MySQL Community Server 5.6.21がリリースされました

最も普及しているオープンソースデータベース管理システムの新バージョンMySQL Community Server 5.6.21がリリースされました。


     Starting with 5.6.11, Microsoft Windows packages for MySQL 5.6
     are available both as a "full" installer and as a "web" installer.
     The full installer is significantly larger and comes bundled with
     the latest software releases available. This bundle makes it easy
     to download and configure a full server and development suite.

     The web installer doesn't come bundled with any actual products
     and instead relies on download-on-demand to fetch only the
     products you choose to install. This makes the initial download
     much smaller but increases install time as the individual products
     will need to be downloaded.

For information on installing MySQL 5.6.21 on new servers or upgrading
to MySQL 5.6.21 from previous MySQL releases, please see


MySQL Server is available in source and binary form for a number of
platforms from our download pages at


Not all mirror sites may be up to date at this point in time, so if you
can't find this version on some mirror, please try again later or choose
another download site.

We welcome and appreciate your feedback, bug reports, bug fixes,
patches, etc:


The following section lists the changes in the MySQL 5.6 since
the release of MySQL 5.6.20. It may also be viewed
online at



Changes in MySQL 5.6.21 (2014-09-23)

    InnoDB Notes

      * The --skip-innodb option is now deprecated and its use results
        in a warning. It will be removed in a future MySQL release.
        This also applies to its synonyms (--innodb=OFF,
        --disable-innodb, and so forth).

    MySQL Enterprise Notes

      * MySQL Enterprise Edition now includes a set of encryption
        functions based on the OpenSSL library that expose OpenSSL
        capabilities at the SQL level. These functions enable
        Enterprise applications to perform the following operations:

           + Implement added data protection using public-key
             asymmetric cryptography

           + Create public and private keys and digital signatures

           + Perform asymmetric encryption and decryption

           + Use cryptographic hashing for digital signing and data
             verification and validation
        For more information, see MySQL Enterprise Encryption

    Functionality Added or Changed

      * Internally, spatial data types such as Geometry are
        represented as BLOB values, so when invoked with the
        --hex-blob option, mysqldump now displays spatial values in
        hex. (Bug #43544, Bug #11752369)

    Bugs Fixed

      * InnoDB; Partitioning: Large numbers of partitioned InnoDB
        tables could consume much more memory when used in MySQL 5.6
        or 5.7 than the memory used by the same tables used in
        previous releases of the MySQL Server. (Bug #17780517, Bug
        References: This bug was introduced by Bug #11764622, Bug

      * InnoDB: An ALTER TABLE ... ADD FOREIGN KEY operation could
        cause a serious error. (Bug #19471516, Bug #73650)

      * InnoDB: In debug builds, an INSERT operation affecting
        compressed tables would raise a sync-related assertion. (Bug

      * InnoDB: Retrieval of multiple values with a single get command
        would return incorrect results instead of an error message.
        The InnoDB memcached plugin does not currently support
        retrieval of multiple values with a single get command. (Bug
        #19172212, Bug #72453)

      * InnoDB: Attempting to perform operations on a timed out key
        would cause the memcached daemon to crash and restart. (Bug
        #19172013, Bug #72586)

      * InnoDB: With a transaction isolation level less than or equal
        to READ COMMITTED, gap locks were not taken when scanning a
        unique secondary index to check for duplicates. As a result,
        duplicate check logic failed allowing duplicate key values in
        the unique secondary index. (Bug #19140907)
        References: This bug is a regression of Bug #16133801.

      * InnoDB: In rare cases, the purge process would attempt to
        delete a secondary index record that was not marked for
        deletion, resulting in an inconsistent secondary index. (Bug

      * InnoDB: During recovery, a segmentation fault would occur when
        marking a table as corrupt. (Bug #18942294)

      * InnoDB: A failed in-place ALTER TABLE operation would leave
        behind non-unique temporary file names in the data dictionary
        preventing future ALTER TABLE operations on the same table due
        to temporary file name conflicts. To avoid this problem,
        temporary file names are made unique by appending a static
        global number that is initialized to a random distributed
        32-bit number using ut_time() and ut_crc32(). The number is
        then incremented atomically for each assigned temporary file
        name. Previously, temporary files were named using the format
        #sql-ibtid, where tid is the table ID. Temporary files are now
        named using the format #sql-ibtid-inc, where tid is the table
        ID and inc is the incremented number. (Bug #18734396, Bug

      * InnoDB: srv_active_wake_master_thread() was called directly in
        innobase_commit and innobase_prepare, waking up the master
        thread and incrementing srv_activity_count.
        srv_active_wake_master_thread() should only be called after
        committing write transactions, not after read-only
        transactions or rollbacks. This patch also replaces some calls
        to srv_active_wake_master_thread() with calls to
        ib_wake_master_thread(). (Bug #18477009, Bug #72137)

      * InnoDB: An in-place ALTER TABLE operation on a table with a
        broken foreign key constraint could raise an assertion. (Bug

      * InnoDB: Inserting a record into an InnoDB table with a key
        that falls between the maximum key of a full page and the
        minimum key of the "next" page could result in unnecessary
        page splits and under-filled pages. If the insert point is at
        the end of a page, InnoDB now attempts to insert to the next
        page before splitting the page. (Bug #15923864, Bug #67718)

      * Replication: After the fix for Bug #16861624, killing a
        multi-threaded slave worker which was waiting for a commit
        lock caused a debug assertion to fail. This fix ensures that
        such a situation can not occur. (Bug #19311260)

      * Replication: When committing a transaction, a flag is now used
        to check whether a thread has been created, rather than
        checking the thread itself, which uses more resources,
        particularly when running the server with
        master_info_repository=TABLE. (Bug #18684222)
        References: See also Bug #17967378.

      * Replication: A multi-threaded slave now checks that a free
        worker is available to dispatch the next event. In previous
        versions, a multi-threaded slave crashes with a worker error
        if the thread coordinator can not find a free worker. The
        crash was caused when the coordinator did not return a free
        worker, for example if the coordinator was aborted at the same
        time using STOP SLAVE. (Bug #18363515)

      * Replication: When mysqlbinlog processed multiple binary log
        files into a single output file, this file was not in a useful
        state for point-in-time recovery, when it failed with the
        error, When @@SESSION.GTID_NEXT is set to a GTID, you must
        explicitly set it to a different value after a COMMIT or
        ROLLBACK. Please check GTID_NEXT variable manual page for
        detailed explanation. Current @@SESSION.GTID_NEXT is 'xyz'.
        When mysqlbinlog processes a binary log containing GTIDs, it
        outputs SET gtid_next statements, but gtid_next is set to
        undefined whenever a commit occurs; this left gtid_next
        undefined when the server had finished processing the output
        from mysqlbinlog. When the next binary log file started with
        one or more anonymous statements or transactions, the
        combination of gtid_next being left undefined at the end of
        the first binary log and the second binary log containing
        anonymous transactions to the error described previously
        To fix this issue, now, whenever mysqlbinlog encounters this
        situation, it inserts SET gtid_next = AUTOMATIC if required to
        avoid leaving the previous binary log with gtid_next
        In addition, as a result of this fix, mysqlbinlog no longer
        outputs session variable information for every binary log;
        now, this value is printed only once unless it changes. (Bug
        #18258933, Bug #71695)

      * Replication: When the I/O thread reconnected to a master using
        GTIDs and multithreaded slaves while in the middle of a
        transaction, it failed to abort the transaction, leaving a
        partial transaction in the relay log, and then retrieving the
        same transaction again. This occurred when performing a
        rotation of the relay log. Now when reconnecting, the server
        checks before rotating the log in such cases, and waits first
        for any ongoing transaction to complete. (Bug #17326020)

      * Replication: When using semisynchronous replication, if the
        binary log position was changed to a future position on a
        slave then an assertion error was generated on the master.
        This fix ensures that in such a situation the future position
        is correctly acknowledged and an error is instead generated on
        the slave. (Bug #70327, Bug #17453826)

      * Replication: When an SQL thread which was waiting for a commit
        lock was killed and restarted it caused a transaction to be
        skipped on slave. This fix ensures that thread positions are
        correctly persisted and transactions resume at the correct
        position. (Bug #69873, Bug #17450876)

      * Replication: On a master that is using semisynchronous
        replication, where rpl_semi_sync_master_wait_no_slave is
        enabled and rpl_semi_sync_master_timeout is set to long
        timeout, killing the I/O thread could cause the server to hang
        on shutdown. This fix ensures that if the dump thread finds
        that there no semisynchronous slaves connected to the master,
        the setting of rpl_semi_sync_master_wait_no_slave is ignored
        and the shutdown proceeds correctly. (Bug #71047, Bug

      * Replication: When using row-based replication, setting a
        slave's slave_rows_search_algorithms variable to HASH_SCAN
        caused an ER_RECORD_NOT_FOUND error even though that record
        existed in the storage layer. This fix ensures that the unique
        key for each record is correctly maintained and such a
        situation does not occur. (Bug #72788, Bug #18860225)

      * Replication: When an event group was spanned across multiple
        relay log files, a slave could incorrectly identify
        GTID-header group boundaries. This meant that when a
        transaction was retried, or if the SQL thread was stopped in
        the middle of a transaction after some rotates, the
        Gtid_log_event was being silently skipped on the slave, and
        the transaction was logged with the slave's GTID. This problem
        also impacted on using START SLAVE UNTIL MASTER_LOG_POS =
        log_pos; with GTIDs enabled. If log_pos was in the middle of a
        transaction, the Gtid_log_event was not correctly detected as
        the beginning of the transaction and replication stopped
        before this event. With this fix, threads correctly detect
        that they are part of a group, and this is used to check if a
        Gtid_log_event is part of a transaction. (Bug #72313, Bug
        #18652178, Bug #18306199)

      * Replication: The error messages generated when a duplicate
        server UUID causes issues during replication have been
        improved. The slave error now identifies the duplicate server
        UUID and the master error identifies the zombie thread that
        has been killed. (Bug #72578, Bug #18731211)

      * Replication: The CLIENT_REMEMBER_OPTIONS flag for compressed
        slave connections is no longer reset and all options are
        retained. This restores functionality of all options to
        compressed slave connections. (Bug #72901, Bug #18923691, Bug
        #73324, Bug #19244772)

      * Replication: When using row-based replication, running a long
        transaction involving a large number of events could trigger
        an Out of Memory (OOM) error if the slave's table structure
        was not compatible with the master's table structure. Such an
        incompatible situation could occur if the table on the slave
        had been manually changed, or when replicating between
        different MySQL versions that have different data types. This
        OOM error was caused because the virtual temporary tables
        created for the row conversion were not being freed until the
        end of the transaction, which was a problem when replicating
        large numbers of events.
        Starting with this version, such virtual tables are correctly
        freed during the conversion process. (Bug #72610, Bug

      * With DTrace support enabled, certain other compilation options
        could cause the build to fail. (Bug #19506247)

      * yaSSL could fail preauthorization if the client supplied
        inaccurate buffer lengths. (Bug #19370676, Bug #19355577)

      * Competition between threads could lead to timeout failure
        trying to rotate the audit log file. (Bug #19184973)

      * LPAD() and RPAD() could cause a server exit if the pad string
        argument was not well formed. (Bug #18935421)

      * The optimizer could create a zero-length column for a
        temporary table, causing a server exit. (Bug #18928848)

      * MOD for very small decimal right-hand arguments could cause a
        server exit. (Bug #18469276)

      * The client library now includes a call to
        X509_verify_cert_error_string() in the SSL certificate
        verification code, to be more robust in detecting invalid
        certificates. (Bug #18384260)

      * If the left-hand-side of an IN predicate was a scalar subquery
        but returned no row, the server could exit. (Bug #18223655,
        Bug #18447874)

      * The thread_concurrency system variable is deprecated, but no
        warning resulted from setting it at server startup. (Bug

      * Sending a SIGQUIT or SIGINT signal to mysql could result in a
        glibc double free or corruption error. (Bug #17297324)

      * Invalid memory access could occur when using prepared
        statements if a mysql client connection was lost after
        statement preparation was complete and there was at least one
        statement that was in initialized state but not prepared yet.
        (Bug #70429, Bug #17512527)

      * LIKE matches failed for code points of HALF WIDTH KATAKANA in
        the sjis and cp932 character sets. (Bug #47641, Bug #11755818)

      * On EL7, installation of MySQL from RPM packages could fail if
        postfix had previously been installed using yum. (Bug #73507,
        Bug #19392051, Bug #19392149)

      * mysql_upgrade could fail if the mysql.user table contained
        multiple accounts with the same user name and host name where
        the host name differed in lettercase. This is still not
        permitted, but now mysql_upgrade prints a more informative
        error message to indicate the nature of the problem:
        ERROR 1644 (45000): Multiple accounts exist for user_name,
        host_name that differ only in Host lettercase; remove all
        except one of them (Bug #72066, Bug #18415196)

      * If the general query log or slow query log file was set to a
        FIFO or socket file, and the file reader went away, the server
        stopped executing statements. Now the server detects such
        files, logs an error message, and continues with the
        appropriate log disabled. (Bug #67088, Bug #14757009)

      * A simultaneous OPTIMIZE TABLE and online ALTER TABLE on the
        same InnoDB table could result in deadlock. (Bug #71433, Bug

      * The query cache was not invalidated for a table when a CASCADE
        DELETE or CASCADE UPDATE referential constraint was specified
        and the database name or table name contained special
        characters. (Bug #72547, Bug #18710853)