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From:karen langford Date:August 1 2014 11:20pm
Subject:MySQL Community Server 5.6.20 has been released
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Dear MySQL users,

MySQL Server 5.6.20, a new version of the popular Open Source
Database Management System, has been released. MySQL 5.6.20 is
recommended for use on production systems.

For an overview of what's new in MySQL 5.6, please see

     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 5.6.20 on new servers or upgrading
to MySQL 5.6.20 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 source code since
the previous released version of MySQL 5.6. It may also be viewed
online at


Changes in MySQL 5.6.20 (2014-07-31)

    Security Notes

      * Security Fix: The linked OpenSSL library for the MySQL 5.6
        Commercial Server has been updated from version 1.0.1g to
        version 1.0.1h. Versions of OpenSSL prior to and including
        1.0.1g are reported to be vulnerable to CVE-2014-0224
        This change does not affect the Oracle-produced MySQL
        Community build of MySQL Server 5.6, which uses the yaSSL
        library instead. (CVE-2014-0224)

    InnoDB Notes

      * Important Change: Redo log writes for large, externally stored
        BLOB fields could overwrite the most recent checkpoint. The
        5.6.20 patch limits the size of redo log BLOB writes to 10% of
        the redo log file size. The 5.7.5 patch addresses the bug
        without imposing a limitation. For MySQL 5.5, the bug remains
        a known limitation.
        As a result of the redo log BLOB write limit introduced for
        MySQL 5.6, innodb_log_file_size should be set to a value
        greater than 10 times the largest BLOB data size found in the
        rows of your tables plus the length of other variable length
        fields (VARCHAR, VARBINARY, and TEXT type fields). Failing to
        do so could result in "Row size too large" errors. No action
        is required if your innodb_log_file_size setting is already
        sufficiently large or your tables contain no BLOB data. (Bug
        #16963396, Bug #19030353, Bug #69477)

    Functionality Added or Changed

      * Replication: The new system variable binlog_impossible_mode
        controls what happens if the server cannot write to the binary
        log, for example, due to a file error. For backward
        compatibility, the default for binlog_impossible_mode is
        IGNORE_ERROR, meaning the server logs the error, halts
        logging, and continues updates to the database. Setting this
        variable to ABORT_SERVER makes the server halt logging and
        shut down the server if it can not write to the binary log.
        (Bug #51014, Bug #11758766)

      * CMake support was updated to handle CMake version 3. (Bug

      * New Debian7, Ubuntu12.04, and Ubuntu14.04 distribution support
        that was introduced with 5.6.17 now comes with the
        platform-specific packaging source placed under the packaging
        directory, in the deb-precise, deb-wheezy, and deb-trusty
        directories. (Bug #19020385)

      * Support for LinuxThreads has been removed from the source
        code. LinuxThreads was superseded by NPTL in Linux 2.6. (Bug
        #17007529, Bug #72888, Bug #18913935)

      * By default, mysql_install_db creates a my.cnf file in the
        installation base directory using a template. This may be
        undesireable for some deployments. To enable this behavior to
        be suppressed, mysql_install_db now supports a --keep-my-cnf
        option to preserve any existing my.cnf file and not create a
        new my.cnf file. (Bug #71600, Bug #18205019)

      * The mysqlhotcopy utility is now deprecated and will be removed
        in a future version of MySQL. Among the reasons for this: It
        works only for the MyISAM and ARCHIVE storage engines; it
        works on Unix but not Windows. Alternatives include mysqldump
        and MySQL Enterprise Backup.

      * The timed_mutexes system variable has no effect and is

    Bugs Fixed

      * Important Change; Replication: A DROP TABLE statement may be
        divided into multiple statements before it is sent to the
        binary log if it contains regular (not temporary) tables and
        temporary tables, or if it contains temporary tables using
        both transactional and non-transactional storage engines. Now,
        when using GTIDs, DROP TABLE statements affecting these
        combinations of tables are no longer allowed unless the value
        of the gtid_next system variable is AUTOMATIC. This is
        because, with GTIDs enabled on the server, issuing a DROP
        TABLE in the cases just described while having only one GTID
        associated with each statement (the SQL thread does this
        following SET gtid_next='uuid:number') causes problems when
        there are not enough GTIDs for assignment to all the resulting
        statements following the division of the original DROP TABLE.
        A DROP TABLE statement might be split due to the behavior of
        the statement with respect to the current transaction varying,
        depending on table characteristics, as follows:

           + DROP TABLE of a regular (not temporary) table is
             committed immediately

           + DROP TABLE of a temporary table using a transactional
             storage engine is committed with the current transaction
             (following COMMIT)

           + DROP TABLE of a temporary table that uses a
             nontransactional storage engine is committed immediately
        Naming all three of these types of tables in a single DROP
        TABLE statement causes the MySQL server to divide the original
        statement into three separate DROP TABLE statements in the
        binary log. If GTIDs are enabled but the value of gtid_next is
        not AUTOMATIC, issuing a DROP TABLE statement that mixes any
        of the table types described previously causes the server to
        have an insufficient number of GTIDs to write with all of the
        resulting statements into the binary log. In addition, DROP
        TABLE IF EXISTS is always written in the binary log for all
        tables specified in the statement, even if some or all of the
        tables do not exist.
        Because temporary tables are handled differently by DROP TABLE
        depending on whether they use a transactional or
        nontransactional storage engine, any tables named by a DROP
        TEMPORARY TABLE statement that do not exist are assumed to be
        transactional. This means that, if a DROP TEMPORARY TABLE with
        two nontransactional temporary tables is issued on the master,
        it would writes only one DROP TABLE statement naming both
        tables. If one of the temporary tables no longer exists on the
        slave, then, when the SQL thread executes the statement, it
        tries to divide it into multiple statements due to it
        affecting a nontransactional (but existing) temporary table
        and a nonexistent transactional temporary table; this leads to
        problems because the SQL thread has only one GTID for the
        original DROP TABLE statement but must write two DROP TABLE
        statements in the binary log.
        In addition, when the slave dropped temporary tables after
        detecting that the master had restarted, it logged one DROP
        TABLE statement per pseudo-thread and per database, but
        combined temporary tables using transactional and
        nontransactional storage engines in a single DROP TABLE
        Now, we throw an error in the client session if gtid_next is
        set to a uuid:number value and a DROP TABLE statement is
        issued mixing any of the table types described previously.
        In addition, we now group the nonexistent temporary tables and
        assume them to be transactional only if at least one
        transactional temporary table is dropped by the statement. If
        no transactional temporary tables are dropped, any nonexistent
        temporary tables are assumed to be nontransactional temporary
        The slave now also handles dropping of temporary tables
        correctly in the event of the restart by the master. (Bug

      * InnoDB: Opening a parent table that has thousands of child
        tables could result in a long semaphore wait condition. (Bug

      * InnoDB: For single item full-text searches, deleted documents
        were included in inverse document frequency (IDF)
        calculations. (Bug #18711306, Bug #72548)

      * InnoDB: On mysqld start, specifying multiple data files using
        the innodb_data_file_path option would return a Space id in
        fsp header error after data is written to the second file.
        (Bug #18767811)

      * InnoDB: A DELETE operation on a table with full-text search
        indexes raised an assertion. (Bug #18683832)
        References: See also Bug #14639605.

      * InnoDB: When calling the memcached flush_all command, InnoDB
        attempts to initialize a connection and a transaction. If the
        transaction is in TRX_STATE_NOT_STARTED state, InnoDB would
        fail to set CONN_DATA->CRSR_TRX to NULL, resulting in a
        serious error. (Bug #18652854)

      * InnoDB: When InnoDB is built as a shared library, attempting
        to load the InnoDB full-text search (FTS) INFORMATION_SCHEMA
        plugin would fail with a Can't open shared library
        '' error. (Bug #18655281, Bug #70178)

      * InnoDB: A regression introduced in MySQL 5.6.5 would cause
        full-text search index tables to be created in the system
        tablespace (space 0) even though innodb_file_per_table was
        enabled. (Bug #18635485)

      * InnoDB: The InnoDB memcached plugin would call plugin_del
        without acquiring the lock_plugin mutex. This bug fix also
        addresses a race condition in ib_cursor_delete_row. (Bug

      * InnoDB: The fix for Bug#16418661 added superfluous
        buf_flush_list() logic to InnoDB startup code. (Bug #17798076,
        Bug #70899)

      * InnoDB: A race condition in fts_get_next_doc_id resulted in
        Duplicate FTS_DOC_ID and Cannot find index FTS_DOC_ID_INDEX in
        InnoDB index translation table errors. (Bug #17447086, Bug
        References: See also Bug #16469399.

      * InnoDB: Due to differences in memory ordering on different
        processor types, some mutex and read-write lock flags were not
        read consistently. (Bug #11755438, Bug #47213)

      * Partitioning: Selecting from a table having multiple columns
        in its primary key and partitioned by LIST COLUMNS(R), where R
        was the last (rightmost) column listed in the primary key
        definition, returned an incorrect result. (Bug #17909699, Bug

      * Replication: mysqlbinlog --raw did not check for errors caused
        by failed writes, which could result in silent corruption of
        binary logs. Now in such cases it stops with an error. (Bug
        #18742916, Bug #72597)

      * Replication: When a slave worker thread tried to execute a
        statement that was too large, the resulting error caused a
        crash. Now in such cases, the error is truncated to fit the
        size of the buffer. (Bug #18563480)

      * Replication: When using row-based replication, updating or
        deleting a row on the master that did not exist on the slave
        led to failure of the slave when it tried to process the
        change. This problem occurred with InnoDB tables lacking a
        primary key. (Bug #18432495, Bug #72085)

      * Replication: Quotation marks were not always handled correctly
        by LOAD DATA INFILE when written into the binary log. (Bug
        #18207212, Bug #71603)

      * Replication: Beginning in MySQL 5.6.20, when a user specified
        AUTO_INCREMENT value falls outside of the range between the
        current AUTO_INCREMENT value and the sum of the current and
        number of rows affected values it is replicated correctly. In
        previous versions, an error was generated by the slave even if
        the user specified AUTO_INCREMENT value fell outside of the
        range. (Bug #17588419, Bug #70583)

      * Replication: A group of threads involved in acquiring locks
        could deadlock when the following events occurred:

          1. Dump thread reconnects from slave; on master, a new dump
             thread tries to kill zombie dump threads; having acquired
             the thread's LOCK_thd_data, it is about to acquire

          2. Application thread executing show binary logs, having
             acquired LOCK_log and about to acquire LOCK_index.

          3. Application thread executing PURGE BINARY LOGS; having
             acquired LOCK_index, it is about to acquire

          4. Application thread executing SHOW PROCESSLIST (or SELECT

             * FROM INFORMATION_SCHEMA.PROCESSLIST), having acquired
             LOCK_thread_count and about to acquire the zombie dump
             thread's LOCK_thd_data.
        This leads to the 4 threads deadlocking in the same order
        which the threads have been listed here.
        This problem arises because there are ordering rules for
        LOCK_log and LOCK_index, as well as rules for ordering
        LOCK_thread_count and LOCK_thd_data, but there are no rules
        for ordering across these two sets of locks. This was because
        the internal mysqld_list_processes() function invoked by SHOW
        PROCESSLIST acquired LOCK_thread_count for the complete
        lifetime of the function as well as acquiring and releasing
        each thread's LOCK_thd_data. Now this function takes a copy of
        the threads from the global thread list and performs its
        traversal on these, and only after releasing
        LOCK_thread_count. During this traversal, removal from the
        global thread list is blocked using LOCK_thd_remove such that
        the copies that would otherwise be destroyed by the removal
        remain valid during traversal. The locking order following
        this fix is shown here:
LOCK_thd_remove -> LOCK_thd_data -> LOCK_log -> LOCK_index -> LOCK_th
        (Bug #17283409, Bug #69954)

      * Replication: On Windows, mysqldump failed if the error log
        file was deleted (missing) from the active MySQL server. (Bug

      * Replication: Client applications should be able to set the
        BINLOG_DUMP_NON_BLOCK flag in the initial handshake packet
        (COM_BINLOG_DUMP). Clients connecting to a server issuing a
        COM_BINLOG_DUMP with the flag unset do not get an EOF when the
        server has sent the last event in the binary log, which causes
        the connection to block. This flag, which was removed in error
        in MySQL 5.6.5, is now restored in the current release.
        As part of this fix, a new --connection-server-id option is
        added to mysqlbinlog. This option can be used by the client to
        test a MySQL server for the presence of this issue. (Bug
        #71178, Bug #18000079)

      * When a SELECT included a derived table in a join in its FROM
        list and the SELECT list included COUNT(DISTINCT), the COUNT()
        returned 1 even if the underlying result set was empty. (Bug
        References: This bug is a regression of Bug #11760197.

      * Enabling optimizer trace could cause a server exit for queries
        with a subquery in a HAVING clause. (Bug #18791851)

      * SHA and MD5 functions failed for operations using the internal
        filename character set and could cause a server exit. (Bug

      * Large arguments passed to mysqldump could lead to buffer
        overflow and program exit. (Bug #18779944)

      * Compiler flags were not passed to DTrace, causing problems for
        32-bit builds cross-compiled on 64-bit platforms. (Bug

      * ALTER TABLE on a partitioned table could result in the wrong
        storage engine being written into the table's .frm file and
        displayed in SHOW CREATE TABLE. (Bug #18618561)

      * With the max_heap_table_size system variable set to a large
        value (20GB), creation of a temporary table or a table using
        the MEMORY storage engine caused a server exit. (Bug

      * For debug builds, a 0x00 character in a full-text query string
        that used the ujis_japanese_ci, utf8mb4_turkish_ci, or
        eucjpms_bin collation could raise an assertion. (Bug

      * mysqladmin password masked the old password given on the
        command line, but not the new password. (Bug #18163964)

      * yaSSL code had an off-by-one error in certificate decoding
        that could cause buffer overflow.
        yaSSL code had an opendir() without a corresponding
        closedir(). (Bug #18178997, Bug #17201924)

      * For full-text queries on InnoDB tables, attempts to access
        deleted document IDs could lead to a server exit. (Bug

      * MyISAM temporary files could be used to mount a code-execution
        attack. (Bug #18045646)

      * For queries that selected from the Performance Schema
        events_statements_current table, adding an ORDER BY clause
        could produce incorrect results. (Bug #17729044)

      * If a query had both MIN()/MAX() and
        aggregate_function(DISTINCT) (for example, SUM(DISTINCT)) and
        was executed using Loose Index Scan, the result values of
        MIN()/MAX() were set improperly. (Bug #17217128)

      * For UNION statements, the rows-examined value was calculated
        incorrectly. This was manifest as too-large values for the
        ROWS_EXAMINED column of Performance Schema statement tables
        (such as events_statements_current). (Bug #17059925)

      * Clients could determine based on connection error message
        content whether an account existed. (Bug #16513435, Bug

      * An assertion could be raised when creating a index on a prefix
        of a TINYBLOB or GEOMETRY column in an InnoDB column. (Bug
        #16368875, Bug #18776592, Bug #17665767)

      * Use of a nonmultibyte algorithm for skipping leading spaces in
        multibyte strings could cause a server exit. (Bug #12368495,
        Bug #18315770)

      * For a view defined on a UNION, the server could create an
        invalid view definition. (Bug #65388, Bug #14117018, Bug
        #72018, Bug #18405221)

      * Configuring with cmake -DWITHOUT_SERVER to build clients
        without the server failed for builds outside of the source
        tree. (Bug #66000, Bug #14367046)

      * With big_tables enabled, queries that used COUNT(DISTINCT) on
        a simple join with a constant equality condition on a
        non-duplicate key returned incorrect results. (Bug #52582, Bug
        References: See also Bug #18853696.

      * Deadlock could occur if three threads simultaneously performed
        INSTALL PLUGIN, SHOW VARIABLES, and mysql_change_user(). (Bug
        #71236, Bug #18008907, Bug #72870, Bug #18903155)

      * mysql_config_editor exited when given an empty argument to the
        --login-path option. (Bug #71837, Bug #18311024, Bug

      * MySQL did not compile with Bison 3. A workaround is to
        downgrade to Bison 2. (Bug #71250, Bug #18017820, Bug

      * Uninstalling and reinstalling semisynchronous replication
        plugins while semisynchronous replication was active caused
        replication failures. The plugins now check whether they can
        be uninstalled and produce an error if semisynchronous
        replication is active. To uninstall the master-side plugin,
        there must be no semisynchronous slaves. To uninstall the
        slave-side plugin, there must be no semisynchronous I/O
        threads running. (Bug #70391, Bug #17638477)

      * If there was a predicate on a column referenced by MIN() or
        MAX() and that predicate was not present in all the
        disjunctions on key parts earlier in the compound index, Loose
        Index Scan returned an incorrect result. (Bug #71097, Bug

      * Client auto-reconnect did not work for clients linked against
        libmysqlclient, even with MYSQL_OPT_RECONNECT enabled. (Bug
        #70026, Bug #17309863)

      * Upgrades using RPM packages could change the ownership of an
        installation directory. (Bug #71715, Bug #18281535)

      * Proxy users were unable to execute statements if the proxied
        user password had expired. (Bug #71337, Bug #18057562)

      * A new CMake option, SUNPRO_CXX_LIBRARY, enables linking
        against libCstd instead of stlport4 on Solaris 10 or later.
        This works only for client code because the server depends on
        C++98. Example usage:
        (Bug #72352, Bug #18605389)

      * File permissions and line endings of several test and
        configuration files were made more consistent to avoid
        warnings from package checkers. (Bug #68521, Bug #16415173,
        Bug #16395459, Bug #68517, Bug #16415032, Bug #71112, Bug
        #17919313, Bug #71113, Bug #17919422)

On Behalf of the MySQL/ORACLE RE Team,

Akhil Mohan

MySQL Community Server 5.6.20 has been releasedkaren langford1 Aug