オリジナル版：http://dev.mysql.com/doc/refman/5.1/en/news-5-1-55.html
最も普及しているオープンソースデータベース管理システムの新バージョンMySQL Community Server 5.1.55がリリースされました。MySQL 5.1.55は、プロダクションシステムでの使用をお勧めします。
MySQL 5.1の新機能の概要については、以下を参照してください。
http://dev.mysql.com/doc/refman/5.1/en/mysql-nutshell.html
新たなサーバにMySQL 5.1.55をインストール、または以前のMySQLリリースからMySQL 5.1.55にアップグレードする際の情報については、以下を参照してください。
http://dev.mysql.com/doc/refman/5.1/en/installing.html
下記のダウンロードページから、MySQLサーバのソースコード及び多数のプラットフォーム用バイナリが入手可能です
http://dev.mysql.com/downloads/
現時点ですべてのミラーサイトが最新であるとは限らないことに注意してください。
あるミラーサイトで本バージョンを見つけることができない場合は、後日再確認を行うか、別のダウンロード・サイトを選択してください。
フィードバック、バグレポート、バグ修正、パッチ等の情報をお待ちしておりますので、以下のページをご利用ください。
http://forge.mysql.com/wiki/Contributing
MySQL 5.1に関するオープンな問題の情報については、以下のエラッタリストを参照してください。
http://dev.mysql.com/doc/refman/5.1/en/open-bugs.html
以下のセクションは、MySQL5.1の前リリース以降のMySQLソースコードの変更を記載しています。これはオンラインでも閲覧可能です：
http://dev.mysql.com/doc/refman/5.1/en/news-5-1-55.html
以下は、追加または変更された機能です。
Changes in MySQL 5.1.55 (7 February, 2011)
Functionality added or changed:
* The time zone tables available at
http://dev.mysql.com/downloads/timezones.html have been
updated. These tables can be used on systems such as Windows
or HP-UX that do not include zoneinfo files.
(Bug#40230: http://bugs.mysql.com/bug.php?id=40230)
Bugs fixed:
* Incompatible Change: When auto_increment_increment is greater
than one, values generated by a bulk insert that reaches the
maximum column value could wrap around rather producing an
overflow error.
As a consequence of the fix, it is no longer possible for an
auto-generated value to be equal to the maximum BIGINT
UNSIGNED value. It is still possible to store that value
manually, if the column can accept it.
(Bug#39828: http://bugs.mysql.com/bug.php?id=39828)
* Important Change: Partitioning: Date and time functions used
as partitioning functions now have the types of their operands
checked; use of a value of the wrong type is now disallowed in
such cases. In addition, EXTRACT(WEEK FROM col), where col is
a DATE or DATETIME column, is now disallowed altogether
because its return value depends on the value of the
default_week_format system variable.
(Bug#54483: http://bugs.mysql.com/bug.php?id=54483)
See also Bug#57071: http://bugs.mysql.com/bug.php?id=57071.
* InnoDB Storage Engine: A compilation problem affected the
InnoDB source code on NetBSD/sparc64.
(Bug#59327: http://bugs.mysql.com/bug.php?id=59327)
See also Bug#53916: http://bugs.mysql.com/bug.php?id=53916.
* InnoDB Storage Engine: In InnoDB status output, the value for
I/O sum[] could be incorrect, displayed as a very large
number. (Bug#57600: http://bugs.mysql.com/bug.php?id=57600)
* InnoDB Storage Engine: It was not possible to query the
information_schema.innodb_trx table while other connections
were running queries involving BLOB types.
(Bug#55397: http://bugs.mysql.com/bug.php?id=55397)
* InnoDB Storage Engine: The OPTIMIZE TABLE statement would
reset the auto-increment counter for an InnoDB table. Now the
auto-increment value is preserved across this operation.
(Bug#18274: http://bugs.mysql.com/bug.php?id=18274)
* Partitioning: Failed ALTER TABLE ... PARTITION statements
could cause memory leaks.
(Bug#56380: http://bugs.mysql.com/bug.php?id=56380)
See also Bug#46949: http://bugs.mysql.com/bug.php?id=46949,
Bug#56996: http://bugs.mysql.com/bug.php?id=56996.
* Replication: When closing a session that used temporary
tables, binary logging could sometimes fail with a spurious
Failed to write the DROP statement for temporary tables to
binary log.
(Bug#57288: http://bugs.mysql.com/bug.php?id=57288)
* Replication: By default, a value is generated for an
AUTO_INCREMENT column by inserting either NULL or 0 into the
column. Setting the NO_AUTO_VALUE_ON_ZERO server SQL mode
suppresses this behavior for 0, so that it occurs only when
NULL is inserted into the column.
This behavior is also followed on a replication slave (by the
slave SQL thread) when applying events that have been logged
on the master using the statement-based format. However, when
applying events that had been logged using the row-based
format, NO_AUTO_VALUE_ON_ZERO was ignored, which could lead to
an assertion.
To fix this issue, the value of an AUTO_INCREMENT column is no
longer generated when applying an event that was logged using
the row-based row format, as this value is already contained
in the changes applied on the slave.
(Bug#56662: http://bugs.mysql.com/bug.php?id=56662)
* Replication: The BINLOG statement modified the values of
session variables, which could lead to problems with
operations such a point-in-time recovery. One such case
occurred when replaying a row-based binary log which relied on
setting foreign_key_checks = OFF on the session level in order
to create and populate a set of InnoDB tables having foreign
key constraints.
(Bug#54903: http://bugs.mysql.com/bug.php?id=54903)
* Replication: mysqlbinlog printed USE statements to its output
only when the default database changed between events. To
illustrate how this could cause problems, suppose that a user
issued the following sequence of statements:
CREATE DATABASE mydb;
USE mydb;
CREATE TABLE mytable (column_definitions);
DROP DATABASE mydb;
CREATE DATABASE mydb;
USE mydb;
CREATE TABLE mytable (column_definitions);
When played back using mysqlbinlog, the second CREATE TABLE
statement failed with Error: No Database Selected because the
second USE statement was not played back, due to the fact that
a database other than mydb was never selected.
This fix insures that mysqlbinlog outputs a USE statement
whenever it reads one from the binary log.
(Bug#50914: http://bugs.mysql.com/bug.php?id=50914)
* Replication: Previously, when a statement failed with a
different error on the slave than on the master, the slave SQL
thread displayed a message containing:
+ The error message for the master error code
+ The master error code
+ The error message for the slaves error code
+ The slave error code
However, the slave has no information with which to fill in
any print format specifiers for the master message, so it
actually displayed the message format string. To make it
clearer that the slave is not displaying the actual message as
it appears on the master, the slave now indicates that the
master part of the output is the message format, not the
actual message. For example, previously the slave displayed
information like this:
Error: "Query caused different errors on master and slave.
Error on master: 'Duplicate entry '%-.192s' for key %d'
(1062), Error on slave: 'no error' (0). Default database:
'test'. Query: 'insert into t1 values(1),(2)'" (expected
different error codes on master and slave)
Now the slave displays this:
Error: "Query caused different errors on master and slave.
Error on master: message format='Duplicate entry '%-.192s' for
key %d' error code=1062 ; Error on slave: actual message='no
error', error code=0. Default database: 'test'. Query: 'insert
into t1 values(1),(2)'" (expected different error codes on
master and slave)
(Bug#46697: http://bugs.mysql.com/bug.php?id=46697)
* Replication: When an error occurred in the generation of the
name for a new binary log file, the error was logged but not
shown to the user.
(Bug#46166: http://bugs.mysql.com/bug.php?id=46166)
See also Bug#37148: http://bugs.mysql.com/bug.php?id=37148,
Bug#40611: http://bugs.mysql.com/bug.php?id=40611,
Bug#43929: http://bugs.mysql.com/bug.php?id=43929,
Bug#51019: http://bugs.mysql.com/bug.php?id=51019.
* MIN(year_col) could return an incorrect result in some cases.
(Bug#59211: http://bugs.mysql.com/bug.php?id=59211)
* If max_allowed_packet was set larger than 16MB, the server
failed to reject too-large packets with "Packet too large"
errors. (Bug#58887: http://bugs.mysql.com/bug.php?id=58887)
* Issuing EXPLAIN EXTENDED for a query that would use condition
pushdown could cause mysqld to crash.
(Bug#58553: http://bugs.mysql.com/bug.php?id=58553)
* EXPLAIN could crash for queries that used GROUP_CONCAT().
(Bug#58396: http://bugs.mysql.com/bug.php?id=58396)
* Configuration with maintainer mode enabled resulted in errors
when compiling with icc.
(Bug#57991: http://bugs.mysql.com/bug.php?id=57991,
Bug#58871: http://bugs.mysql.com/bug.php?id=58871)
* Unnecessary subquery evaluation in contexts such as statement
preparation or view creation could cause a server crash.
(Bug#57703: http://bugs.mysql.com/bug.php?id=57703)
* View creation could produce Valgrind warnings.
(Bug#57352: http://bugs.mysql.com/bug.php?id=57352)
* NULL geometry values could cause a crash in
Item_func_spatial_collection::fix_length_and_dec.
(Bug#57321: http://bugs.mysql.com/bug.php?id=57321)
* The cp1251 character set did not properly support the Euro
sign (0x88). For example, converting a string containing this
character to utf8 resulted in '?' rather than the utf8 Euro
sign. (Bug#56639: http://bugs.mysql.com/bug.php?id=56639)
* Some unsigned system variables could be displayed with
negative values.
(Bug#55794: http://bugs.mysql.com/bug.php?id=55794)
* CREATE DATABASE and DROP DATABASE caused mysql --one-database
to lose track of the statement-filtering context.
(Bug#54899: http://bugs.mysql.com/bug.php?id=54899)
* An assertion could be raised during concurrent execution of
DROP DATABASE and REPAIR TABLE if the drop deleted a table's
.TMD file at the same time the repair tried to read details
from the old file that was just removed.
A problem could also occur when DROP TABLE tried to remove all
files belonging to a table at the same time REPAIR TABLE had
just deleted the table's .TMD file.
(Bug#54486: http://bugs.mysql.com/bug.php?id=54486)
* When mysqld printed crash dump information, it incorrectly
indicated that some valid pointers were invalid.
(Bug#51817: http://bugs.mysql.com/bug.php?id=51817)
* On FreeBSD, if mysqld was killed with a SIGHUP signal, it
could corrupt InnoDB .ibd files.
(Bug#51023: http://bugs.mysql.com/bug.php?id=51023)
* An assertion could be raised if -1 was inserted into an
AUTO_INCREMENT column by a statement writing more than one
row. (Bug#50619: http://bugs.mysql.com/bug.php?id=50619)
* If a client supplied a user name longer than the maximum 16
characters allowed for names stored in the MySQL grant tables,
all characters were being considered significant.
Historically, only the first 16 characters were used to check
for a match; this behavior was restored.
(Bug#49752: http://bugs.mysql.com/bug.php?id=49752)
* The my_seek() and my_tell() functions ignored the MY_WME flag
when they returned an error, which could cause client programs
to hang. (Bug#48451: http://bugs.mysql.com/bug.php?id=48451)
* During assignment of values to system variables, legality
checks on the value range occurred too late, preventing proper
error checking.
(Bug#43233: http://bugs.mysql.com/bug.php?id=43233)
* On Solaris, time-related functions such as NOW() or SYSDATE()
could return a constant value.
(Bug#42054: http://bugs.mysql.com/bug.php?id=42054)
* If the remote server for a FEDERATED table could not be
accessed, queries for the INFORMATION_SCHEMA.TABLES table
failed. (Bug#35333: http://bugs.mysql.com/bug.php?id=35333)