Dear MySQL users,

MySQL 5.5.16 is a new version of the 5.5 production release of the
world's most popular open source database. MySQL 5.5.16 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:

http://dev.mysql.com/tech-resources/interviews/thomas-ulin-mysql-55.html

Documentation:

http://dev.mysql.com/doc/refman/5.5/en/mysql-nutshell.html

Whitepaper: What's New in MySQL 5.5:

http://dev.mysql.com/why-mysql/white-papers/mysql-wp-whatsnew-mysql-55.php

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/

For information on installing MySQL 5.5.16 on new servers, please see
the MySQL installation documentation at

http://dev.mysql.com/doc/refman/5.5/en/installing.html

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

http://dev.mysql.com/doc/refman/5.5/en/upgrading.html

MySQL Database 5.5 is available in source and binary form for a number
of platforms from 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 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:

http://dev.mysql.com/doc/refman/5.5/en/news-5-5-16.html

Enjoy!


Functionality Added or Changed

* Important Change: Replication: The RESET SLAVE statement has
been extended with an ALL keyword. In addition to deleting the
master.info, relay-log.info, and all relay log files, RESET
SLAVE ALL also clears all connection information otherwise
held in memory following execution of RESET SLAVE. (Bug
#11809016)

* A new utility, mysql_plugin, enables MySQL administrators to
manage which plugins a MySQL server loads. It provides an
alternative to manually specifying the --plugin-load option at
server startup or using the INSTALL PLUGIN and UNINSTALL
PLUGIN statements at runtime. See Section 4.4.5, "mysql_plugin
--- Configure MySQL Server Plugins."

Bugs Fixed

* InnoDB Storage Engine: The "random read-ahead
(http://dev.mysql.com/doc/innodb/1.1/en/glossary.html#glos_rea
d_ahead)" feature that was removed from the InnoDB Plugin is
now available again. Because it is only helpful for certain
workloads, it is turned off by default. To turn it on, enable
the innodb_random_read_ahead configuration option. Because
this feature can improve performance in some cases and reduce
performance in others, before relying on this setting,
benchmark both with and without the setting enabled. (Bug
#12356373)

* The metadata locking subsystem added too much overhead for
INFORMATION_SCHEMA queries that were processed by opening only
.frm or .TRG files and had to scan many tables. For example,
SELECT COUNT(*) FROM INFORMATION_SCHEMA.TRIGGERS was affected.
(Bug #12828477)

* Compilation failed on Mac OS X 10.7 (Lion) with a warning:
Implicit declaration of function 'pthread_init' (Bug
#12779790)

* With profiling disabled or not compiled in,
set_thd_proc_info() unnecessarily checked file name lengths.
(Bug #12756017)

* A DBUG_ASSERT added by Bug #11792200 was overly aggressive in
raising assertions. (Bug #12537160)

* CHECK TABLE and REPAIR TABLE failed to find problems with
MERGE tables that had underlying tables missing or with the
wrong storage engine. Issues were reported only for the first
underlying table. (Bug #11754210)

* Replication: Processing of corrupted table map events could
cause the server to crash. This was especially likely if the
events mapped different tables to the same identifier, such as
could happen due to Bug#56226.
Now, before applying a table map event, the server checks
whether the table has already been mapped with different
settings, and if so, an error is raised and the slave SQL
thread stops. If it has been mapped with the same settings, or
if the table is set to be ignored by filtering rules, there is
no change in behavior: the event is skipped and IDs are not
checked. (Bug #44360, Bug #11753004)
See also Bug #11763509.

* For a lower_case_table_names value of 1 or 2 and a database
having a mixed-case name, calling a stored function using a
fully qualified name including the database name failed. (Bug
#60347, Bug #11840395)

* Previously, Performance Schema table columns that held byte
counts were BIGINT UNSIGNED. These were changed to BIGINT
(signed). This makes it easier to perform calculations that
compute differences between columns. (Bug #59631, Bug
#11766504)

* The embedded server crashed when argc = 0. (Bug #57931, Bug
#12561297)

* The mysql_affected_rows() C API function returned 3 (instead
of 2) for INSERT ... ON DUPLICATE KEY UPDATE statements where
there was a duplicated key value. (Bug #46675, Bug #11754979)

* Upgrades using an RPM package recreated the test database,
which is undesirable when the DBA had removed it. (Bug #45415,
Bug #11753896)


--
Daniel Fischer, Release Staff Engineer, MySQL RE 49,8.37 +491704447185
ORACLE Deutschland B.V. & Co. KG, Riesstr. 25, 80992 M=FCnchen - HRA MUC 95603
Komplementaer: ORACLE Deutschl. Verw. B.V., Rijnzathe 6, 3454PV De Meern, NL
Geschaeftsfuehrer: Juergen Kunz, Marcel van de Molen, Alexander van der Ven





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