オリジナル版：http://dev.mysql.com/doc/refman/5.0/en/news-5-0-21.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であるMySQL 5.0.21がリリースされました。コミュニティエディションは、http://dev.mysql.com/downloads/とミラーサイトのダウンロード・ページから、ソースコード及び多くのプラットフォームのためのバイナリで現在利用可能です。
すべてのミラーサイトが現在、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このバージョンを見つけることができない場合は、再度確認を行うか、あるいは別のダウンロード・サイトを選択してください。
これは最近の製品バージョンのバグ修正バージョンです。
このバージョンで解消された個々のバグに関するその他の詳細については、http://bugs.mysql.com/のバグデータベースを参照してください。
このセクションでは、その前の公式のMySQLリリース以来適用している、全ての変更とバグ修正を記録しています。使用するバージョンと特徴に関連した修正に関するより良質な個別の変更情報を受け取りたい場合は、MySQLネットワークにご登録下さい（商用のMySQL提供です。）より詳細については、http://www.mysql.com/network/advisors.htmlをご参照ください。
あなたのご意見をお待ちしています。
以下は、変更ログからのニュースです。
Functionality added or changed:
* Security enhancement: Added the global max_prepared_stmt_count
system variable to limit the total number of prepared
statements in the server. This limits the potential for
denial-of-service attacks based on causing the server to run
causing the server to run out of memory by preparing huge numbers
of statements. The current number of prepared statements is
available through the 'prepared_stmt_count' status variable.
(Bug#16365:http://bugs.mysql.com/16365)
* NDB Cluster: It is now possible to perform a partial start of
a cluster. That is, it is now possible to bring up the cluster
without running ndbd --initial on all configured data nodes
first. (Bug#18606:http://bugs.mysql.com/18606)
* NDB Cluster: It is now possible to install MySQL with Cluster
support to a non-default location and change the search path
for font description files using either the --basedir or
--character-sets-dir options. (Previously in MySQL 5.0, ndbd
searched only the default path for character sets.)
* In result set metadata, the MYSQL_FIELD.length value for BIT
columns now is reported in number of bits. For example, the
value for a BIT(9) column is 9. (Formerly, the value was
related to number of bytes.)
(Bug#13601:http://bugs.mysql.com/13601)
* The default for the innodb_thread_concurrency system variable
was changed to 8. (Bug#15868:http://bugs.mysql.com/15868)
Bugs fixed:
* Security bugfix: A malicious client, using specially crafted
invalid COM_TABLE_DUMP packets was able to trigger an exploitable
buffer overflow on the server. Thanks to Stefano Di Paola
<stefano.dipaola@stripped> for finding and reporting this bug.
* Security bugfix: A malicious client, using specially crafted
invalid login or COM_TABLE_DUMP packets was able to read
uninitialized memory, which potentially, though unlikely in MySQL,
could lead to an information disclosure. Thanks to Stefano Di Paola
<stefano.dipaola@stripped> for finding and reporting this bug.
* NDB Cluster: A simultaneous DROP TABLE and table update
operation utilising a table scan could trigger a node failure.
(Bug#18597:http://bugs.mysql.com/18597)
* Conversion of a number to a CHAR UNICODE string returned an
invalid result. (Bug#18691:http://bugs.mysql.com/18691)
* DELETE and UPDATE statements that used large NOT IN
(value_list) clauses could use large amounts of memory.
(Bug#15872:http://bugs.mysql.com/15872)
* Prevent recursive views caused by using RENAME TABLE on a view
after creating it. (Bug#14308:http://bugs.mysql.com/14308)
* A LOCK TABLES statement that failed could cause MyISAM not to
update table statistics properly, causing a subsequent CHECK
TABLE to report table corruption.
(Bug#18544:http://bugs.mysql.com/18544)
* For a reference to a non-existent stored function in a stored
routine that had a CONTINUE handler, the server continued as
though a useful result had been returned, possibly resulting
in a server crash. (Bug#18787:http://bugs.mysql.com/18787)
* InnoDB did not use a consistent read for CREATE ... SELECT
when innodb_locks_unsafe_for_binlog was set.
(Bug#18350:http://bugs.mysql.com/18350)
* InnoDB could read a delete mark from its system tables
incorrectly. (Bug#19217:http://bugs.mysql.com/19217)
* Corrected a syntax error in mysql-test-run.sh.
(Bug#19190:http://bugs.mysql.com/19190)
* A missing DBUG_RETURN() caused the server to emit a spurious
error message: missing DBUG_RETURN or DBUG_VOID_RETURN macro
in function "open_table".
(Bug#18964:http://bugs.mysql.com/18964)
* DROP DATABASE did not drop stored routines associated with the
database if the database name was longer than 21 characters.
(Bug#18344:http://bugs.mysql.com/18344)
* Avoid trying to include <asm/atomic.h> when it doesn't work in
C++ code. (Bug#13621:http://bugs.mysql.com/13621)
* Executing SELECT on a large table that had been compressed
within myisampack could cause a crash.
(Bug#17917:http://bugs.mysql.com/17917)
* NDB Cluster: When attempting to create an index on a BIT or
BLOB column, Error 743: Unsupported character set in table or
index was returned instead of Error 906: Unsupported attribute
type in index.
* Within stored routines, usernames were parsed incorrectly if
they were enclosed within quotes.
(Bug#13310:http://bugs.mysql.com/13310)
* Casting a string to DECIMAL worked, but casting a trimmed
string (using LTRIM() or RTRIM()) resulted in loss of decimal
digits. (Bug#17043:http://bugs.mysql.com/17043)
* NDB Cluster: On slow networks or CPUs, the management client
SHOW command could sometimes erroneously show all data nodes
as being master nodes belonging to nodegroup 0.
(Bug#15530:http://bugs.mysql.com/15530)
* If the second or third argument to BETWEEN was a constant
expression such as '2005-09-01 - INTERVAL 6 MONTH' and the
other two arguments were columns, BETWEEN was evaluated
incorrectly. (Bug#18618:http://bugs.mysql.com/18618)
* If the first argument to BETWEEN was a DATE or TIME column of
a view and the other arguments were constants, BETWEEN did not
perform conversion of the constants to the appropriate
temporary type, resulting in incorrect evaluation.
(Bug#16069:http://bugs.mysql.com/16069)
* Server and clients ignored the --sysconfdir option that was
passed to configure. (Bug#15069:http://bugs.mysql.com/15069)
* NDB Cluster: In a 2-node cluster with a node failure,
restarting the node with a low value for StartPartialTimeout
could cause the cluster to come up partitioned ("split-brain"
issue). (Bug#16447:http://bugs.mysql.com/16447)
A similar issue could occur when the cluster was first started
with a sufficiently low value for this parameter.
(Bug#18612:http://bugs.mysql.com/18612)
* NDB Cluster: On systems with multiple network interfaces, data
nodes would get "stuck" in startup phase 2 if the interface
connecting them to the management server was working on node
startup while the interface interconnecting the data nodes
experienced a temporary outage.
(Bug#15695:http://bugs.mysql.com/15695)
* NDB Cluster: Unused open handlers for tables in which the
metadata had changed were not properly closed. This could
result in stale results from Cluster tables following an ALTER
TABLE. (Bug#13228:http://bugs.mysql.com/13228)
* NDB Cluster: Uninitialised internal variables could lead to
unexpected results. (Bug#11033:http://bugs.mysql.com/11033,
Bug#11034:http://bugs.mysql.com/11034)
* For InnoDB tables, an expression of the form col_name BETWEEN
col_name2 - INTERVAL x DAY AND col_name2 + INTERVAL x DAY when
used in a join returned incorrect results.
(Bug#14360:http://bugs.mysql.com/14360)
* INSERT DELAYED into a view caused an infinite loop.
(Bug#13683:http://bugs.mysql.com/13683)
* Lettercase in database name qualifiers was not consistently
handled properly in queries when lower_case_table_names was
set to 1. (Bug#15917:http://bugs.mysql.com/15917)
* The optimizer could cause a server crash or use a non-optimal
subset of indexes when evaluating whether to use Index
Merge/Intersection variant of index_merge optimization.
(Bug#19021:http://bugs.mysql.com/19021)
* The presence of multiple equalities in a condition after
reading a constant table could cause the optimizer not to use
an index. This resulted in certain queries being much slower
than in MySQL 4.1. (Bug#16504:http://bugs.mysql.com/16504)
* A recent change caused the mysql client not to display NULL
values correctly and to display numeric columns left-justified
rather than right-justified. The problems have been corrected.
(Bug#18265:http://bugs.mysql.com/18265)
* mysql_reconnect() sent a SET NAMES statement to the server,
even for pre-4.1 servers that do not understand the statement.
(Bug#18830:http://bugs.mysql.com/18830)
* COUNT(*) on a MyISAM table could return different results for
the base table and a view on the base table.
(Bug#18237:http://bugs.mysql.com/18237)
* DELETE with LEFT JOIN for InnoDB tables could crash the server
if innodb_locks_unsafe_for_binlog was enabled.
(Bug#15650:http://bugs.mysql.com/15650)
* InnoDB failure to release an adaptive hash index latch could
cause a server crash if the query cache was enabled.
(Bug#15758:http://bugs.mysql.com/15758)
* For mysql.server, if the basedir option was specified after
datadir in an option file, the setting for datadir was ignored
and assumed to be located under basedir.
(Bug#16240:http://bugs.mysql.com/16240)
* The euro sign () was not stored correctly in columns using
the latin1_german1_ci or latin1_general_ci collation.
(Bug#18321:http://bugs.mysql.com/18321)
* EXTRACT(QUARTER FROM date) returned unexpected results.
(Bug#18100:http://bugs.mysql.com/18100)
* TRUNCATE did not reset the AUTO_INCREMENT counter for MyISAM
tables when issued inside a stored procedure.
(Bug#14945:http://bugs.mysql.com/14945)
Note: This bug did not affect InnoDB tables. Also, TRUNCATE
does not reset the AUTO_INCREMENT counter for NDBCluster
tables regardless of when it is called (see
Bug#18864:http://bugs.mysql.com/18864).
* The server was always built as though
--with-extra-charsets=complex had been specified.
(Bug#12076:http://bugs.mysql.com/12076)
* A query using WHERE (column_1, column_2) IN ((value_1,
value_2)[, (..., ...), ...]) would return incorrect results.
(Bug#16248:http://bugs.mysql.com/16248)
* Queries of the form SELECT DISTINCT timestamp_column WHERE
date_function(timestamp_col) = constant did not return all
matching rows. (Bug#16710:http://bugs.mysql.com/16710)
* When running a query that contained a GROUP_CONCAT( SELECT
GROUP_CONCAT(...) ), the result was NULL except in the ROLLUP
part of the result, if there was one.
(Bug#15560:http://bugs.mysql.com/15560)
* For tables created in a MySQL 4.1 installation upgraded to
MySQL 5.0 and up, multiple-table updates could update only the
first matching row. (Bug#16281:http://bugs.mysql.com/16281)
* NDB Cluster: When multiple node restarts were attempted
without allowing each restart to complete, the error message
returned was Array index out of bounds rather than Too many
crashed replicas. (Bug#18349:http://bugs.mysql.com/18349)
* CAST (double AS SIGNED INT) for large double values outside the
signed integer range truncates the result to be within range,
but the result sometimes had the wrong sign, and no warning
was generated. (Bug#15098:http://bugs.mysql.com/15098)
* Updating a field value when also requesting a lock with
GET_LOCK() would cause slave servers in a replication
environment to terminate.
(Bug#17284:http://bugs.mysql.com/17284)