MySQL 5.5.23 がリリースされました


MySQL 5.5.23は世界でもっともポピュラーなオープンソースデータベースの5.5のプロダクトリリースの新しいバージョンです。MySQL 5.5.23はプロダクションシステムでの使用をお勧めします。

MySQL 5.5は最新のマルチCPUやマルチコアハードウェアやオペレーティングシステムの利点を生かし、MySQLデータベースのパフォーマンスとスケーラビリ ティを改善するための影響の大きい変更をいくつか含んでいます。現在ではInnoDBがMySQLデータベースのデフォルトのストレージエンジンであり、 ACIDトランザクション、参照整合性、クラッシュリカバリをデフォルトで提供しています。

MySQL 5.5は以下の多くの新しい強化も含んでいます:

   - Windowsにおける特有の機能と改善を利用した著しいパフォーマンス向上
   - 新しい準同期レプリケーションとレプリケーションハートビートによるより高いレベルの可用性
   - 改善されたインデックスとテーブルパーティショニング、SIGNAL/RESIGNALサポート、そして新しいPERFORMANCE_SCHEMAに含まれる強化された診断法による改善されたユーザビリティ

MySQL 5.5の新機能のより完全な概観については、以下のリソースを参照下さい。

MySQL 5.5 GA、Tomas Ulinのインタビュー:




ホワイトペーパー: MySQL 5.5の新機能


製品レベルのシステムでMySQLを稼動させているならば、MySQL製品、バックアップ、モニタリング、モデリング、開発、管理ツールの包括的なセット を含むMySQLパフォーマンス、セキュリティ、アップタイムの高いレベルを実現するMySQL Enterprise Editionの製品詳細に注目してください。


新しいサーバへMySQL 5.5.23をインストールする情報として、以下のMySQLのインストールドキュメントを参照してください。





MySQL Server 5.5は、http://dev.mysql.com/downloads/とミラーサイトのダウンロード・ページから、ソースコード及び多くのプラットフォームのためのバイナリで現在利用可能です。




次の節では、MySQL 5.5の以前のバージョンからのMySQLソースコードの変更を記載しています。これはオンラインでも閲覧できます。

Changes in MySQL 5.5.23 (12 April 2012)

Functionality Added or Changed

   * The MySQL-shared-compat RPM package enables users of Red
     Hat-privided mysql-*-5.1 RPM packages to migrate to
     Oracle-provided MySQL-*-5.5 packages. MySQL-shared-compat now
     replaces the Red Hat mysql-libs package by replacing
     libmysqlclient.so files of the latter package, thus satisfying
     dependencies of other packages on mysql-libs. This change
     affects only users of Red Hat (or Red Hat-compatible) RPM
     packages. Nothing is different for users of Oracle RPM
     packages. (Bug #13867506)

Bugs Fixed

   * Security Fix: Bug #59533 was fixed.

   * Performance: Partitioning: InnoDB Storage Engine: The
     statistics used by the optimizer for queries against
     partitioned InnoDB tables were based only on the first
     partition of each such table, leading to use of the wrong
     execution plan. (Bug #13694811)
     References: This bug was introduced by Bug #11756867.

   * Performance: InnoDB Storage Engine: Improved the performance
     of the DROP TABLE statement for InnoDB tables, especially on
     systems with a large buffer pool. The fix speeds up the
     processing for freeing entries in the adaptive hash index.
     (Bug #13704145, Bug #64284)

   * InnoDB Storage Engine: Deleting a huge amount of data from
     InnoDB tables within a short time could cause the purge
     operation that flushes data from the buffer pool to stall. If
     this issue occurs, restart the server to work around it. This
     issue is only likely to occur on 32-bit platforms. (Bug

   * InnoDB Storage Engine: If the server crashed during a TRUNCATE
     TABLE or CREATE INDEX statement for an InnoDB table, or a DROP
     DATABASE statement for a database containing InnoDB tables, an
     index could be corrupted, causing an error message when
     accessing the table after restart:
      InnoDB: Error: trying to load index index_name for table
      InnoDB: table_name but the index tree has been freed!
     In MySQL 5.1, this fix applies to the InnoDB Plugin, but not
     the built-in InnoDB storage engine. (Bug #12861864, Bug

   * InnoDB Storage Engine: When data was removed from an InnoDB
     table, newly inserted data might not reuse the freed disk
     blocks, leading to an unexpected size increase for the system
     tablespace or .ibd file (depending on the setting of
     innodb_file_per_table. The OPTIMIZE TABLE could compact a .ibd
     file in some cases but not others. The freed disk blocks would
     eventually be reused as additional data was inserted. (Bug
     #11766634, Bug #59783)

   * Partitioning: After updating a row of a partitioned table and
     selecting that row within the same transaction with the query
     cache enabled, then performing a ROLLBACK, the same result was
     returned by an identical SELECT issued in a new transaction.
     (Bug #11761296, Bug #53775)

   * Replication: Formerly, the default value shown for the Port
     column in the output of SHOW SLAVE HOSTS was 3306 whether the
     port had been set incorrectly or not set at all. Now, when the
     slave port is not set, 0 is used as the default. This change
     also affects the default used for the --report-port server
     option. (Bug #13333431)

   * Replication: The --relay-log-space-limit option was sometimes
     More specifically, when the SQL thread went to sleep, it
     allowed the I/O thread to queue additional events in such a
     way that the relay log space limit was bypassed, and the
     number of events in the queue could grow well past the point
     where the relay logs needed to be rotated. Now in such cases,
     the SQL thread checks to see whether the I/O thread should
     rotate and provide the SQL thread a chance to purge the logs
     (thus freeing space).
     Note that, when the SQL thread is in the middle of a
     transaction, it cannot purge the logs; it can only ask for
     more events until the transaction is complete. Once the
     transaction is finished, the SQL thread can immediately
     instruct the I/O thread to rotate. (Bug #12400313, Bug #64503)
     References: See also Bug #13806492.

   * An infinite thread loop could develop within Performance
     Schema, causing the server to become unresponsive. (Bug

   * Incorrect stored program caching could cause statements within
     a stored program that included a GROUP BY clause to return
     different results across multiple program invocations. (Bug

   * Mishandling of NO_BACKSLASH_ESCAPES SQL mode within stored
     procedures on slave servers could cause replication failures.
     (Bug #12601974)

   * SAVEPOINT statements were incorrectly disallowed within XA
     transactions. (Bug #64374, Bug #13737343)
     References: See also Bug #11766752.

   * The Performance Schema incorrectly displayed some backslashes
     in Windows file names (by doubling them). (Bug #63339, Bug

   * SHOW statements treated stored procedure, stored function, and
     event names as case sensitive. (Bug #56224, Bug #11763507)