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From:Balasubramanian Kandasamy Date:August 3 2015 3:03pm
Subject:MySQL Community Server 5.7.8 has been released (part 2/3)
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[This is part 2 of the announcement ]

      * InnoDB: A cascade operation resulted in a duplicate entry
        error in FTS_DOC_ID_INDEX. The same document ID was used
        by two cascade operations. (Bug #21111301, Bug #77087)

      * InnoDB: Starting the server with an invalid
        innodb_data_file_path setting did not produce a
        sufficiently informative error message. (Bug #21103446,
        Bug #77056)

      * InnoDB: A regression introduced in MySQL 5.7.5 caused
        sorting to be skipped when rebuilding a table after
        dropping a single-column primary key. (Bug #21103101)

      * InnoDB: Opening a foreign key-referenced table with
        foreign_key_checks enabled resulted in an error when the
        table or database name contained special characters. (Bug
        #21094069)

      * InnoDB: The page_zip_verify_checksum function returned
        false for a valid compressed page. (Bug #21086723)

      * InnoDB: DDL operations for tablespaces could fail to
        implicitly commit the current transaction. (Bug
        #21081898)

      * InnoDB: The rollback of a partially completed transaction
        containing more than one update to a spatial index raised
        an assertion in row_ins_sec_index_entry_by_modify(). (Bug
        #21076238)

      * InnoDB: In the case of a lock conflict, shutdown could
        hang waiting for asynchronous rollback to finish. (Bug
        #21075892)

      * InnoDB: To avoid conflicts with implicitly created
        file-per-table tablespaces, CREATE TABLESPACE ... ADD
        DATAFILE no longer supports creation of tablespace data
        files in subdirectories under the MySQL data directory
        (datadir). Additionally, the data file path specified in
        a CREATE TABLESPACE ... ADD DATAFILE statement must be an
        existing directory. InnoDB no longer creates missing
        directories for CREATE TABLESPACE ... ADD DATAFILE
        statements. (Bug #21068487)

      * InnoDB: SHOW ENGINE INNODB MUTEX functionality, which was
        removed in MySQL 5.7.2, was revised and added back. Mutex
        statistics collection can now be configured dynamically
        using the following options:

           + To enable the collection of mutex statistics, run:
             SET GLOBAL innodb_monitor_enable='latch';

           + To reset mutex statistics, run:
             SET GLOBAL innodb_monitor_reset='latch';

           + To disable the collection of mutex statistics, run:
             SET GLOBAL innodb_monitor_disable='latch';
        For more information, see SHOW ENGINE Syntax
        (http://dev.mysql.com/doc/refman/5.7/en/show-engine.html)

        Sync debug checking for the InnoDB storage engine,
        previously defined under UNIV_SYNC_DEBUG, is now defined
        under UNIV_DEBUG and is available when debugging support
        is compiled in using the WITH_DEBUG CMake option. When
        debugging support is compiled in, InnoDB sync debug
        checking is controlled by the innodb_sync_debug
        configuration option. (Bug #21052754)

      * InnoDB: A tablespace opened locally by a truncate routine
        was not closed in protected mode. (Bug #21046968)

      * InnoDB: An assertion was raised when truncation logic
        identified inactive undo tablespaces as candidates for
        undo log truncation. Some undo tablespaces were left
        inactive when the number of available undo tablespaces
        exceeded the number of undo logs. (Bug #21046781)

      * InnoDB: At startup, InnoDB updated the SYS_DATAFILES
        internal system table with the space_id and path of each
        system tablespace file even though a record was already
        present and SYS_DATAFILES.PATH matched the current value.
        (Bug #21044191)

      * InnoDB: In Windows debug builds, an innodb_flush_method
        setting of normal or unbuffered raised an assertion. (Bug
        #20981684)

      * InnoDB: Transactions could be subjected to rollback while
        performing DDL operations. The transactions were not
        marked as DDL transactions, and
        TRX_FORCE_ROLLBACK_DISABLE was not set. (Bug #20979020)

      * InnoDB: An ALTER TABLE ... IMPORT TABLESPACE operation on
        a table with prefix index failed with a schema mismatch
        error. (Bug #20977779, Bug #76877)

      * InnoDB: Initializing the database with an
        innodb_page_size setting of 64K and a system tablespace
        data file size less than 12MB raised an assertion. With
        an InnoDB page size of 64KB, the first system tablespace
        data file (ibdata1) was not large enough to contain the
        doublewrite buffer blocks (block1 and block2). To ensure
        that the doubwrite buffer blocks fit within the first
        system tablespace data file, a minimum data file size is
        now enforced. If innodb_page_size is less than or equal
        to 16KB, the minimum data file size for the first system
        tablespace data file (ibdata1) is 3MB. For
        innodb_page_size=32k, the minimum data file size is 6MB.
        For innodb_page_size=64k, the minimum data file size is
        12MB. (Bug #20972309)

      * InnoDB: Full-text search operations between tables
        related by a foreign key constraint were not properly
        cascaded during iterative DML cascading operations. (Bug
        #20953265)

      * InnoDB: In MySQL 5.7.2, 32 of 128 undo logs (rollback
        segments) were reserved as non-redo undo logs for
        temporary table transactions. With one of the remaining
        undo logs always allocated to the system tablespace, 95
        undo logs remained available for allocation to the system
        tablespace or separate undo tablespaces. This change
        effectively reduced the innodb_undo_tablespaces maximum
        limit from 126 to 95. In other words, a limit of 95
        available undo logs also limited the maximum number of
        undo tablespaces to 95. In MySQL 5.7.8, the
        innodb_undo_tablespaces maximum value is officially
        reduced to 95. (Bug #20938115)

      * InnoDB: A memory leak occurred when a foreign key
        constraint object was loaded with the parent table while
        the child table failed to load. The foreign key
        constraint object should only be loaded with the child
        table. (Bug #20926253, Bug #21041449)

      * InnoDB: Debug only code set m_prebuilt, which may affect
        in-place ALTER TABLE behaviour. m_prebuilt to should not
        be used to store an intermediate value in debug-only
        code. (Bug #20921940)

      * InnoDB: The definition of the fil_node_t data structure
        was moved from fil0fil.cc to fil0fil.h so that diagnostic
        code outside that module can access information about
        files that belong to a tablespace. (Bug #20886222)

      * InnoDB: Assertion code was revised to avoid compiler
        warnings that occurred when compiling MySQL on Mac OS X
        10.10.2. (Bug #20883256)

      * InnoDB: After upgrading to MySQL 5.7.6 or later,
        restarting the server after truncating a table that was
        originally created in MySQL 5.7.5 or earlier raised an
        "incorrect MERGE_THRESHOLD length in SYS_INDEXES" error.
        A MERGE_THRESHOLD column was added to the internal
        SYS_INDEXES table in MySQL 5.7.6. SYS_INDEXES records for
        tables that were not rebuilt or imported after upgrading
        did not include the new column. The TRUNCATE TABLE
        operation updated the table's SYS_INDEXES records to
        include the new column but set the MERGE_THRESHOLD value
        to NULL. (Bug #20882432)

      * InnoDB: A failure to load a change buffer bitmap page
        during a concurrent delete tablespace operation caused a
        server exit. (Bug #20878735)

      * InnoDB: A shutdown hang occurred when an
        innodb_force_recovery setting of 3 or higher prevented
        the rollback of transactions that were in an ACTIVE
        state. ACTIVE transactions are now placed in XA PREPARE
        state in the main-memory data structure to allow shutdown
        to proceed normally. The transactions are recovered as
        ACTIVE on the next restart and are rolled back unless
        innodb_force_recovery is again set to 3 or higher. (Bug
        #20874411)

      * InnoDB: If a server exit occurred during an XA ROLLBACK,
        the transaction was incorrectly recovered in XA PREPARE
        state. As a result, subsequent XA COMMIT transactions
        were possible, which would break ACID compliance and
        potentially cause corruption between indexes of a table.
        (Bug #20872655)

      * InnoDB: A CREATE TABLESPACE operation raised a Valgrind
        error due to a memory leak in the
        os_create_subdirs_if_needed function. (Bug #20865674)

      * InnoDB: Calls to buf_page_print() were removed to avoid
        filling mysql-test-run logs with InnoDB page dumps. Page
        dumps related to file I/O are still printed. (Bug
        #20863042)

      * InnoDB: CREATE TABLESPACE failed to move internal
        tablespace files to a reserved name space that starts
        with an innodb_ prefix, permitting internal tablespace
        files to be dropped. (Bug #20840368)

      * InnoDB: A TRUNCATE TABLE operation on a general
        tablespace table with a full-text search index raised an
        assertion. (Bug #20834483)

      * InnoDB: An assertion was raised on shutdown due to XA
        PREPARE transactions holding explicit locks. (Bug
        #20816223)

      * InnoDB: The fts_print_doc_id function printed too much
        debug information in debug builds. fts_enable_diag_print
        is now used instead. (Bug #20811125)

      * InnoDB: After a failed DROP TABLE operation, the purge
        background thread asserted while attempting to access an
        index page of the table. Purge should not attempt to
        clean a table that is marked as corrupt. Purge now checks
        for a corrupt primary index. (Bug #20789078, Bug #75913)

      * InnoDB: A checksum mismatch error on a crc32 checksum was
        encountered when restarting the server on a data file
        copied from a machine with a different endianness. The
        crc32 checksum should be recognized regardless of the
        native byte order of the system where the checksum was
        generated. (Bug #20783098, Bug #76375)

      * InnoDB: An ALTER TABLE ... DROP INDEX operation on a
        table with foreign key dependencies raised an assertion.
        (Bug #20768847)

      * InnoDB: An assertion was raised when InnoDB attempted to
        dereference a NULL foreign key object. (Bug #20762798)

      * InnoDB: An ALTER TABLE operation raised an assertion due
        a regression introduced in MySQL 5.7.6 with the
        introduction of native partitioning support for general
        tablespaces. (Bug #20759613)

      * InnoDB: In some instances, functions that call DBUG_ENTER
        did not call DBUG_RETURN. (Bug #20753620, Bug #76447)

      * InnoDB: A regression of the trx_is_started function in
        MySQL 5.7.6 caused a shutdown hang. (Bug #20744155)

      * InnoDB: The MeCab full-text plugin parser failed to
        handle an out-of-memory exception. (Bug #20742590)

      * InnoDB: An assertion was raised during a rollback
        operation due to a record the was incorrectly
        undelete-marked. (Bug #20734998)

      * InnoDB: An assertion was raised in a debug build when an
        ALTER TABLE operation invoked obsolete foreign key code
        while attempting to create an intrinsic temporary table
        as part of an optimizer plan. Temporary tables do not
        support foreign keys. Invocation of foreign key code is
        now blocked for intrinsic temporary tables. (Bug
        #20730289)

      * InnoDB: An INSERT operation raised an assertion. The
        calculation that determines the number of extents to
        reserve when storing a BLOB did account for compressed
        pages. (Bug #20713559)

      * InnoDB: Missing brackets in the fsp_flags_is_valid
        function could result in a failure to recognize a
        corrupted data file. (Bug #20671465)

      * InnoDB: A query that used a percentage character '%' as
        the last character in a query token raised a full-text
        parser plugin assertion. Full-text parser plugins created
        using the full-text parser plugin framework now ignore
        the '%' character if specified as the first or last
        character in a query token. Using the '%' character as
        the first character in a query token is not permitted by
        the internal SQL parser. Using the '%' character as last
        character in a query token is reserved for prefix
        matching. (Bug #20668156)

      * InnoDB: The INFORMATION_SCHEMA.FILES table now reports
        metadata for all InnoDB tablespace types including
        file-per-table tablespaces, general tablespaces, the
        system tablespace, temporary table tablespaces, and undo
        tablespaces (if present). System tablespace and temporary
        table tablespace metadata is no longer reported by the
        INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES and
        INFORMATION_SCHEMA.INNODB_SYS_DATAFILES tables. However,
        these tables continue to provide metadata for
        file-per-table and general tablespaces. (Bug #20660744,
        Bug #21086257, Bug #76182)

      * InnoDB: The InnoDB full-text search feature with the
        mecab parser plugin would print an empty error message.
        (Bug #20651493, Bug #76164)

      * InnoDB: Importing a tablespace with a full-text index
        resulted in an assertion when attempting to rebuild the
        index. (Bug #20637494)

      * InnoDB: A DML operation raised an assertion in
        btr_estimate_n_rows_in_range(). The assertion code was
        too strict. (Bug #20618309)

      * InnoDB: Defining a user-created FTS_DOC_ID column as a
        primary key produced incorrect full-text search relevancy
        rankings. (Bug #20597981)

      * InnoDB: During a table import operation, an INSERT failed
        with a duplicate key error on an AUTO_INCREMENT column
        due to an incorrectly initialized AUTO_INCREMENT value.
        (Bug #20597821, Bug #76037)

      * InnoDB: After dropping a full-text search index, the
        hidden FTS_DOC_ID and FTS_DOC_ID_INDEX columns prevented
        online DDL operations. (Bug #20590013, Bug #76012)

      * InnoDB: An assertion was raised on server startup when
        InnoDB tried to create a temporary file in a non-existent
        temporary directory (tmpdir) while in read-only mode.
        (Bug #20578834)

      * InnoDB: The strict_* forms of innodb_checksum_algorithm
        settings (strict_none, strict_innodb, and strict_crc32)
        caused the server to halt when a non-matching checksum
        was encountered, even though the non-matching checksum
        was valid. For example, with
        innodb_checksum_algorithm=strict_crc32, encountering a
        valid innodb checksum caused the server to halt. Instead
        of halting the server, a message is now printed to the
        error log and the page is accepted as valid if it matches
        an innodb, crc32 or none checksum. (Bug #20568464)

      * InnoDB: After moving the MySQL data directory and
        modifying the datadir configuration parameter to point to
        the new location, tables stored in general tablespaces
        failed to open because the tablespace data file could not
        be found. To address this problem, CREATE TABLESPACE ...
        ADD DATAFILE now creates an isl file in the MySQL data
        directory when a general tablespace data file is created
        outside of the MySQL data directory. Also, the
        fil_ibd_open function now searches for general
        tablespaces in the same way that it searches for
        file-per-table tablespaces. (Bug #20563954)

      * InnoDB: General tablespaces created on Windows using a
        relative data file path could not be opened on Unix-like
        systems. InnoDB failed to convert the backslash ("\")
        directory separator that is used in the Windows version
        of the relative data file path. (Bug #20555168)

      * InnoDB: General tablespaces now support partitioned
        InnoDB tables, and individual partitions and
        subpartitions can now be assigned to a general
        tablespace. SHOW CREATE TABLE output was revised to
        include quotes around the tablespace identifier. (Bug
        #20554858, Bug #20588947)

      * InnoDB: An ALTER TABLE operation that added a spatial
        index caused the server to exit. (Bug #20547644)

      * InnoDB: Assertion code which checks for the lowest
        possible page number for a tablespace did not account for
        general tablespaces. (Bug #20544581, Bug #20810627)

      * InnoDB: The InnoDB memcached plugin handled unsigned NOT
        NULL integer columns incorrectly. Thanks to Piotr
        Jurkiewicz for the patch. (Bug #20535517, Bug #75864)

      * InnoDB: The following changes were implemented for
        full-text index auxiliary tables:

           + If the primary table is assigned to a general
             tablespace, full-text auxiliary tables are created
             in the same general tablespace.

           + Full-text auxiliary tables are created with the same
             row format as the primary table.

           + If the primary table was created in a location
             outside of the data directory using the DATA
             DIRECTORY clause, full-text auxiliary tables are
             created in the same location as the primary table.
        (Bug #20527217, Bug #75869)

      * InnoDB: The memcached set command permitted a negative
        expire time value. Expire time is stored internally as an
        unsigned integer. A negative value would be converted to
        a large number and accepted. The maximum expire time
        value is now restricted to INT_MAX32 to prevent negative
        expire time values. (Bug #20478242, Bug #75790)

      * InnoDB: An interrupted ALTER TABLE operation that
        rendered a child table unavailable caused an error and
        debug assertion after crash recovery, when the ALTER
        TABLE operation on the parent table detected that the
        foreign keys of the parent table could not be loaded. The
        debug assertion was removed and the error was replaced by
        a warning. (Bug #20476395)
        References: This bug is a regression of Bug #19267051.

      * InnoDB: In debug builds, enabling the
        btr_cur_limit_optimistic_insert_debug flag raised a
        deadlock exception in the change buffer clustered index.
        (Bug #20459905, Bug #75736)

      * InnoDB: A warning message is now printed if DB_TRX_ID
        stored in a record is found to be greater than
        max_trx_id. In debug builds, an assertion is raised. (Bug
        #20445525)

      * InnoDB: Estimates for the number of records in a range
        for a given dataset could differ depending on the page
        size. (Bug #20427694)

      * InnoDB: During shutdown on Windows, the listener object
        in handle_shutdown() was freed while the listener was
        running, resulting in an exception in
        buf_pool_from_bpage(). (Bug #20421223)

      * InnoDB: SHOW ENGINE INNODB STATUS output showed negative
        reservation and signal count values due to a counter
        overflow error. (Bug #20417397)

      * InnoDB: Failure to check the status of a cursor
        transaction read-only option before reusing the cursor
        transaction for a write operation resulted in a server
        exit during a memcached workload. (Bug #20391552)

      * InnoDB: An assertion was raised in a debug build when
        populating a spatial index during an ALTER TABLE
        operation. The size of data tuples for compressed rows is
        calculated in the rec_get_converted_size_comp_prefix_low
        function. Debug code within the function did not account
        for the spatial index or the DATA_SYS_CHILD data type in
        the node pointers. (Bug #20372749)

      * InnoDB: CHECK TABLE returned a "wrong count" error for
        tables with spatial indexes. (Bug #20313067)

      * InnoDB: MDL locks taken by memcached clients caused a
        MySQL Enterprise Backup FLUSH TABLES WITH READ LOCK
        operation to hang. (Bug #20275612)

      * InnoDB: An embedded MySQL server failed to start with
        innodb_undo_tablespaces=2. The server was unable to
        locate undo tablespaces that were created when the MySQL
        instance was initialized. For embedded MySQL
        installations, the innodb_undo_directory default value of
        "." may not be the same directory as the MySQL data
        directory. To address this problem, innodb_undo_directory
        is now NULL by default, requiring that a path be
        specified. If a path is not specified, undo tablespaces
        are created in the MySQL data directory, as defined by
        datadir. A workaround for pre-MySQL 5.7.8 embedded
        installations is to define an absolute path for
        innodb_undo_directory. (Bug #20023425)

      * InnoDB: A DML operation raised an assertion in file
        lock0lock.cc. A session holding an exclusive row lock on
        a clustered index page initiated a page reorganization
        while another session waited for a lock on the same row.
        The page reorganization changed the lock order, causing
        an assertion in lock_rec_add_to_queue(). (Bug #20005279)

      * InnoDB: A DROP DATABASE operation raised an assertion.
        (Bug #19929435)

      * InnoDB: InnoDB failed to open a tablespace after the data
        directory location of the tablespace was changed from a
        relative path to a full path. InnoDB failed to recognize
        that the relative path, which remained embedded in the
        data dictionary, pointed to the same data file as the
        full path. (Bug #19896685)

      * InnoDB: A TRUNCATE TABLE operation appeared to hang when
        run in parallel with a read-write workload. (Bug
        #19873470, Bug #74312)

      * InnoDB: The sorted index build feature introduced in
        MySQL 5.7.5 caused a performance regression when adding
        an index to a small table. The regression was due to
        excessive flushing triggered by a forced checkpoint that
        occurs after the sorted index build. (Bug #19865673, Bug
        #74472)

      * InnoDB: Updates to indexed columns could be slower in
        MySQL 5.7.5 and higher. In pre-MySQL 5.7.5 releases,
        InnoDB reserves 1/16 of the space in clustered index
        pages for future inserts and updates. This behaviour
        changed in MySQL 5.7.5 with the introduction of the
        innodb_fill_factor option. With innodb_fill_factor=100,
        B-tree index pages were completely filled during sorted
        index builds, and subsequent updates to index pages
        resulted in page splitting. To restore pre-MySQL 5.7.5
        behavior, the default setting of innodb_fill_factor=100
        now leaves 1/16 of the space in clustered index pages
        free for future index growth. (Bug #19821087, Bug #74325)

      * InnoDB: The ha_innobase::index_flags function returned
        invalid flags for spatial indexes. (Bug #19473391)

      * InnoDB: On Windows, asynchronous I/O requests remained
        waiting after InnoDB initialization was aborted. (Bug
        #19363615)

      * InnoDB: An index record was not found on rollback due to
        inconsistencies in the purge_node_t structure. (Bug
        #19138298, Bug #70214, Bug #21126772, Bug #21065746)

      * InnoDB: The ut_when_dtor struct, added in MySQL 5.7 to
        address a Valgrind issue, was removed to reduce code
        complexity. (Bug #18309926)

      * InnoDB: An INSERT operation raised an assertion when the
        transaction mode was modified after the transaction
        started. (Bug #15866285)

      * InnoDB: Queries that use both UNION and UNION ALL and
        disable the index would cause an assertion due to
        duplicate B-tree values. (Bug #76439, Bug #20752543)

      * InnoDB: In debug builds, attempting to create a spatial
        index after dropping the mysql.innodb_table_stats table
        raised an assertion in the btr_cur_open_at_rnd_pos_func
        function. (Bug #76437, Bug #20753642)

      * InnoDB: Transaction objects were passed to intrinsic
        table APIs, causing an assertion. Intrinsic tables, which
        do not support rollback and are not shared across
        connections, should ignore the transaction objects. (Bug
        #76415, Bug #20748479)

      * InnoDB: When innodb_thread_concurrency=1, queries on
        intrinsic temporary tables caused other sessions to hang.
        Queries on intrinsic temporary tables should not
        increment the number of active threads. (Bug #76346, Bug
        #20762059)

      * Partitioning: During execution of correlated subqueries,
        the server reinitialized a scan executed on the same
        table without ending the previous scan. (Bug #20949314,
        Bug #76810)

      * Partitioning: CREATE TABLE statements that used an
        invalid function in a subpartitioning expression did not
        always fail gracefully as expected. (Bug #20310212)

      * Partitioning: For an ordered index scan over multiple
        partitions, MySQL performs a merge sort across them using
        a priority queue whose entries hold pointers to buffers
        containing fetched rows. When all rows from all
        partitions are fetched, this queue is now empty. When
        this occurred, subsequent attempts to fetch rows were
        done by passing a null buffer pointer, which caused the
        server to fail. This could manifest itself when executing
        HANDLER ... READ ... PREV against a partitioned table.
        Now in such cases this pointer holds NO_CURRENT_PART_ID
        so that the partitioning handler is aware that the queue
        is empty. (Bug #20270687)

      * Partitioning: REPAIR TABLE ... QUICK could fail when used
        with multiple partitioned tables. (Bug #76154, Bug
        #20647894)

      * Partitioning: In certain cases, ALTER TABLE ... REBUILD
        PARTITION was not handled correctly when executed on a
        locked table. (Bug #75677, Bug #20437706)

      * Replication: Some replication thread statuses were not
        being shown in the PROCESSLIST_INFO column of the threads
        table. (Bug #21127308)

      * Replication: When using multiple replication channels,
        issuing RESET SLAVE on a non-default replication channel
        removes the channel, whereas issuing RESET SLAVE on the
        default replication channel does not remove the channel,
        as it always exists. In previous versions, this meant
        that the default replication channel did not correctly
        reset some configuration and status parameters. The fix
        ensures that issuing RESET SLAVE on the default
        replication channel resets all parameters. (Bug
        #21107331, Bug #21111229)

      * Replication: SHOW BINLOG EVENTS was not showing the
        correct statement for XA COMMIT ... ONE PHASE. Although
        the event was logged and replicated correctly, SHOW
        BINLOG EVENTS was showing an incorrect statement when
        handling the event. The fix ensures that the statement is
        correctly displayed. (Bug #21053526)

      * Replication: In MySQL 5.7.7 and earlier, GTIDs were
        automatically disabled whenever --initialize or
        --bootstrap were enabled. In MySQL 5.7.8 and later GTIDs
        are not disabled when --initialize or --bootstrap are
        enabled. (Bug #20980271)

      * Replication: When using mysql-test-run.pl with the
        --ps-protocol option to run a test against a server with
        log_bin=OFF, setting gtid_next and then executing a DDL
        statement caused an error. This was due to the DDL
        statement not being correctly logged to consume the GTID
        specified when setting gtid_next. (Bug #20954452)

      * Replication: When log_bin=ON, if a read-only XA
        transaction was prepared but had an empty body, a
        subsequent XA ROLLBACK caused an assertion. (Bug
        #20902763)

      * Replication: explicit_defaults_for_timestamp has been
        changed from a global variable to a global and session
        variable, and the session variable is now replicated.
        This means that you can change the variable and still be
        guaranteed that every statement uses the same value for
        the variable on master and slave, even if the variable is
        not changed synchronously on master and slave. (Bug
        #20866059)

      * Replication: When changing gtid_mode online, if
        autocommit was set to 0 and a set gtid_next=UUID:NUMBER
        statement had been issued, then changing gtid_mode was
        not being blocked. The fix ensures that variables which
        can only be set outside transaction context can now only
        be set if the thread does not own a GTID and does not
        hold anonymous ownership. This changes the behavior of
        these variables:

           + enforce_gtid_consistency

           + gtid_mode

           + gtid_purged

           + session_track_gtids
        (Bug #20865683)

      * Replication: mysqlbinlog would apply any rewrite rules
        before applying the database filter. This meant that in
        cases when statement-based replication transactions were
        mixed with row-based replication transactions only one or
        the other type of transaction would be output. The fix
        changes the behavior so that the rewrite rules also apply
        to the USE db_name clause, rewriting the database
        specified by db_name according to the setting of the
        --rewrite-db parameter. This makes it possible to use the
        --database option on the query and row events. In
        addition, it removes the suppression of the USE db_name
        statement and ensures that the rewrite is done before the
        database filter. (Bug #20810442)

      * Replication: When slaves, and especially semisynchronous
        replication slaves, connected to a master there was a
        chance they could encounter a SLAVE HAS MORE GTIDS THAN
        THE MASTER HAS error. During connection the slave sends
        all replicated GTIDs to the master, and the master checks
        if all the GTIDs matching its server_uuid are included in
        its gtid_executed GTID set. There was a chance that a
        GTID was already in the slave's gtid_executed GTID set,
        but not in the master's gtid_executed GTID set. This was
        due to the GTID being added into gtid_executed after it
        was added to the binary log, meaning it was possible that
        a transaction had been replicated and applied on the
        slave, but not committed on the master yet. The fix
        ensures that the master checks if all GTIDs are in the
        union of gtid_executed and gtid_owned. (Bug #20464737)

      * Replication: A replication slave running with a gtid_mode
        other than OFF, log_bin=OFF and
        relay_log_info_repository=TABLE was consuming the GTID of
        a transaction prematurely when applying a transaction
        that spanned across distinct relay log files. This was
        caused when the slave SQL thread was flushing the relay
        log information to the mysql.slave_relay_log_info table
        while in the middle of a transaction, or immediately
        after the GTID of a transaction, because of the rotation
        of the relay log. The fix skips saving the gtid_state for
        operations that save the relay log information to the
        mysql.slave_relay_log_info table. (Bug #20451386)

      * Replication: When gtid_mode=ON, issuing a SET
        gtid_next='UUID:NUMBER' statement and then issuing a
        statement that caused an error, such as CREATE..SELECT,
        led to an assertion failure on COMMIT. This was due to
        gtid_next being incorrectly set to undefined for
        implicitly committing statements, even if the statement
        failed with an error before the implicit commit happened.
        (Bug #20343644, Bug #20444828)

      * Replication: If a slave was restarted with
        --relay-log-recovery enabled and the initialization of
        the default replication channel had failed, a slave could
        refuse to start or cause an assert in debug mode. (Bug
        #20191813, Bug #20236305)

      * Replication: When using RESET MASTER, the GTID state
        (gtid_executed and gtid_purged) is reset. On a server
        with log_bin=OFF, using RESET MASTER fails because the
        binary log is not enabled. However, since MySQL 5.7.5,
        GTIDs can be enabled even when the binary log is
        disabled. So in this case there was no way to reset the
        GTID state. The fix ensures that RESET MASTER can be
        executed on a server with GTIDs enabled and log_bin=OFF,
        enabling you to reset the GTID state. (Bug #19706455)

      * Replication: If statement based logging was in use, when
        updating multiple tables in a single statement, a single
        transaction could be logged as two different
        transactions. This was due to the binary logging process
        not properly identifying statements which were operating
        over transactional tables. The fix ensures that they are
        correctly identified, even if such statements do not
        change the contents of the tables. (Bug #16621582)

      * Replication: When starting more than one instance of
        mysqld on the same host at the same time, the instances
        could get the same server_uuid. The fix uses settings
        unique to each started mysqld instance to ensure that
        each gets a unique UUID. (Bug #16459136)

      * Replication: If flushing the cache to the binary log
        failed, for example due to a disk problem, the error was
        not detected by the binary log group commit logic. This
        could cause inconsistencies between the master and the
        slave. The fix uses the binlog_error_action variable to
        decide how to handle this situation. If
        binlog_error_action=ABORT_SERVER, then the server aborts
        after informing the client with an
        ER_BINLOGGING_IMPOSSIBLE error. If
        binlog_error_action=IGNORE_ERROR, then the error is
        ignored and binary logging is disabled until the server
        is restarted again. The same is mentioned in the error
        log file, and the transaction is committed inside the
        storage engine without being added to the binary log.
        (Bug #76795, Bug #20938915)

      * Replication: When a slave was stopped,
        replication_applier_status_by_worker showed worker_id as
        1 and did not show the correct number. (Bug #76637, Bug
        #20857660)

      * Replication: Setting SESSION.GTID_NEXT=default
        immediately after setting SESSION.GTID_NEXT='ANONYMOUS'
        causes an ER_CANT_SET_GTID_NEXT_WHEN_OWNING_GTID error,
        but this also changes the gtid_next type from ANONYMOUS
        to AUTOMATIC, meaning that the next transaction could
        potentially cause an GTID_NEXT->TYPE != AUTOMATIC_GROUP
        || THD->OWNED_GTID.IS_EMPTY() assertion. To avoid this
        possibility, the fix ensures that setting
        SESSION.GTID_NEXT=default does not change the gtid_next
        type if it could cause an error. (Bug #76434, Bug
        #20753378)

      * Replication: Additional replication channels could not be
        added if the server had been started with server_id=0,
        the default. The fix ensures that a replication slave
        checks the server_id is greater than 0 when CHANGE MASTER
        TO has been issued before continuing with the
        initialization of a channel. (Bug #76432, Bug #20753463,
        Bug #20712720)

      * Replication: When a server was configured with
        gtid_mode=ON, log-bin=OFF, and with autocommit enabled,
        during commit it was possible to encounter an ASSERTION
        `IS_STARTED()' FAILED error. This was possible when an
        applier thread committed a transaction's GTID into the
        gtid_executed table before transaction prepare when
        binary logging was disabled, or binary logging was
        enabled and log_slave_updates was disabled. The cause was
        that when the server was saving a transaction's GTID into
        the gtid_executed table, the calculated transaction
        context could be committed during the save phase when
        autocommit was enabled. The fix ensures that the
        transaction context is calculated after saving the GTID's
        state, and then commit is executed on any remaining
        transactions. (Bug #76425, Bug #20748570)

      * Replication: When using row-based logging with autocommit
        disabled and GTID_MODE=OFF_PERMISSIVE, if a transaction
        started with a CREATE TEMPORARY TABLE statement, then
        regardless of whether the table was transactional or
        non-transactional, the transaction began an automatic
        GTID violating transaction. However, if
        GTID_NEXT='UUID:NUMBER' was issued immediately after
        executing the CREATE TEMPORARY TABLE statement, which
        sets gtid_next type to GTID_GROUP, upon committing the
        transaction, a check for possible violation of GTID
        consistency was causing an assertion failure because the
        gtid_next type had been changed from AUTOMATIC_GROUP to
        GTID_GROUP.
        The fix ensures that transactions with an empty owned
        GTID correctly check if they break GTID consistency. As
        part of this fix, it was found that when autocommit was
        disabled, the statement CREATE TEMPORARY TABLE did not
        start a transaction, so immediately setting
        GTID_NEXT='UUID:NUMBER' could not cause an error. The fix
        ensures that when autocommit is disabled, executing
        CREATE TEMPORARY TABLE or DROP TEMPORARY TABLE starts a
        transaction, regardless of the state of log_bin,
        binlog_format and whether a transactional or
        non-transactional storage engine is in use. This makes
        the behavior consistent, but is a change in logging when
        log-bin=OFF. (Bug #76416, Bug #20748502)

      * Replication: When using GTIDs with log-bin=OFF, a
        combination of statements which included a BINLOG
        statement executing a Format_description_log_event would
        cause an assertion. The reason was that the server would
        run the routine to handle the end of a GTID violating
        transaction, which was incorrect because when
        --log-bin=OFF the transaction should not have been
        handled as an offending transaction. The fix ensures that
        before the compatibility testing, the state of log_bin is
        checked. If log_bin=OFF, then the compatibility checks
        are skipped. This makes the server not activate flags
        that would then trigger the incorrect run of the routine
        to handle GTID violating transactions that ultimately
        resulted in an assertion. (Bug #76406, Bug #20743468)

      * Replication: When binary logging was enabled, using
        stored functions and triggers resulting in a long running
        procedure that inserted many records caused the memory
        use to increase rapidly. This was due to memory being
        allocated per variable. The fix ensures that in such a
        situation, memory is allocated once and the same memory
        is reused. (Bug #75879, Bug #20531812)

      * Replication: If an error occurred when using a
        multi-threaded slave, issuing a CHANGE MASTER TO
        statement which resulted in an
        ER_MTS_CHANGE_MASTER_CANT_RUN_WITH_GAPS error, and then
        issuing RESET SLAVE, made it impossible to change master
        due to repeated ER_MTS_CHANGE_MASTER_CANT_RUN_WITH_GAPS
        errors. Running the debug version of mysqld caused an
        unexpected exit in this case. The fix ensures that the
        recovery process for multi-threaded slaves avoids this.
        (Bug #75574, Bug #20411374)

      * Replication: When using semisynchronous replication
        performance was degrading when the number of threads
        increased beyond a certain threshold. To improve
        performance, now only the thread which is committing is
        responsible for deleting the active transaction node. All
        other operations do not touch this active transaction
        list. (Bug #75570, Bug #20574628)

      * Replication: When gtid_executed_compression_period is set
        to a number greater than 0, there is a thread that wakes
        up after every number of transactions specified by
        gtid_executed_compression_period to perform range
        compression on the mysql.gtid_executed table. There was a
        small chance that the thread would miss a signal and not
        wake up, so that one pass of the compression algorithm
        would be missed and the table left uncompressed. The fix
        ensures that the thread wakes up consistently. (Bug
        #75014, Bug #20104307)

      * Replication: Using mysqlbinlog to process log events
        greater than 1.6GB failed with an out of memory error.
        This was caused by an internal error converting the
        length variable. The fix upgrades the length variable to
        avoid overflow in both encoding and decoding functions.
        (Bug #74734, Bug #20350989)

      * Replication: Setting gtid_next inside a stored procedure
        and committing an empty transaction caused an error. This
        was due to the empty transaction not being correctly
        logged to consume the GTID specified by setting
        gtid_next. (Bug #74253, Bug #19774317)

      * Replication: Some messages that were meant to be printed
        when log_warnings was greater than 1 started appearing in
        the error log. The information regarding the
        multi-threaded applier in particular was too verbose and
        much of this information was very technical and
        development oriented. The fix ensures that these messages
        are not logged. (Bug #74203, Bug #19729278)

      * Replication: When using a multi-threaded slave with
        slave_preserve_commit_order=1, certain combinations of
        transactions being applied in parallel could cause a
        deadlock and stop the slave responding. The fix
        introduces a check for such deadlocks, so that when a
        transaction needs to wait for another transaction to
        release a row lock, InnoDB checks if there is a deadlock
        caused by the commit order. If it finds a deadlock caused
        by the commit order, it sets a deadlock flag for the
        slave worker which is holding the row lock. Then the
        worker rolls back its transaction and tries again. (Bug
        #74177, Bug #20136704)

      * Replication: When a master with --binlog_checksum=none
        and --gtid-mode=ON was replicating to a slave with
        --binlog_checksum=crc32, restarting the slave's SQL
        thread caused an Event crc check error. This was due to
        the Format_description_log_event from the master not
        being correctly found in existing relay logs after
        restarting the slave's SQL thread. The fix ensures that
        the Previous_gtids_log_event is correctly skipped and
        that the correct Format_description_log_event is found in
        existing relay logs after restarting the slave's SQL
        thread. (Bug #73806, Bug #20644100)

      * Replication: When gtid_mode=on, GTIDs are automatically
        added to the mysql.gtid_executed table. If a GTID was
        manually inserted into the mysql.gtid_executed table and
        then automatic update inserted the same GTID, the server
        crashed. Manually inserting GTIDs into
        mysql.gtid_executed is an unsupported operation, but this
        fix ensures that the server does not crash in such a
        situation. (Bug #73601, Bug #19451053)

      * Replication: When using GTIDs, a multi-threaded slave
        which had relay_log_recovery=1 and that stopped
        unexpectedly could encounter a relay-log-recovery cannot
        be executed when the slave was stopped with an error or
        killed in MTS mode error upon restart. The fix ensures
        that the relay log recovery process checks if GTIDs are
        in use or not. If GTIDs are in use, the multi-threaded
        slave recovery process uses the GTID protocol to fill any
        unprocessed transactions. (Bug #73397, Bug #19316063)

      * Replication: When master_info_repository=TABLE the
        receiver thread stores received event information in a
        table. The memory used in the process of updating the
        table was not being freed correctly and this could lead
        to an out of memory error. The fix ensures that after an
        event is flushed to the relay log file by a receiver
        thread, the memory used is freed. (Bug #72885, Bug
        #19390463, Bug #69848, Bug #20124342)

      * Replication: The status variables
        Rpl_semi_sync_master_net_wait_time and
        Rpl_semi_sync_master_net_avg_wait_time were always 0 in
        MySQL 5.7.4 and later. These variables are now deprecated
        and will be removed in a future version. (Bug #72627, Bug
        #18750614)

      * Replication: When two slaves with the same server_uuid
        were configured to replicate from a single master, the
        I/O thread of the slaves kept reconnecting and generating
        new relay log files without new content. In such a
        situation, the master now generates an error which is
        sent to the slave. By receiving this error from the
        master, the slave I/O thread does not try to reconnect,
        avoiding this problem. (Bug #72581, Bug #18731252)

      * Replication: If a slave encountered a
        ER_NET_READ_INTERRUPTED or ER_NET_WRITE_INTERRUPTED error
        while getting a timestamp or server ID from the master,
        setting MASTER_HEARTBEAT_PERIOD and so on, the slave's
        receiver thread stopped. The fix ensures that these
        errors are treated as transient network errors, and the
        slave receiver thread attempts to automatically reconnect
        to the master in such a situation. (Bug #71374, Bug
        #18091217)



Thread
MySQL Community Server 5.7.8 has been released (part 2/3)Balasubramanian Kandasamy3 Aug