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From:Hery Ramilison Date:October 16 2017 1:20pm
Subject:MySQL Community Server 5.7.20 has been released
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Dear MySQL users,

MySQL Server 5.7.20, a new version of the popular Open Source
Database Management System, has been released. MySQL 5.7.20 is
recommended for use on production systems.

For an overview of what's new in MySQL 5.7, please see

For information on installing MySQL 5.7.20 on new servers, please see
the MySQL installation documentation at

MySQL Server 5.7.20 is available in source and binary form for a number of
platforms from our download pages at

MySQL Server 5.7.20 is also available from our repository for Linux
platforms, go here for details:

Windows packages are available via the Installer for Windows or .ZIP
(no-install) packages for more advanced needs. The point and click
configuration wizards and all MySQL products are available in the
unified Installer for Windows:

5.7.20 also comes with a web installer as an alternative to the full

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.

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

The following link lists the changes in the MySQL 5.7 since the
the release of MySQL 5.7.19.


Changes in MySQL 5.7.20 (2017-10-16)
    Audit Log Notes

      * Event-matching filter rules for the audit_log plugin now
        support an abort element, which can be used to prevent
        qualifying events from executing. For more information,
        see Audit Log Filtering
        This capability can be used, for example, to
        augment the capabilities of MySQL Enterprise Firewall,
        which blocks SQL statements on a per-user basis, by
        writing audit filtering rules that match statements and
        block them based on characteristics of the statements

    Deprecation and Removal Notes

      * Previously, the --transaction-isolation and
        --transaction-read-only server startup options
        corresponded to the tx_isolation and tx_read_only system
        variables. For better name correspondence between startup
        option and system variable names, transaction_isolation
        and transaction_read_only have been created as aliases
        for tx_isolation and tx_read_only. The tx_isolation and
        tx_read_only variables are now deprecated and will be
        removed in MySQL 8.0. Applications should be adjusted to
        use transaction_isolation and transaction_read_only

      * The query cache is now deprecated and is removed in MySQL
        8.0. Deprecation includes these items:


           + The SQL_CACHE and SQL_NO_CACHE SELECT modifiers.

           + These system variables: have_query_cache,
             ndb_cache_check_time, query_cache_limit,
             query_cache_min_res_unit, query_cache_size,
             query_cache_type, query_cache_wlock_invalidate.

           + These status variables: Qcache_free_blocks,
             Qcache_free_memory, Qcache_hits, Qcache_inserts,
             Qcache_lowmem_prunes, Qcache_not_cached,
             Qcache_queries_in_cache, Qcache_total_blocks.

      * The mysql client by default strips comments in statements
        sent to the server, and this behavior is controlled using
        --skip-comments (strip comments), and --comments
        (preserve comments).
        Comment stripping is now deprecated. This feature and the
        options to control it will be removed in a future MySQL

      * These syntax constructs for table and column references
        are now deprecated and will be removed in a future
        version of MySQL. Instances of these constructs should be
        changed to remove the leading period.

           + .col_name

           + .tbl_name

           + .tbl_name.col_name

    Installation Notes

      * For platforms that use systemd (see Managing MySQL Server
        with systemd
        the data directory is initialized if empty at server
        startup. This might be a problem if the data directory is
        a remote mount that has temporarily disappeared: The
        mount point would appear to be an empty data directory,
        which then would be initialized as a new data directory.
        It is now possible to suppress this automatic
        initialization behavior. specify the following line in
        the /etc/sysconfig/mysql file (create the file if it does
        not exist):
        (Bug #26595288, Bug #87287)

    Packaging Notes

      * mysqlcheck was missing in the MySQL Server Docker image,
        which prevented mysql_upgrade from running. (Bug
        #26400146, Bug #86968)

    Security Notes

      * Certificates automatically generated by mysqld and
        mysql_ssl_rsa_setup now use X509 v3 rather than v1. (Bug

      * The keyring_okv plugin now supports password-protecting
        the key file used for secure connections. See Using the
        keyring_okv KMIP Plugin

    X Plugin Notes

      * A Mysqlx.Connection.CapabilitiesGet request using MySQL X
        Protocol did not return the complete list of available
        authentication mechanisms. (Bug #26044113)

      * For mixed case or uppercase schema names, the statement
        list_objects could incorrectly report a collection as a
        table. (Bug #25769683)

      * The X Plugin was omitted from the list of plugins to
        include for testing data directory permissions. (Bug

    Functionality Added or Changed

      * Replication: In previous versions issuing STOP
        GROUP_REPLICATION stopped the plugin but the server still
        accepted transactions. This meant the transactions were
        not transmitted to the group. To make STOP
        GROUP_REPLICATION safer, now super_read_only is set to ON
        immediately upon issuing STOP GROUP_REPLICATION, which
        ensures no transactions are accepted. (Bug #25495067, Bug

      * Replication: The group_replication_member_weight variable
        has been added which enables you to control the election
        of new primaries in single-primary mode. In previous
        versions primary election was based on the member's UUID,
        with the lowest UUID elected as the new primary in the
        event of fail over. Use this variable to assign numeric
        weights to members to ensure that specific members are
        elected, for example during scheduled maintenance of the
        primary or to ensure certain hardware is prioritised.

    Bugs Fixed

      * InnoDB: Invalid error handling code was removed from a
        function related to tablespace import. (Bug #26595476)

      * InnoDB: A check for discarded partitions during a DML
        operation only checked the first partition. Failure to
        check for other discarded partitions caused an assertion
        failure. (Bug #25942592)

      * InnoDB: Replication lag occurred on slave instances
        during large update operations on tables with many
        partitions. (Bug #25687813, Bug #85352)

      * InnoDB: A failure occurred during an end range
        comparison. (Bug #25669686)

      * InnoDB: Enabling the innodb_buffer_pool_load_now setting
        failed in readonly mode. The event that signals the
        buffer pool load thread was not initialized. (Bug

      * InnoDB: Test-related code intended to simulate a random
        read on a non-existent page raised an invalid assertion.
        (Bug #25479538)
        References: This issue is a regression of: Bug #25053705.

      * InnoDB: A long wait for a dictionary operation lock held
        by a full-text search synchronization operation caused a
        server exit. (Bug #24938374)

      * Partitioning: In certain cases when fetching heap records
        a partition ID could be set to zero. (Bug #86255, Bug

      * Partitioning: Queries involving NULL were not always
        handled correctly on tables that were partitioned by
        LIST. (Bug #76418, Bug #20748521)
        References: See also: Bug #86255, Bug #26034430.

      * Replication: MySQL internal administration commands that
        update replication-specific repository tables, for
        example during a replication synchronization check using
        the mysqlrplsync utility, can now bypass read locks. This
        enables such commands to execute regardless of the
        settings for the read_only and super_read_only system
        variables and the autocommit mode. (Bug #26414532, Bug

      * Replication: When the Group Replication plugin
        Delayed_initialization_thread failed to start due to
        unavailable resources, a locked mutex was being kept
        behind which would cause issues on
        Delayed_initialization_thread destructor. The fix ensures
        that the mutex is unlocked when the thread fails to
        start. (Bug #26394678)

      * Replication: If hostname resolution was not working for a
        member in Group Replication, the error returned when
        attempting to connect was referring to credentials. The
        error message has been improved to describe the problem
        with hostname resolution. (Bug #26368004)

      * Replication: If the options file contained Group
        Replication related settings the server could stop
        unexpectedly on start up. (Bug #26314472)

      * Replication: FLUSH LOGS attempted to send an OK message
        after having already sent an error response during the
        commit phase. (Bug #26272158)

      * Replication: With some workloads that contained large
        inserts, the XCOM transaction cache could consume a large
        amount of memory. The fix limits the size of the cache to
        reduce the impact to memory usage. (Bug #26241291)

      * Replication: Group Replication partition threads were not
        visible in the Performance Schema tables. (Bug #26241008)

        was set to an incorrect value when
        ified" on a recovering member. (Bug #26180350)

      * Replication: The values of the
        group_replication_recovery_use_ssl and
        variables were not being updated when configured for the
        Group Replication recovery channel. (Bug #26142801)

      * Replication: When replicating a partitioned table with an
        index, on a replication slave where HASH_SCAN was
        specified as part of the slave_rows_search_algorithms
        setting, the slave I/O thread sometimes stopped with an
        error HA_ERR_KEY_NOT_FOUND. (Bug #26137159)

      * Replication: group_replication_force_members could be
        used in situations where the group was working properly,
        in other words a majority was reachable. This incorrect
        use could cause instability in the group. Therefore, its
        use has been restricted to the scenario for which it was
        created, for forming a new membership from a subset of a
        previous group's membership when a majority of the
        members are unreachable. (Bug #26093967)

      * Replication: The delayed initialization mechanism used
        for server starts has been improved. Now, it only blocks
        connections until the server is in read mode. (Bug
        References: See also: Bug #84731, Bug #25475132.

      * Replication: It was possible to set server_uuid to the
        same value as group_replication_group_name. Doing so
        could result in unexpected behavior because GTIDs are
        identified by a UUID. Now it is not possible to set
        server_uuid to the same value as
        group_replication_group_name. (Bug #26035931)

      * Replication: The system variable pseudo_slave_mode, which
        is for internal server use, sometimes raised an assertion
        when it was changed inside a transaction. The server no
        longer changes this variable inside a transaction. (Bug
        #26034192, Bug #86250)

      * Replication: When a primary member, for example the
        primary in single-primary group or in a multi-primary
        group, which also had asynchronous replication channels
        feeding data into it was stopped, the asynchronous
        channels would continue applying changes. Although
        super_read_only was being set when STOP GROUP_REPLICATION
        was issued, this did not stop any running asynchronous
        replication channels which were already running. This
        meant that changes could be made locally on the member,
        and that the asynchronous replication channels had to be
        stopped manually. Now when Group Replication stops,
        either due to an error or when STOP GROUP_REPLICATION is
        issued, all asynchronous replication channels are
        stopped. (Bug #26024253)

      * Replication: When write sets are used for parallelization
        by a replication slave (as specified by the
        binlog_transaction_dependency_tracking system variable),
        empty transactions are now ignored, and the handling of
        relay log rotation has been optimized. (Bug #25982097)

      * Replication: A misleading warning was issued when the
        command FLUSH LOGS or PURGE LOGS BEFORE was used on a
        binary log file with an expiry time set, and the binary
        log file was in use. The warning related to the file
        being in use, and implied that a purge attempt had taken
        place, even if the expiry time had not yet been reached.
        Now, MySQL checks the expiry time of the binary log file
        first, and only then checks whether the file is in use.
        So the warning is only issued for an in-use binary log
        file that is old enough to be purged. (Bug #25973525)

      * Replication: Group Replication stopped unexpectedly when
        more than 1024 file descriptors were in use. (Bug

      * Replication: Now that XA transactions are prepared and
        committed in two parts, an issue with statement-based
        replication has been identified. If two XA transactions
        committed on the master are being prepared on the slave
        in the inverse order, locking dependencies can occur that
        cannot be safely resolved. The issue is not present with
        row-based replication.
        XA transactions are therefore now considered unsafe for
        statement-based replication.

           + When binlog_format = STATEMENT, a warning is issued
             for DML statements inside XA transactions, and
             replication might fail with deadlock on slaves.

           + When binlog_format = MIXED, DML statements inside XA
             transactions are logged using row-based replication.

           + When binlog_format = ROW, DML statements inside XA
             transactions are logged as before.
        (Bug #25786490, Bug #85639)

      * Replication: If the Group Replication plugin was
        uninstalled while a group was running, the plugin was
        marked for uninstall. This could cause the server
        shutdown to not complete successfully. The fix ensures
        that the Group Replication plugin cannot be uninstalled
        if the majority of the group cannot be reached. In such a
        case it is necessary to issue STOP GROUP_REPLICATION
        before uninstalling the plugin. (Bug #25673788)

      * Replication: Replication clients no longer enable LOCAL
        capability for LOAD DATA statements, because they do not
        use LOAD DATA LOCAL statements. (Bug #24763131)

      * Replication: In case of a failure while creating multiple
        slave applier worker threads, some threads would be left
        orphaned and their resources would not be collected.
        Thanks to Laurynas Biveinis for his contribution to
        fixing this bug. (Bug #24679056, Bug #82980)

      * Replication: The binlog_checksum option cannot be changed
        within a transaction. MySQL cannot log this statement, as
        would be required inside a transaction, while the
        requested function is being performed on the binary log.
        (Bug #22914463)

      * Replication: The logging of Group Replication has been
        improved. Now logging includes information when a member
        joins or leaves, when the view changes, and so on. (Bug
        #84798, Bug #25495393)

      * Compiling with -DWITHOUT_SERVER=1 resulted in
        my_symlink.c compilation failure due to missing #include
        for my_dir.h. Thanks to Christian Hesse for the patch.
        (Bug #26495816, Bug #87137)

      * yaSSL could incorrectly perform TLS cipher negotiation.
        (Bug #26482173)

      * The Linux RPM spec file for RHEL6 and higher is updated
        with comments that recommend installing the
        redhat-rpm-config package to add convenience macros that
        make rebuilding the RPM package easier. Thanks to Simon
        Mudd for the patch. (Bug #26474153, Bug #87098)

      * If the error log was misconfigured and the server could
        not start, no output indicating the problem was produced.
        (Bug #26447825, Bug #87087)

      * mysqld_multi was modified to use mysqld --initialize
        rather than the deprecated mysql_install_db. Thanks to
        Zhan Shi for the patch. (Bug #26446321, Bug #87080)

      * Adding an ORDER BY to a query that included an outer join
        and a subquery caused a constant value defined for a
        column in the subquery to be incorrectly promoted to a
        constant value in the case when the subquery returns 0
        rows. (Bug #26432173)

      * The server failed to check the maximum path length for
        partition names. (Bug #26390632)

      * Identifiers containing a mixture of backslashes and
        backticks could be parsed incorrectly. (Bug #26372491)

      * Source packages for Debian platforms contained prebuilt
        debug binaries, causing build failures on any
        architectures other than the one on which those binaries
        were built. (Bug #26186911)

      * The mysqld_pre_systemd script in RPM packages found the
        error log setting in option files if specified as
        log-error but not as log_error, though both are
        permitted. (Bug #26148391, Bug #86466)

      * When running mysqlbinlog with the
        --read-from-remote-server option, rewrite rules specified
        using the --rewrite-db option were ignored, so data was
        not written to the target database. (Bug #26117735, Bug

      * REFERENCES privilege checking could use the incorrect
        database in some cases. (Bug #26106655)

      * Uninstalling the daemon_memcached plugin caused a serious
        error. (Bug #25909540)

      * The test case file did not find the data
        difference between servers. Thanks to Yura Sorokin for
        the patch. (Bug #25860138, Bug #85838)

      * An ngram fulltext parser search query returned incorrect
        results and raised an assertion. (Bug #25851975)

      * Selecting from a view could yield different results with
        materialization enabled versus materialization disabled.
        (Bug #25782811, Bug #85622)

      * The Performance Schema failed to check the maximum host
        length for client connections. (Bug #25510805)

      * mysqlpump displayed incorrect progress information about
        the number of tables dumped. (Bug #25432850)

      * Some mysqldump warnings went to the standard output
        rather than the standard error output and consequently
        were written to the dump file. (Bug #25380000, Bug

      * LOAD DATA failed to accept multibyte characters that
        followed an escape sequence. (Bug #25147988, Bug #83950,
        Bug #25865525)

      * A server error occurred when a full text search result
        exceeded the innodb_ft_result_cache_limit setting. The
        patch for this bug also backports a related patch (Bug
        #21140111). (Bug #25033538)

      * If a stored function was considered a constant by the
        optimizer, calling it from a subquery in a NOT IN
        condition in the WHERE clause could cause a server exit.
        (Bug #23577867)

      * A mysqldump memory leak was fixed. Thanks to Yura Sorokin
        for the patch. (Bug #23531150, Bug #81714)

      * Incorrect results or a server exit could result when a
        query used Batched Key Access optimization and a virtual
        generated column was part of the join buffer. (Bug

      * If a session rolled back to a savepoint and then was
        killed, the statements up to the point of the savepoint
        could be committed. (Bug #22350047, Bug #79596)

      * For clients that used Connector/Python and authenticated
        using the sha256_password plugin, the server could handle
        connections incorrectly. (Bug #21421642)

On Behalf of the MySQL/Oracle Release Engineering Team,
Hery Ramilison
MySQL Community Server 5.7.20 has been releasedHery Ramilison16 Oct