itemizedlist> - - + </itemizedlist> + </listitem> + + </itemizedlist> </para> - + </section> <section id="mysql-cluster-limitations-exclusive-to-cluster"> - - <title>Issues Exclusive to MySQL Cluster</title> - - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>implementation</secondary> - </indexterm> + <title>Issues Exclusive to MySQL Cluster</title> + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>implementation</secondary> + </indexterm> + + <para> + The following are limitations specific to the + <literal>NDBCLUSTER</literal> storage engine, and do not occur + with <literal>MyISAM</literal> or <literal>InnoDB</literal>: + + <itemizedlist> + + <listitem> + <formalpara> + + <title>Machine architecture</title> + + <para> + All machines used in the cluster must have the same + architecture. That is, all machines hosting nodes must be + either big-endian or little-endian, and you cannot use a + mixture of both. For example, you cannot have a management + node running on a PowerPC which directs a data node that + is running on an x86 machine. This restriction does not + apply to machines simply running <command>mysql</command> + or other clients that may be accessing the cluster's SQL + nodes. + </para> + + </formalpara> + </listitem> + + <listitem> + <formalpara> + + <title>Adding and dropping of data nodes</title> + + <para> + Online adding or dropping of data nodes is not currently + possible. In such cases, the entire cluster must be + restarted. + </para> + + </formalpara> + </listitem> + + <listitem> + <formalpara> + + <title>Multiple data node processes</title> + + <para> + While it is possible to run multiple cluster processes + concurrently on a single host, it is not always advisable + to do so for reasons of performance and high availability, + as well as other considerations. In particular, in MySQL + ¤t-series; or &mccge-series;, we do not support for + production use any MySQL Cluster deployment in which more + than one <command>ndbd</command> process is run on a + single physical machine. + </para> + + </formalpara> + + <para> + We may support multiple data nodes per host in a future + MySQL release, following additional testing. However, in + MySQL ¤t-series; and &mccge-series;, such + configurations can be considered experimental only. + </para> + </listitem> + + </itemizedlist> + </para> + + </section> + + <section id="mysql-cluster-limitations-disk-data"> + + <title>Limitation Relating to Disk Data Storage</title> + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>Disk Data storage</secondary> + </indexterm> + + <itemizedlist> + + <listitem> <para> - The following are limitations specific to the - <literal>NDBCLUSTER</literal> storage engine, and do not occur - with <literal>MyISAM</literal> or <literal>InnoDB</literal>:<itemizedlist> - + Disk data objects are subject to the following maximums: + + <itemizedlist> + <listitem> - <formalpara> - <title>Machine architecture</title> <para> - All machines used in the cluster must have the same - architecture. That is, all machines hosting nodes must be - either big-endian or little-endian, and you cannot use a - mixture of both. For example, you cannot have a management - node running on a PowerPC which directs a data node that - is running on an x86 machine. This restriction does not - apply to machines simply running <command>mysql</command> - or other clients that may be accessing the cluster's SQL - nodes. + Maxmimum number of tablespaces: 2^32 (4294967296) </para> - </formalpara> </listitem> - + <listitem> - <formalpara> - <title>Adding and dropping of data nodes</title> <para> - Online adding or dropping of data nodes is not currently - possible. In such cases, the entire cluster must be restarted. + Maximum number of data files per tablespace: 2^16 + (65535) </para> - </formalpara> </listitem> - + <listitem> - <formalpara> - <title>Multiple data node processes</title> - <para> - While it is possible to run multiple cluster processes - concurrently on a single host, it is not always - advisable to do so for reasons of performance and high - availability, as well as other considerations. In - particular, in MySQL ¤t-series; or - &mccge-series;, we do not support for production use - any MySQL Cluster deployment in which more than one - <command>ndbd</command> process is run on a single - physical machine. - </para> - </formalpara> - <para> - We may support multiple data nodes per host in a future - MySQL release, following additional testing. However, in - MySQL ¤t-series; and &mccge-series;, such - configurations can be considered experimental only. + Maxmimum data file size: 2^47 (128GB) </para> </listitem> + </itemizedlist> </para> + </listitem> + + <listitem> + <para> + Use of Disk Data tables is not supported when running the + cluster in diskless mode. Beginning with MySQL 5.1.12, it is + disallowed altogether. (Bug #20008) + </para> + </listitem> + + </itemizedlist> + </section> - - <section id="mysql-cluster-limitations-disk-data"> - - <title>Limitation Relating to Disk Data Storage</title> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>Disk Data storage</secondary> - </indexterm><itemizedlist> - <listitem> - <para> - Disk data objects are subject to the following - maximums: - - <itemizedlist> - - <listitem> - <para> - Maxmimum number of tablespaces: 2^32 - (4294967296) - </para> - </listitem> - - <listitem> - <para> - Maximum number of data files per tablespace: - 2^16 (65535) - </para> - </listitem> - - <listitem> - <para> - Maxmimum data file size: 2^47 (128GB) - </para> - </listitem> - - </itemizedlist> - </para> - </listitem> - - <listitem> - <para> - Use of Disk Data tables is not supported when - running the cluster in diskless mode. Beginning with - MySQL 5.1.12, it is disallowed altogether. (Bug - #20008) - </para> - </listitem> - - - </itemizedlist> - - </section> - + <section id="mysql-cluster-limitations-multiple-nodes"> - <title>Limitations Relating to Multiple Cluster Nodes</title> + + <title>Limitations Relating to Multiple Cluster Nodes</title> + <formalpara> + <title>Multiple SQL nodes</title> + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>multiple MySQL servers</secondary> </indexterm> - + <para> - The following are issues relating to the use of multiple MySQL servers - as MySQL Cluster SQL nodes, and are specific to the + The following are issues relating to the use of multiple MySQL + servers as MySQL Cluster SQL nodes, and are specific to the <literal>NDBCLUSTER</literal> storage engine: - + <itemizedlist> - + <listitem> <para> <literal>ALTER TABLE</literal> is not fully locking when @@ -1089,89 +1173,96 @@ lock). </para> </listitem> - + <listitem> <para> DDL operations (such as <literal>CREATE TABLE</literal> or - <literal>ALTER TABLE</literal>) are not safe from data node - failures. If a data node fails while trying to peform one of - these, the data dictionary is locked and no further DDL - statements can be executed without restarting the cluster. + <literal>ALTER TABLE</literal>) are not safe from data + node failures. If a data node fails while trying to peform + one of these, the data dictionary is locked and no further + DDL statements can be executed without restarting the + cluster. </para> </listitem> - + </itemizedlist> </para> + </formalpara> - + <formalpara> + <title>Multiple management nodes</title> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>multiple management servers</secondary> - </indexterm> - - <para> - When using multiple management servers:<itemizedlist> - - <listitem> - <para> - You must give nodes explicit IDs in connectstrings - because automatic allocation of node IDs does not work - across multiple management servers. - </para> - </listitem> - - <listitem> - <para> - You must take extreme care to have the same - configurations for all management servers. No special - checks for this are performed by the cluster. - </para> - </listitem> - - </itemizedlist> - </para> - - </formalpara> - <itemizedlist> - - - <listitem> - <formalpara> - <title>Multiple network addresses</title> - - <para> - Multiple network addresses per data node are not - supported. Use of these is liable to cause problems: - In the event of a data node failure, an SQL node waits - for confirmation that the data node went down but - never receives it because another route to that data - node remains open. This can effectively make the - cluster inoperable. - </para> - </formalpara> - - <para> - It is possible to use multiple network hardware - <emphasis>interfaces</emphasis> (such as Ethernet cards) - for a single data node, but these must be bound to the - same address. This also means that it not possible to - use more than one <literal>[TCP]</literal> section per - connection in the <literal>config.ini</literal> file. - See <xref linkend="mysql-cluster-tcp-definition"/>, for - more information. - </para> - </listitem> - - </itemizedlist> - - + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>multiple management servers</secondary> + </indexterm> + + <para> + When using multiple management servers: + + <itemizedlist> + + <listitem> + <para> + You must give nodes explicit IDs in connectstrings because + automatic allocation of node IDs does not work across + multiple management servers. + </para> + </listitem> + + <listitem> + <para> + You must take extreme care to have the same configurations + for all management servers. No special checks for this are + performed by the cluster. + </para> + </listitem> + + </itemizedlist> + </para> + + </formalpara> + + <itemizedlist> + + <listitem> + <formalpara> + + <title>Multiple network addresses</title> + + <para> + Multiple network addresses per data node are not supported. + Use of these is liable to cause problems: In the event of a + data node failure, an SQL node waits for confirmation that + the data node went down but never receives it because + another route to that data node remains open. This can + effectively make the cluster inoperable. + </para> + + </formalpara> + + <para> + It is possible to use multiple network hardware + <emphasis>interfaces</emphasis> (such as Ethernet cards) for a + single data node, but these must be bound to the same address. + This also means that it not possible to use more than one + <literal>[TCP]</literal> section per connection in the + <literal>config.ini</literal> file. See + <xref linkend="mysql-cluster-tcp-definition"/>, for more + information. + </para> + </listitem> + + </itemizedlist> + </section> - + <section id="mysql-cluster-limitations-resolved"> + <title>Previous MySQL Cluster Issues Resolved in MySQL 5.1</title> - + <indexterm> <primary>MySQL Cluster limitations</primary> <secondary>resolved in current version from previous versions</secondary> @@ -1181,213 +1272,229 @@ A number of limitations and related issues existing in earlier versions of MySQL Cluster have been resolved over the course of development of MySQL ¤t-series; or &mccge-series;: - + <itemizedlist> - - <listitem> - <para> - The <literal>NDB Cluster</literal> storage engine now - supports variable-length column types for in-memory - tables. - </para> - - <para> - Previously, for example, any Cluster table having one or more - <literal>VARCHAR</literal> fields which contained only - relatively small values, much more memory and disk space - were required when using the <literal>NDBCLUSTER</literal> - storage engine than would have been the case for the same - table and data using the <literal>MyISAM</literal> engine. - In other words, in the case of a - <literal>VARCHAR</literal> column, such a column required - the same amount of storage as a <literal>CHAR</literal> - column of the same size. In MySQL 5.1, this is no longer - the case for in-memory tables, where storage requirements - for variable-length column types such as - <literal>VARCHAR</literal> and <literal>BINARY</literal> - are comparable to those for these column types when used - in <literal>MyISAM</literal> tables (see - <xref linkend="storage-requirements"/>). - </para> - - <important> + + <listitem> <para> - For MySQL Cluster Disk Data tables, the fixed-width - limitation continues to apply. See - <xref linkend="mysql-cluster-disk-data"/>. + The <literal>NDB Cluster</literal> storage engine now + supports variable-length column types for in-memory tables. </para> - </important> - </listitem> - - <listitem> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>replication</secondary> - </indexterm> - - <para> - It is now possible to use MySQL replication with Cluster - databases. For details, see - <xref linkend="mysql-cluster-replication"/>. - </para> - - <para> - However, circular replication is <emphasis>not</emphasis> - currently supported for MySQL Cluster. See - <xref linkend="mysql-cluster-replication-issues"/>. - </para> - </listitem> - - <listitem> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>autodiscovery</secondary> - </indexterm> - - <para> - Autodiscovery of databases is now supported for multiple - MySQL servers accessing the same MySQL Cluster, provided - that a given <command>mysqld</command> is already running - and is connected to the cluster at the time that the - database is created on a different - <command>mysqld</command>. - </para> - - <para> - What this means is that if a <command>mysqld</command> - process first connects to the cluster after a database - named <replaceable>db_name</replaceable> has been created, - you should issue a <literal>CREATE SCHEMA - <replaceable>db_name</replaceable></literal> statement on - the <quote>new</quote> MySQL server when it first accesses - that MySQL Cluster. Once this has been done, the - <quote>new</quote> <command>mysqld</command> should be - able to detect any tables in that database tables without - errors. - </para> - - <para> - This also means that online schema changes in - <literal>NDB</literal> tables are now possible. That is, - the result of operations such as <literal>ALTER - TABLE</literal> and <literal>CREATE INDEX</literal> - performed on one SQL node in the cluster are now visible - to the cluster's other SQL nodes without any additional - action being taken. - </para> - </listitem> - - <listitem> - <para> - Beginning with MySQL 5.1.10, it is possible to perform a - Cluster backup and restore between different - architectures. Previously — for example — you - could not back up a cluster running on a big-endian - platform and then restore from that backup to a cluster - running on a little-endian system. (Bug #19255) - </para> - </listitem> - - <listitem> - <formalpara> - <title>Character sets</title> - + + <para> + Previously, for example, any Cluster table having one or + more <literal>VARCHAR</literal> fields which contained only + relatively small values, much more memory and disk space + were required when using the <literal>NDBCLUSTER</literal> + storage engine than would have been the case for the same + table and data using the <literal>MyISAM</literal> engine. + In other words, in the case of a <literal>VARCHAR</literal> + column, such a column required the same amount of storage as + a <literal>CHAR</literal> column of the same size. In MySQL + 5.1, this is no longer the case for in-memory tables, where + storage requirements for variable-length column types such + as <literal>VARCHAR</literal> and <literal>BINARY</literal> + are comparable to those for these column types when used in + <literal>MyISAM</literal> tables (see + <xref linkend="storage-requirements"/>). + </para> + + <important> + <para> + For MySQL Cluster Disk Data tables, the fixed-width + limitation continues to apply. See + <xref linkend="mysql-cluster-disk-data"/>. + </para> + </important> + </listitem> + + <listitem> <indexterm> <primary>MySQL Cluster limitations</primary> - <secondary>character sets</secondary> + <secondary>replication</secondary> </indexterm> - <para> - Beginning with MySQL 5.1.10, it is possible to install - MySQL with Cluster support to a non-default location and - change the search path for font description files using - either the <option>--basedir</option> or - <option>--character-sets-dir</option> options. - (Previously, <command>ndbd</command> in MySQL 5.1 searched - only the default path — typically - <filename>/usr/local/mysql/share/mysql/charsets</filename> - — for character sets.) - </para></formalpara> - </listitem> - - <listitem> - <para> - In MySQL 5.1, it is no longer necessary, when running - multiple management servers, to restart all the cluster's - data nodes to enable the management nodes to see one - another. - </para> - </listitem> - - - <listitem> - <formalpara> - <title>Length of <literal>CREATE TABLE</literal> statements</title> - + + <para> + It is now possible to use MySQL replication with Cluster + databases. For details, see + <xref linkend="mysql-cluster-replication"/>. + </para> + + <para> + However, circular replication is <emphasis>not</emphasis> + currently supported for MySQL Cluster. See + <xref linkend="mysql-cluster-replication-issues"/>. + </para> + </listitem> + + <listitem> <indexterm> <primary>MySQL Cluster limitations</primary> - <secondary>CREATE TABLE statements</secondary> + <secondary>autodiscovery</secondary> </indexterm> + <para> - <literal>CREATE TABLE</literal> statements may be no more - than 4096 characters in length. <emphasis>This limitation + Autodiscovery of databases is now supported for multiple + MySQL servers accessing the same MySQL Cluster, provided + that a given <command>mysqld</command> is already running + and is connected to the cluster at the time that the + database is created on a different + <command>mysqld</command>. + </para> + + <para> + What this means is that if a <command>mysqld</command> + process first connects to the cluster after a database named + <replaceable>db_name</replaceable> has been created, you + should issue a <literal>CREATE SCHEMA + <replaceable>db_name</replaceable></literal> statement on + the <quote>new</quote> MySQL server when it first accesses + that MySQL Cluster. Once this has been done, the + <quote>new</quote> <command>mysqld</command> should be able + to detect any tables in that database tables without errors. + </para> + + <para> + This also means that online schema changes in + <literal>NDB</literal> tables are now possible. That is, the + result of operations such as <literal>ALTER TABLE</literal> + and <literal>CREATE INDEX</literal> performed on one SQL + node in the cluster are now visible to the cluster's other + SQL nodes without any additional action being taken. + </para> + </listitem> + + <listitem> + <para> + Beginning with MySQL 5.1.10, it is possible to perform a + Cluster backup and restore between different architectures. + Previously — for example — you could not back up + a cluster running on a big-endian platform and then restore + from that backup to a cluster running on a little-endian + system. (Bug #19255) + </para> + </listitem> + + <listitem> + <formalpara> + + <title>Character sets</title> + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>character sets</secondary> + </indexterm> + + <para> + Beginning with MySQL 5.1.10, it is possible to install + MySQL with Cluster support to a non-default location and + change the search path for font description files using + either the <option>--basedir</option> or + <option>--character-sets-dir</option> options. + (Previously, <command>ndbd</command> in MySQL 5.1 searched + only the default path — typically + <filename>/usr/local/mysql/share/mysql/charsets</filename> + — for character sets.) + </para> + + </formalpara> + </listitem> + + <listitem> + <para> + In MySQL 5.1, it is no longer necessary, when running + multiple management servers, to restart all the cluster's + data nodes to enable the management nodes to see one + another. + </para> + </listitem> + + <listitem> + <formalpara> + + <title>Length of <literal>CREATE TABLE</literal> statements</title> + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>CREATE TABLE statements</secondary> + </indexterm> + + <para> + <literal>CREATE TABLE</literal> statements may be no more + than 4096 characters in length. <emphasis>This limitation affects MySQL 5.1.6, 5.1.7, and 5.1.8 only</emphasis>. - (See Bug #17813) - </para></formalpara> - </listitem> - - <listitem> - <formalpara> - <title><literal>IGNORE</literal> and <literal>REPLACE</literal> functionality</title> - <indexterm> - <primary>MySQL Cluster limitations</primary> - <secondary>INSERT IGNORE, UPDATE IGNORE, and REPLACE statements</secondary> - </indexterm> - <para> - In MySQL 5.1.7 and earlier, <literal>INSERT - IGNORE</literal>, <literal>UPDATE IGNORE</literal>, and - <literal>REPLACE</literal> were supported only for primary - keys, but not for unique keys. It was possible to work around - this issue by removing the constraint, then dropping the unique index, - performing any inserts, and then adding the unique index again. - </para></formalpara> - - <para> - This limitation was removed for <literal>INSERT + (See Bug #17813) + </para> + + </formalpara> + </listitem> + + <listitem> + <formalpara> + + <title><literal>IGNORE</literal> and <literal>REPLACE</literal> functionality</title> + + <indexterm> + <primary>MySQL Cluster limitations</primary> + <secondary>INSERT IGNORE, UPDATE IGNORE, and REPLACE statements</secondary> + </indexterm> + + <para> + In MySQL 5.1.7 and earlier, <literal>INSERT + IGNORE</literal>, <literal>UPDATE IGNORE</literal>, and + <literal>REPLACE</literal> were supported only for primary + keys, but not for unique keys. It was possible to work + around this issue by removing the constraint, then + dropping the unique index, performing any inserts, and + then adding the unique index again. + </para> + + </formalpara> + + <para> + This limitation was removed for <literal>INSERT IGNORE</literal> and <literal>REPLACE</literal> in MySQL - 5.1.8. (See Bug #17431.) - </para> - </listitem> - - <listitem> - <formalpara> - <title><literal>AUTO_INCREMENT</literal> columns</title> - <para> - In MySQL 5.1.10 and earlier versions, the maximum number - of tables having <literal>AUTO_INCREMENT</literal> columns - — including those belonging to hidden primary keys - — was 2048. - </para> - </formalpara> - - <para> - This limitation was lifted in MySQL 5.1.11. - </para> - </listitem> - + 5.1.8. (See Bug #17431.) + </para> + </listitem> + <listitem> + <formalpara> + + <title><literal>AUTO_INCREMENT</literal> columns</title> + + <para> + In MySQL 5.1.10 and earlier versions, the maximum number + of tables having <literal>AUTO_INCREMENT</literal> columns + — including those belonging to hidden primary keys + — was 2048. + </para> + + </formalpara> + + <para> + This limitation was lifted in MySQL 5.1.11. + </para> + </listitem> + + <listitem> &mccge-warning-begin; <formalpara> - <title>Maximum number of cluster nodes</title> + + <title>Maximum number of cluster nodes</title> + + <para> + Prior to MySQL 5.1.15-ndb-6.1.1, the total maximum number + of nodes in a MySQL Cluster was 63, including all SQL + nodes (MySQL Servers), API nodes (applications accessing + the cluster other than MySQL servers), data nodes, and + management servers. + </para> + + </formalpara> + <para> - Prior to MySQL 5.1.15-ndb-6.1.1, the total maximum number - of nodes in a MySQL Cluster was 63, including all SQL - nodes (MySQL Servers), API nodes (applications accessing - the cluster other than MySQL servers), data nodes, and - management servers. - </para> - </formalpara> - <para> Starting with MySQL 5.1.15-ndb-6.1.1, up to 255 API nodes (including MySQL servers acting as cluster SQL nodes) are supported by a single cluster. The total number of data @@ -1397,15 +1504,10 @@ &mccge-warning-end-cluster; </listitem> - - </itemizedlist> - </para> - - - + </itemizedlist> + </para> - + </section> - </section> -</section> \ No newline at end of file +</section>
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| • svn commit - mysqldoc@docsrva: r6518 - trunk/refman-5.1 | jon | 18 May |
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