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From:Hery Ramilison Date:April 11 2011 1:38pm
Subject:MySQL Community Server 5.6.2 has been released
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Dear MySQL users,


MySQL Server 5.6.2 (Milestone Release) is a new version of the world's
most popular open source database.

The new features in these releases are of beta quality. As with any
other pre-production release, caution should be taken when installing on
production level systems or systems with critical data.

Note that 5.6.2 includes all features in MySQL 5.5. For an overview of
what's new in MySQL 5.6, please see the section "What Is New in MySQL
5.6" below, or view it online at

     http://dev.mysql.com/doc/refman/5.6/en/mysql-nutshell.html

For information on installing MySQL 5.6.2 on new servers, please see the
MySQL installation documentation at

     http://dev.mysql.com/doc/refman/5.6/en/installing.html

For upgrading from previous MySQL releases, please see the important
upgrade considerations at

http://dev.mysql.com/doc/refman/5.6/en/upgrading-from-previous-series.html

Please note that *downgrading* from these releases to a previous release
series is not supported.

MySQL Server 5.6 is available in source and binary form for a number of
platforms from the "Development Releases" selection of our download
pages at

     http://dev.mysql.com/downloads/mysql/

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.:

      http://forge.mysql.com/wiki/Contributing

The list of all "Bugs Fixed" for 5.6.2 may also be viewed online at

      http://dev.mysql.com/doc/refman/5.6/en/news-5-6-2.html

If you are running a MySQL production level system, we would like to
direct your attention to MySQL Enterprise Edition, which includes the
most comprehensive set of MySQL production, backup, monitoring,
modeling, development, and administration tools so businesses can
achieve the highest levels of MySQL performance, security and uptime.

      http://mysql.com/products/enterprise/


D.1.2. Changes in MySQL 5.6.2 (11 April 2011)

    Explicit Partition Selection

      * Partitioning: It is now possible to select one or more
        partitions or subpartitions when querying from a partitioned
        table. In addition, many data modification statements (DELETE,
        INSERT, REPLACE, UPDATE, LOAD DATA, and LOAD XML) that act on
        partitioned tables also now support explicit partition
        selection. For example, assume we have a table named t with
        some integer column named c, and t has 4 partitions named p0,
        p1, p2, and p3. Then the query SELECT * FROM t PARTITION (p0,
        p1) WHERE c < 5 returns rows only in partitions p0 and p1 that
        match the WHERE condition, while partitions p2 and p3 are not
        checked.
        For additional information and examples, see Section 16.5,
        "Partition Selection," as well as the descriptions of the
        statements just listed.

    Row Image Control

      * Replication: Added the binlog_row_image server system
        variable, which can be used to enable row image control for
        row-based replication. This means that you can potentially
        save disk space, network resources, and memory usage by the
        MySQL Server by logging only those columns that are required
        for uniquely identifying rows, or which are actually changed
        on each row, as opposed to logging all columns for each and
        every row change event. In addition, you can use a "noblob"
        mode where all columns, except for unneeded BLOB or TEXT
        columns, are logged.
        For more information, see Section 15.1.3.4, "System variables
        used with the binary log." (Bug #47200, Bug #11755426, Bug
        #47303, Bug #56917, Bug #11755426, Bug #11755513, Bug
        #11764116)

    Crash-Safe Binary Log

      * Replication: Support for checksums when writing and reading
        the binary log is added to the MySQL Server. Writing checksums
        into the binary log is disabled by default; it can be enabled
        by starting the server with the --binlog-checksum option. To
        cause the server to read checksums from the binary log, start
        the server with the --master-verify-checksum option. The
        --slave-sql-verify-checksum option causes the slave to read
        checksums from the relay log.

      * Replication: The MySQL Server now records and reads back only
        complete events or transactions to and from the binary log. By
        default, the server now logs the length of the event as well
        as the event itself and uses this information to verify that
        the event was written correctly to the log. A master also uses
        by default this value to verify events when reading from the
        binary log.
        If you enable writing of checksums (using the binlog_checksum
        system variable), the master can use these instead by enabling
        the master_verify_checksum system variable. The slave I/O
        thread also verifies events received from the master. You can
        cause the slave SQL thread to use checksums (if available) as
        well, when reading from the relay log, by enabling the
        slave_sql_verify_checksum system variable on the slave.

    Slave Log Tables

      * Replication: It is now possible to write information about the
        slave connection to the master and about the slave's execution
        point within the relay log to tables rather than files.
        Logging of master connection information and of slave relay
        log information to tables can be done independently of one
        another; this is controlled by the --master-info-repository
        and --relay-log-info-repository server options. When
        --master-info-repository is set to TABLE, connection
        information is logged in the slave_master_info table in the
        mysql system database. When --relay-log-info-repository is set
        to TABLE, relay log information is logged to the
        slave_relay_log_info table, also in the mysql database.

    Globally Unique Server IDs

      * Replication: Implemented globally unique IDs for MySQL
        servers. A UUID is now obtained automatically when the MySQL
        server starts. The server first checks for a UUID written in
        the auto.cnf file (in the server's data directory), and uses
        this UUID if found. Otherwise, the server generates a new UUID
        and saves it to this file (and creates the file if it does not
        already exist). This UUID is available as the server_uuid
        system variable.
        MySQL replication masters and slaves know each other's UUIDs.
        The value of a slave's UUID can be read on the master as the
        system variable slave_uuid, as well as in the output of SHOW
        SLAVE HOSTS. After a slave is started (with START SLAVE), the
        value of the master's UUID is available on the slave as the
        master_uuid system variable, as well as in the output of SHOW
        SLAVE STATUS.
        For more information, see Section 15.1.3, "Replication and
        Binary Logging Options and Variables." (Bug #33815, Bug
        #11747723)
        See also Bug #16927, Bug #11745543.

    Optimizer Features

      * The optimizer now more efficiently handles queries (and
        subqueries) of the following form:
         SELECT ... FROM single_table ... ORDER BY non_index_column
         [DESC] LIMIT N;
        That type of query is common in web applications that display
        only a few rows from a larger result set. For example:
         SELECT col1, ... FROM t1 ... ORDER BY name LIMIT 10;
         SELECT col1, ... FROM t1 ... ORDER BY RAND() LIMIT 15;
        If the sort elements for N rows are small enough to fit in the
        sort buffer, which has a size of sort_buffer_size, the server
        can avoid using a merge file and perform the sort entirely in
        memory. For details, see Section 7.2.1.3, "Optimizing LIMIT
        Queries."

      * The optimizer implements Disk-Sweep Multi-Range Read. Reading
        rows using a range scan on a secondary index can result in
        many random disk accesses to the base table when the table is
        large and not stored in the storage engine's cache. With the
        Disk-Sweep Multi-Range Read (MRR) optimization, MySQL tries to
        reduce the number of random disk access for range scans by
        first scanning the index only and collecting the keys for the
        relevant rows. Then the keys are sorted and finally the rows
        are retrieved from the base table using the order of the
        primary key. The motivation for Disk-sweep MRR is to reduce
        the number of random disk accesses and instead achieve a more
        sequential scan of the base table data. For more information,
        see Section 7.13.10, "Multi-Range Read Optimization."

      * The optimizer implements Index Condition Pushdown (ICP), an
        optimization for the case where MySQL retrieves rows from a
        table using an index. Without ICP, the storage engine
        traverses the index to locate rows in the base table and
        returns them to the MySQL server which evaluates the WHERE
        condition for the rows. With ICP enabled, and if parts of the
        WHERE condition can be evaluated by using only fields from the
        index, the MySQL server pushes this part of the WHERE
        condition down to the storage engine. The storage engine then
        evaluates the pushed index condition by using the index entry
        and only if this is satisfied is base row be read. ICP can
        reduce the number of accesses the storage engine has to do
        against the base table and the number of accesses the MySQL
        server has to do against the storage engine. For more
        information, see Section 7.13.4, "Index Condition Pushdown
        Optimization."

    Performance Schema Notes

      * The Performance Schema has these additions:

           + The Performance Schema now has tables that contain
             summaries for table and index I/O wait events, as
             generated by the wait/io/table/sql/handler instrument:
                o table_io_waits_summary_by_table aggregates table I/O
                  wait events. The grouping is by table.
                o table_io_waits_summary_by_index_usage aggregates
                  table index I/O wait events. The grouping is by
                  table index.
             The information in these tables can be used to assess the
             impact of table I/O performed by applications. For
             example, it is possible to see which tables are used and
             which indexes are used (or not used), or to identify
             bottlenecks on a table when multiple applications access
             it. The results may be useful to change how applications
             issue queries against a database, to minimize application
             footprint on the server and to improve application
             performance and scalability.
             A change that accompanies the new tables is that the
             events_waits_current table now has an INDEX_NAME column
             to identify which index was used for that operation that
             generated the event. The same is true of the
             event-history tables, events_waits_history, and
             events_waits_history_long.

           + The Performance Schema now has an instrument named
             wait/lock/table/sql/handler in the setup_instruments
             table for instrumenting table lock wait events. It
             differs from wait/io/table/sql/handler, which instruments
             table I/O. This enables independent instrumentation of
             table I/O and table locks.
             Accompanying the new instrument, the Performance Schema
             has a table named table_lock_waits_summary_by_table that
             aggregates table lock wait events, as generated by the
             new instrument. The grouping is by table.
             The information in this table may be used to assess the
             impact of table locking performed by applications. The
             results may be useful to change how applications issue
             queries against the database and use table locks, to
             minimize the application footprint on the server and to
             improve application performance and scalability. For
             example, an application locking tables for a long time
             may negatively affect other applications, and the
             instrumentation makes this visible.

           + To selectively control which tables are instrumented for
             I/O and locking, use the setup_objects table. See Section
             19.3.1.2, "Pre-Filtering by Object."

           + The setup_consumers table contents have changed.
             Previously, the table used a "flat" structure with a
             one-to-one correspondence between consumer name and
             destination table. This has been replaced with a
             hierarchy of consumer settings that enable progressively
             finer control of which destinations receive events. The
             previous xxx_summary_xxx consumers no longer exist.
             Instead, the Performance Schema maintains appropriate
             summaries automatically for the levels are which settings
             in the consumer hierarchy are enabled. For example, if
             only the top-level (global) consumer is enabled, only
             global summaries are maintained. Others, such as
             thread-level summaries, are not. See Section 19.3.1.4,
             "Pre-Filtering by Consumer." In addition, optimizations
             have been added to reduce Performance Schema overhead.

           + It is now possible to filter events by object using the
             new setup_objects table. Currently, this table can be
             used to selectively instrument tables, based on schema
             names and/or table names. See Section 19.3.1.2,
             "Pre-Filtering by Object." A new table,
             objects_summary_global_by_type, summarizes events for
             objects.

           + It is now possible to filter events by thread, and the
             Performance Schema collects more information for each
             thread. A new table, setup_actors, can be used to
             selectively instrument user connections, based on the
             user name and/or host name of each connecting session.
             The threads table, which contains a row for each active
             server thread, was extended with several new columns.
             With these additions, the information available in
             threads is like that available from the
             INFORMATION_SCHEMA.PROCESSLIST table or the output from
             SHOW PROCESSLIST. Thus, all three serve to provide
             information for thread-monitoring purposes. Use of
             threads differs from use of the other two thread
             information sources in these ways:
                o Access to threads does not require a mutex and has
                  minimal impact on server performance.
                  INFORMATION_SCHEMA.PROCESSLIST and SHOW PROCESSLIST
                  have negative performance consequences because they
                  require a mutex.
                o threads provides additional information for each
                  thread, such as whether it is a foreground or
                  background thread, and the location within the
                  server associated with the thread.
                o threads provides information about background
                  threads. This means that threads can be used to
                  monitor activity the other thread information
                  sources cannot.
                o You can control which threads are monitored by
                  setting the INSTRUMENTED column or by using the
                  setup_actors table.
             For these reasons, DBAs who perform server monitoring
             using INFORMATION_SCHEMA.PROCESSLIST or SHOW PROCESSLIST
             may wish to monitor using threads instead.

        If you upgrade to this release of MySQL from an earlier
        version, you must run mysql_upgrade (and restart the server)
        to incorporate these changes into the performance_schema
        database.
        For more information, see Chapter 19, "MySQL Performance
        Schema."


    Functionality added or changed:

      * Incompatible Change: The following obsolete constructs have
        been removed. Where alternatives are shown, applications
        should be updated to use them.

           + The FLUSH MASTER and FLUSH SLAVE statements. Use the
             RESET MASTER and RESET SLAVE statements instead.

           + The --log server option and the log system variable.
             Instead, use the --general_log option to enable the
             general query log and the --general_log_file=file_name
             option to set the general query log file name.

           + The --log-slow-queries server option and the
             log_slow_queries system variable. Instead, use the
             --slow_query_log option to enable the slow query log and
             the --slow_query_log_file=file_name option to set the
             slow query log file name.

           + The --one-thread server option. Use
             --thread_handling=no-threads instead.

           + The --skip-thread-priority server option.

           + The engine_condition_pushdown system variable. Use the
             engine_condition_pushdown flag of the optimizer_switch
             variable instead.

           + The have_csv, have_innodb, have_ndbcluster
             (http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-sys
             tem-variables.html#sysvar_have_ndbcluster), and
             have_partitioning system variables. Use SHOW ENGINES
             instead.

           + The sql_big_tables system variable. Use big_tables
             instead.

           + The sql_low_priority_updates system variable. Use
             low_priority_updates instead.

           + The sql_max_join_size system variable. Use max_join_size
             instead.

           + The SLAVE START and SLAVE STOP statements. Use the START
             SLAVE and STOP SLAVE statements instead.

           + The ONE_SHOT modifier for the SET statement.

      * Important Change: Replication: Replication filtering options
        such as --replicate-do-db, --replicate-rewrite-db, and
        --replicate-do-table were not consistent with one another in
        regard to case sensitivity. Now all --replicate-* options
        follow the same rules for case sensitivity applying to names
        of databases and tables elsewhere in the MySQL server,
        including the effects of the lower_case_table_names system
        variable. (Bug #51639, Bug #11759334)

      * Important Change: Replication: Added the MASTER_RETRY_COUNT
        option to the CHANGE MASTER TO statement, and a corresponding
        Master_Retry_Count column to the output of SHOW SLAVE STATUS.
        The option sets the value shown in this column.
        MASTER_RETRY_COUNT is intended eventually to replace the older
        --master-retry-count server option, and is now the preferred
        method for setting the maximum number of times that the slave
        may attempt to reconnect after losing its connection to the
        master. (Bug #44209, Bug #11752887, Bug #44486, Bug #11753110)

      * Important Change: Replication: Added the
        --binlog-rows-query-log-events option for mysqld. Using this
        option causes a server logging in row-based mode to write
        informational rows query log events (SQL statements, for
        debugging and other purposes) to the binary log. MySQL server
        and MySQL programs from MySQL 5.6.2 and later normally ignore
        such events, so that they do not pose an issue when reading
        the binary log. mysqld and mysqlbinlog from previous MySQL
        releases cannot read such events in the binary log, and fail
        if they attempt to do so. For this reason, you should never
        prepare logs for a MySQL 5.6.1 or earlier replication slave
        server (or other reader such as mysqlbinlog) with this option
        enabled on the master. (Bug #11758695, Bug #50935, Bug
        #11758695)

      * Replication: SHOW SLAVE STATUS now displays the actual number
        of retries for each connection attempt made by the I/O thread.
        (Bug #56416, Bug #11763675)

      * Replication: Added the Slave_last_heartbeat status variable,
        which shows when a replication slave last received a heartbeat
        signal. The value is displayed using TIMESTAMP format. (Bug
        #45441)

      * Replication: Timestamps have been added to the output of SHOW
        SLAVE STATUS to show when the most recent I/O and SQL thread
        errors occurred. The Last_IO_Error column is now prefixed with
        the timestamp for the most recent I/O error, and
        Last_SQL_Error shows the timestamp for the most recent SQL
        thread error. The timestamp values use the format YYMMDD
        HH:MM:SS in both of these columns. For more information, see
        Section 12.4.5.35, "SHOW SLAVE STATUS Syntax." (Bug #43535,
        Bug #11752361)

      * Replication: On MySQL replication slaves having multiple
        network interfaces, it is now possible to set which interface
        to use for connecting to the master using the
        MASTER_BIND='interface' option in a CHANGE MASTER TO
        statement.
        The value set by this option can be seen in the Master_Bind
        column of the output from SHOW SLAVE STATUS or the Bind column
        of the mysql.slave_master_info table. (Bug #25939, Bug
        #11746389)

      * Replication: Added the log_bin_basename system variable, which
        contains the complete filename and path to the binary log
        file. (The log_bin system variable shows only whether or not
        binary logging is enabled; log_bin_basename, however, reflects
        the name set with the --log-bin server option.) Also added
        relay_log_basename system variable, which shows the filename
        and complete path to the relay log file.
        See also Bug #19614, Bug #11745759.

      * Changes to replication in MySQL 5.6 make mysqlbinlog output
        generated by the --base64-output=ALWAYS option unusable.
        ALWAYS is now an invalid value for this option. If the option
        is given without a value, the effect is now the same as
        --base64-output=AUTO rather than --base64-output=ALWAYS.
        See also Bug #28760, Bug #11746794.

      * Replication: The SHOW SLAVE STATUS statement now has a
        Master_Info_File field indicating the location of the
        master.info file. (Bug #50316, Bug #11758151)

      * Replication: MySQL now supports delayed replication such that
        a slave server deliberately lags behind the master by at least
        a specified amount of time. The default delay is 0 seconds.
        Use the new MASTER_DELAY option for CHANGE MASTER TO to set
        the delay to N seconds:
         CHANGE MASTER TO MASTER_DELAY = N;
        An event received from the master is not executed until at
        least N seconds later than its execution on the master.
        START SLAVE and STOP SLAVE take effect immediately and ignore
        any delay. RESET SLAVE resets the delay to 0.
        SHOW SLAVE STATUS has three new fields that provide
        information about the delay:

           + SQL_Delay: The number of seconds that the slave must lag
             the master.

           + SQL_Remaining_Delay: When Slave_SQL_Running_State is
             Waiting until MASTER_DELAY seconds after master executed
             event, this field contains the number of seconds left of
             the delay. At other times, this field is NULL.

           + Slave_SQL_Running_State: The state of the SQL thread
             (analogous to Slave_IO_State). The value is identical to
             the State value of the SQL thread as displayed by SHOW
             PROCESSLIST.
        When the slave SQL thread is waiting for the delay to elapse
        before executing an event, SHOW PROCESSLIST displays its State
        value as Waiting until MASTER_DELAY seconds after master
        executed event.
        The relay-log.info file now contains the delay value, so the
        file format has changed. See Section 15.2.2.2, "Slave Status
        Logs." In particular, the first line of the file now indicates
        how many lines are in the file. If you downgrade a slave
        server to a version older than MySQL 5.6, the older server
        will not read the file correctly. To address this, modify the
        file in a text editor to delete the initial line containing
        the number of lines.
        The introduction of delayed replication entails these
        restrictions:

           + Previously the BINLOG statement could execute all types
             of events. Now it can execute only format description
             events and row events.

           + The output from mysqlbinlog --base64-output=ALWAYS cannot
             be parsed. ALWAYS becomes an invalid value for this
             option in 5.6.1.
        For additional information, see Section 15.3.9, "Delayed
        Replication." (Bug #28760, Bug #11746794)

      * The Performance Schema now includes instrumentation for table
        input and output. Instrumented operations include row-level
        accesses to persistent base tables or temporary tables.
        Operations that affect rows are fetch, insert, update, and
        delete. For a view, waits are associated with base tables
        referenced by the view.

      InnoDB Configurable Data Dictionary cache

      * InnoDB Storage Engine: InnoDB now uses the table_cache option
        value as a guide to remove table metadata from memory when
        many different InnoDB tables are accessed. InnoDB table
        metadata is removed using a variation of the LRU algorithm.
        (Parent and child tables in foreign key relationships are
        exempted from removal.) (Bug #20877, Bug #11745884)

      INFORMATION_SCHEMA Table for InnoDB Metrics

      * InnoDB Storage Engine: A new INFORMATION_SCHEMA table,
        INNODB_METRICS, lets you query low-level InnoDB performance
        information, getting cumulative counts, averages, and min/max
        values for internal aspects of the storage engine operation.
        You can start, stop, and reset the metrics counters using the
        configuration variables innodb_monitor_enable,
        innodb_monitor_disable, innodb_monitor_reset, and
        innodb_monitor_reset_all.

      INFORMATION_SCHEMA Tables for InnoDB Buffer Pool Information

      * InnoDB Storage Engine: The new INFORMATION_SCHEMA tables
        INNODB_BUFFER_PAGE, INNODB_BUFFER_PAGE_LRU, and
        INNODB_BUFFER_POOL_STATS display InnoDB buffer pool
        information for tuning on large-memory or highly loaded
        systems.

      INFORMATION_SCHEMA Tables for InnoDB Data Dictionary

      * InnoDB Storage Engine: The InnoDB data dictionary, containing
        metadata about InnoDB tables, columns, indexes, and foreign
        keys, is available for SQL queries through a set of
        INFORMATION_SCHEMA tables.

      Persistent InnoDB Optimizer Statistics

      * InnoDB Storage Engine: The optimizer statistics for InnoDB
        tables can now persist across server restarts, producing more
        stable query performance. You can also control the amount of
        sampling done to estimate cardinality for each index,
        resulting in more accurate optimizer statistics.

      * InnoDB Storage Engine: InnoDB can optionally log details about
        all deadlocks that occur, to assist with troubleshooting and
        diagnosis. This feature is controlled by the
        innodb_print_all_deadlocks configuration option. (Bug #1784,
        , Bug #11744783, Bug #17572)

      * InnoDB Storage Engine: A separate InnoDB thread (page_cleaner)
        now handles the flushing of dirty pages that was formerly done
        by the InnoDB master thread.

      * InnoDB Storage Engine: The configuration option
        innodb_purge_threads can now be set to a value higher than 1.

      * InnoDB Storage Engine: The InnoDB kernel mutex has been split
        into several mutexes and rw-locks, for improved concurrency.

      * Windows provides APIs based on UTF-16LE for reading from and
        writing to the console. MySQL now supports a utf16le character
        set for UTF-16LE, so the mysql client for Windows has been
        modified to provide improved Unicode support by using these
        APIs.
        To take advantage of this change, you must run mysql within a
        console that uses a compatible Unicode font and set the
        default character set to a Unicode character set that is
        supported for communication with the server. For instructions,
        see Section 4.5.1.6.1, "Unicode Support on Windows."

      * Several changes were made to optimizer-related system
        variables:

           + The optimizer_switch system variable has new
             engine_condition_pushdown and index_condition_pushdown
             flags to control whether storage engine condition
             pushdown and index condition pushdown optimizations are
             used. The engine_condition_pushdown system variable now
             is deprecated. For information about condition pushdown,
             see Section 7.13.3, "Engine Condition Pushdown
             Optimization," and Section 7.13.4, "Index Condition
             Pushdown Optimization."

           + The optimizer_switch system variable has new mrr and
             mrr_cost_based flags to control use of the Multi-Range
             Read optimization. The optimizer_use_mrr system variable
             has been removed. For information about Multi-Range Read,
             see Section 7.13.10, "Multi-Range Read Optimization."

           + The join_cache_level system variable has been renamed to
             optimizer_join_cache_level. This enables SHOW VARIABLES
             LIKE 'optimizer%' to show more optimizer-related
             settings.

      * In MySQL 5.5, setting optimizer_search_depth to the deprecated
        value of 63 switched to the algorithm used in MySQL 5.0.0 (and
        previous versions) for performing searches. The value of 63 is
        now treated as invalid.


      * The Unicode implementation has been extended to a utf16le
        character set, which corresponds to the UTF-16LE encoding of
        the Unicode character set. This is similar to utf16 (UTF16)
        but is little-endian rather than big-endian.
        utf16le has two collations available:

           + utf16le_general_ci: The default collation, case sensitive
             (similar to utf16_general_ci.

           + utf16le_bin: Case sensitive, with by-codepoint comparison
             that provides the same order as utf16_bin.
        There are some limitations on the use of utf16le. With the
        exception of the item regarding user-defined collations, these
        are the same as the limitations on ucs2, utf16, and utf32.

           + utf16le cannot be used as a client character set, which
             means that it also does not work for SET NAMES or SET
             CHARACTER SET.

           + It is not possible to use LOAD DATA INFILE to load data
             files that use utf16le.

           + FULLTEXT indexes cannot be created on a column that uses
             utf16le. However, you can perform IN BOOLEAN MODE
             searches on the column without an index.

           + The use of ENCRYPT() with utf16le is not recommended
             because the underlying system call expects a string
             terminated by a zero byte.

           + It is not possible to create user-defined UCA collations
             for utf16le because there is no utf16le_unicode_ci
             collation, which would serve as the basis for such
             collations.

      * Unicode collation names now may include a version number to
        indicate the Unicode Collation Algorithm (UCA) version on
        which the collation is based. Initial collations thus created
        use version UCA 5.2.0. For example, utf8_unicode_520_ci is
        based on UCA 5.2.0. UCA-based Unicode collation names that do
        not include a version number are based on version 4.0.0.
        LOWER() and UPPER() perform case folding according to the
        collation of their argument. A character that has uppercase
        and lowercase versions only in a Unicode version more recent
        than 4.0.0 will be converted by these functions only if the
        argument has a collation that uses a recent enough UCA
        version.
        The LDML rules for creating user-defined collations are
        extended to permit an optional version attribute in
        <collation> tags to indicate the UCA version on which the
        collation is based. If the version attribute is omitted, its
        default value is 4.0.0. See Section 9.4.4, "Adding a UCA
        Collation to a Unicode Character Set."

      * Croatian collations were added for Unicode character sets:
        utf8_croatian_ci, ucs2_croatian_ci, utf8mb4_croatian_ci,
        utf16_croatian_ci, and utf32_croatian_ci. Thee collations have
        tailoring for Croatian letters: Č, Ć, Dž,
Ä        They are based on Unicode 4.0.

      * Vietnamese collations were added for the Unicode character
        sets. Those based on Unicode Collation Algorithm 5.2.0 have
        names of the form xxx_vietnamese_520_ci (for example,
        utf8_vietnamese_520_ci). Those based on Unicode Collation
        Algorithm 4.0.0 have names of the form xxx_vietnamese_ci (for
        example, utf8_vietnamese_ci). These collations are the same as
        the corresponding xxx_unicode_520_ci and xxx_unicode_ci
        collations except for precomposed characters which are
        accented versions of "A", "D", "E", "O", and "U". There is no
        change to ideographic characters derived from Chinese. There
        are no digraphs.


      * The Unicode character sets now have a xxx_german2_ci collation
        that provides DIN-2 (phone book) ordering (for example,
        utf8_german2_ci). See Section 9.1.14.1, "Unicode Character
        Sets."

      * The Romansh locale 'rm_CH' is now a permissible value for the
        lc_time_names system variable. (Bug #50915, Bug #11758678)

      * Partitioning: It is now possible to exchange a partition of a
        partitioned table or a subpartition of a subpartitioned table
        with a nonpartitioned table that otherwise has the same
        structure using the ALTER TABLE ... EXCHANGE PARTITION
        statement. This can be used, for example, for importing and
        exporting partitions.
        For more information and examples, see Section 16.3.3,
        "Exchanging Partitions and Subpartitions with Tables."

      * The mysql_upgrade, mysqlbinlog, mysqlcheck, mysqlimport,
        mysqlshow, and mysqlslap clients now have --default-auth and
        --plugin-dir options for specifying which authentication
        plugin and plugin directory to use. (Bug #58139, Bug #11765201)

      * mysqlbinlog now has a --binlog-row-event-max-size option to
        enable large row events to be read from binary log files. (Bug
        #49932)

      * mysqlbinlog now has the capability to back up a binary log in
        its original binary format. When invoked with the
        --read-from-remote-server and --raw options, mysqlbinlog
        connects to a server, requests the log files, and writes
        output files in the same format as the originals. See Section
        4.6.7.3, "Using mysqlbinlog to Back Up Binary Log Files."

      * mysqldump now has an --add-drop-trigger option which adds a
        DROP TRIGGER IF EXISTS statement before each dumped trigger
        definition. (Bug #34325, Bug #11747863)

     * mysqldump --xml now displays comments from column definitions.
        (Bug #13618, Bug #11745324)

     * A new SQL function, WEIGHT_STRING(), returns the weight string
        for an input string. The weight string represents the sorting
        and comparison value of the input string.

     * MySQL distributions now include auth_socket, a server-side
        authentication plugin that authenticates clients that connect
        from the local host through the Unix socket file. The plugin
        uses the SO_PEERCRED socket option to obtain information about
        the user running the client program (and thus can be built
        only on systems that support this option. For a connection to
        succeed, the plugin requires a match between the login name of
        the connecting client user and the MySQL user name presented
        by the client program. For more information, see Section
        5.5.6.1.4, "The Socket Peer-Credential Authentication Plugin."
        (Bug #59017, Bug #11765993)

      * Boolean system variables can be enabled at run time by setting
        them to the value ON or OFF, but previously this did not work
        at server startup. Now at startup such variables can be
        enabled by setting them to ON or TRUE, or disabled by setting
        them to OFF or FALSE. Any other nonnumeric variable is
        invalid. (Bug #46393, Bug #11755200)
        See also Bug #11754743, Bug #51631.

      * Previously, for queries that were aborted due to a sort
        problem, the server wrote the message Sort aborted to the
        error log. Now the server writes more information to provide a
        more specific message, such as:
         Sort aborted: Out of memory (Needed 24 bytes)
         Out of sort memory, consider increasing server sort buffer size
         Sort aborted: Out of sort memory, consider increasing
         server sort buffer size
         Sort aborted: Incorrect number of arguments for FUNCTION
         test.f1; expected 0, got 1
        In addition, if the server was started with --log-warnings=2,
        the server write information about the host, user, and query.
        (Bug #36022, Bug #11748358)

      * Previously, for queries that were aborted due to a sort
        problem or terminated with KILL in the middle of a sort, the
        server wrote the message Sort aborted to the error log. Now
        the server writes more information about the cause of the
        error. These causes include:
         Insufficient disk space in tmpdir prevented tmpfile from
           being created
         Insufficient memory for sort_buffer_size to be allocated
         Somebody ran KILL id in the middle of a filesort
         The server was shutdown while some queries were sorting
         A transaction got rolled back or aborted due to lock wait
           timeout or deadlock
         Unexpected errors, such as source table or even tmp table was
         corrupt processing of a subquery failed which was also sorting
        (Bug #30771, Bug #11747102)

      * The undocumented SHOW NEW MASTER statement has been removed.

      * MySQL distributions now include mysql_clear_password, a
        client-side authentication plugin that sends the password to
        the server without hashing or encryption. Although this is
        insecure, and thus appropriate precautions should be taken
        (such as using an SSL connection), the plugin is useful in
        conjunction with server-side plugins that must have access to
        the original password in clear text. For more information, see
        Section 5.5.6.1.3, "The Clear Text Client-Side Authentication
        Plugin."

      * A new plugin service, my_plugin_log_service, enables plugins
        to report errors and specify error messages. The server writes
        the messages to the error log. See Section 21.2.6, "MySQL
        Services for Plugins."

      * There is now a bind_address system variable containing the
        value of the --bind-address option. This enables the address
        to be accessed at runtime. (Bug #44355, Bug #11752999)

      * "Unknown table" error messages that included only the table
        name now include the database name as well. (Bug #34750, Bug
        #11747993)

      * Previously, EXPLAIN output for a large union truncated the
        UNION RESULT row at the end of the list as follows if the
        string became too large:
         <union1,2,3,4,...>
        To make it easier to understand the union boundaries,
        truncation now occurs in the middle of the string:
         <union1,2,3,...,9>
        (Bug #30597, Bug #11747073)

      * The OpenGIS specification defines functions that test the
        relationship between two geometry values. MySQL originally
        implemented these functions such that they used object
        bounding rectangles and returned the same result as the
        corresponding MBR-based functions. Corresponding versions are
        now available that use precise object shapes. These versions
        are named with an ST_ prefix. For example, Contains() uses
        object bounding rectangles, whereas ST_Contains() uses object
        shapes. For more information, see Section 11.17.5.4.2,
        "Functions That Test Spatial Relationships Between
        Geometries."
        There are also now ST_ aliases for existing spatial functions
        that were already exact. For example, ST_IsEmpty() is an alias
        for IsEmpty() (Bug #4249, Bug #11744883)

      * TO_BASE64() and FROM_BASE64() functions are now available to
        perform encoding to and from base-64 strings.

      * The Block Nested-Loop (BNL) Join algorithm previously used
        only for inner joins has been extended and can be employed for
        outer join operations, including nested outer joins. For more
        information, see Section 7.13.11, "Block Nested-Loop Joins."
        In conjunction with this work, there is a new system variable,
        optimizer_join_cache_level, that controls how join buffering
        is done.

      * A --bind-address option has been added to a number of MySQL
        client programs: mysql, mysqldump, mysqladmin, mysqlbinlog,
        mysqlcheck, mysqlimport, and mysqlshow. This is for use on a
        computer having multiple network interfaces, and enables you
        to choose which interface is used to connect to the MySQL
        server.


    Bugs fixed:
       The list of bugs fixed will follow in a separate mail, because
       of size restrictions on the mailing lists.

Hery Ramilison
MySQL/ORACLE Release Engineering Team


Thread
MySQL Community Server 5.6.2 has been releasedHery Ramilison11 Apr