MySQL Community Server 5.5.40 has been released

[Murthy Narkedimilli]

Dear MySQL users,

MySQL Server 5.5.40 is a new version of the 5.5 production release
of the world's most popular open source database. MySQL 5.5.40 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 Heartbeat
- 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://www.mysql.com/why-mysql/white-papers/whats-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.
http://mysql.com/products/enterprise/

For information on installing MySQL 5.5.40 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 5.5.40 is available in source and binary form for a
number of platforms from our download pages at:
http://dev.mysql.com/downloads/mysql/

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/relnotes/mysql/5.5/en/news-5-5-40.html

Enjoy!


Changes in MySQL 5.5.40 (2014-09-22)

Bugs Fixed

* InnoDB: An ALTER TABLE ... ADD FOREIGN KEY operation could
cause a serious error. (Bug #19471516, Bug #73650)

* InnoDB: With a transaction isolation level less than or equal
to READ COMMITTED, gap locks were not taken when scanning a
unique secondary index to check for duplicates. As a result,
duplicate check logic failed allowing duplicate key values in
the unique secondary index. (Bug #19140907)
References: This bug is a regression of Bug #16133801.

* InnoDB: During recovery, a segmentation fault would occur when
marking a table as corrupt. (Bug #18942294)

* yaSSL client code did not validate the encryption size or
session ID length, which could cause the client to exit. (Bug
#19463277, Bug #19463565)

* MySQL installation from RPM packages could fail if Postfix had
been installed using yum. (Bug #19392127)

* yaSSL could fail preauthorization if the client supplied
inaccurate buffer lengths. (Bug #19370676, Bug #19355577)

* Competition between threads could lead to timeout failure
trying to rotate the audit log file. (Bug #19184973)

* On Linux (OEL6), if Sun DTrace was installed, the MySQL build
failed. (Bug #19149091)

* LPAD() and RPAD() could cause a server exit if the pad string
argument was not well formed. (Bug #18935421)

* The optimizer could create a zero-length column for a
temporary table, causing a server exit. (Bug #18928848)

* MOD for very small decimal right-hand arguments could cause a
server exit. (Bug #18469276)

* The client library now includes a call to
X509_verify_cert_error_string() in the SSL certificate
verification code, to be more robust in detecting invalid
certificates. (Bug #18384260)

* The thread_concurrency system variable is deprecated, but no
warning resulted from setting it at server startup. (Bug
#17873011)

* Sending a SIGQUIT or SIGINT signal to mysql could result in a
glibc double free or corruption error. (Bug #17297324)

* LIKE matches failed for code points of HALF WIDTH KATAKANA in
the sjis and cp932 character sets. (Bug #47641, Bug #11755818)

* On EL7, installation of MySQL from RPM packages could fail if
postfix had previously been installed using yum. (Bug #73507,
Bug #19392051, Bug #19392149)

* mysql_upgrade could fail if the mysql.user table contained
multiple accounts with the same user name and host name where
the host name differed in lettercase. This is still not
permitted, but now mysql_upgrade prints a more informative
error message to indicate the nature of the problem:
ERROR 1644 (45000): Multiple accounts exist for user_name, host_name
that differ only in Host lettercase; remove all except one of them
(Bug #72066, Bug #18415196)

* If the general query log or slow query log file was set to a
FIFO or socket file, and the file reader went away, the server
stopped executing statements. Now the server detects such
files, logs an error message, and continues with the
appropriate log disabled. (Bug #67088, Bug #14757009)

On behalf of Oracle/MySQL RE Team,
Murthy Narkedimilli