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From:Hery Ramilison Date:September 29 2012 3:59pm
Subject:MySQL Community Server 5.5.28 has been released
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Dear MySQL users,

MySQL 5.5.28 is a new version of the 5.5 production release of the
world's most popular open source database. MySQL 5.5.28 is recommended
for use on production systems.

MySQL 5.5 includes several high-impact enhancements to improve the
performance and scalability of the MySQL Database, taking advantage of
the latest multi-CPU and multi-core hardware and operating systems. In
addition, with release 5.5, InnoDB is now the default storage engine for
the MySQL Database, delivering ACID transactions, referential integrity
and crash recovery by default.

MySQL 5.5 also provides a number of additional enhancements including:

     - Significantly improved performance on Windows, with various
       Windows specific features and improvements
     - Higher availability, with new semi-synchronous replication and
       Replication Heart Beat
     - Improved usability, with Improved index and table partitioning,
       SIGNAL/RESIGNAL support and enhanced diagnostics, including a new
       Performance Schema monitoring capability.

For a more complete look at what's new in MySQL 5.5, please see the
following resources:

MySQL 5.5 is GA, Interview with Tomas Ulin:


Whitepaper: What's New in MySQL 5.5:

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.

For information on installing MySQL 5.5.28 on new servers, please see
the MySQL installation documentation at

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

MySQL Database 5.5.28 is available in source and binary form for a
number of platforms from our download pages at:

The following section lists the changes in the MySQL source code since
the previous released version of MySQL 5.5. It may also be viewed
online at:


Changes in MySQL 5.5.28 (2012-September-28)

Functionality Added or Changed

   * The internal interface of the Thread Pool plugin has changed.
     Old versions of the plugin will work with current versions of
     the server, but versions of the server older than 5.5.28 will
     not work with current versions of the plugin.

Bugs Fixed

   * InnoDB: Certain information_schema tables originally
     introduced in MySQL 5.6 are now also available in MySQL 5.5
     INNODB_BUFFER_POOL_STATS. (Bug #13113026)

   * InnoDB: When a SELECT ... FOR UPDATE, UPDATE, or other SQL
     statement scanned rows in an InnoDB table using a < or <=
     operator in a WHERE clause, the next row after the affected
     range could also be locked. This issue could cause a lock wait
     timeout for a row that was not expected to be locked. The
     issue occurred under various isolation levels, such as READ
     COMMITTED and REPEATABLE READ. (Bug #11765218)

   * Partitioning: For tables using PARTITION BY HASH or PARTITION
     BY KEY, when the partition pruning mechanism encountered a
     multi-range list or inequality using a column from the
     partitioning key, it continued with the next partitioning
     column and tried to use it for pruning, even if the previous
     column could not be used. This caused partitions which
     possibly matched one or more of the previous partitioning
     columns to be pruned away, leaving partitions that matched
     only the last column of the partitioning key.
     This issue was triggered when both of the following conditions
     were met:

       1. The columns making up the table's partitioning key were
          used in the same order as in the partitioning key
          definition by a SELECT statement's WHERE clause as in the
          column definitions;

       2. The WHERE condition used with the last column of the
          partitioning key was satisfied only by a single value,
          while the condition testing some previous column from the
          partitioning key was satisfied by a range of values.
     An example of a statement creating a partitioned table and a
     query against this for which the issue described above
     occurred is shown here:
       CREATE TABLE t1 (
       c1 INT,
       c2 INT,
       PRIMARY KEY(c2, c1)
       ) PARTITION BY KEY()  # Use primary key as partitioning key
       PARTITIONS 2;

       SELECT * FROM t1 WHERE c2 = 2 AND c1 <> 2;
     This issue is resolved by ensuring that partition pruning
     skips any remaining partitioning key columns once a partition
     key column that cannot be used in pruning is encountered. (Bug

   * Partitioning: The buffer for the row currently read from each
     partition used for sorted reads was allocated on open and
     freed only when the partitioning handler was closed or
     destroyed. For SELECT statements on tables with many
     partitions and large rows, this could cause the server to use
     excessive amounts of memory.
     This issue has been addressed by allocating buffers for reads
     from partitioned tables only when they are needed and freeing
     them immediately once they are no longer needed. As part of
     this fix, memory is now allocated for reading from rows only
     in partitions that have not been pruned (see Partition Pruning
     tml)). (Bug #13025132)
     References: See also Bug #11764622, Bug #14537277.

   * Replication: On 64-bit Windows platforms, values greater than
     4G for the max_binlog_cache_size and
     max_binlog_stmt_cache_size system variables were truncated to
     4G. This caused LOAD DATA INFILE to fail when trying to load a
     file larger than 4G in size, even when max_binlog_cache_size
     was set to a value greater than this. (Bug #13961678)

   * Replication: In master-master replication with
     --log-slave-updates enabled, setting a user variable and then
     performing inserts using this variable caused the
     Exec_master_log_position column in the output of SHOW SLAVE
     STATUS not to be updated. (Bug #13596613)

   * The RPM spec file now also runs the test suite on the new
     binaries, before packaging them. (Bug #14318456)

   * The libmysqlclient_r client library exported symbols from
     yaSSL that conflict with OpenSSL. If a program linked against
     that library and libcurl, it could crash with a segmentation
     fault. (Bug #14068244)

   * The argument for LIMIT must be an integer, but if the argument
     was given by a placeholder in a prepared statement, the server
     did not reject noninteger values such as '5'. (Bug #13868860)

   * The Thread Pool plugin did not respect the wait_timeout
     timeout for client sessions. (Bug #13699303)

   * CHECK TABLE and REPAIR TABLE could crash if a key definition
     differed in the .frm and .MYI files of a MyISAM table. Now the
     server produces an error. (Bug #13555854)

   * A query for a FEDERATED table could return incorrect results
     when the underlying table had a compound index on two columns
     and the query included an AND condition on the columns. (Bug

   * mysqlhotcopy failed for databases containing views. (Bug
     #62472, Bug #13006947, Bug #12992993)

   * The argument to the --ssl-key option was not verified to exist
     and be a valid key. The resulting connection used SSL, but the
     key was not used. (Bug #62743, Bug #13115401)

   * Adding a LIMIT clause to a query containing GROUP BY and ORDER
     BY could cause the optimizer to choose an incorrect index for
     processing the query, and return more rows than required. (Bug
     #54599, Bug #11762052)

   * mysqlbinlog did not accept input on the standard input when
     the standard input was a pipe. (Bug #49336, Bug #11757312)

On behalf of the MySQL/ORACLE Build Team

Hery Ramilison

MySQL Community Server 5.5.28 has been releasedHery Ramilison29 Sep