Made internal representation of TIMESTAMP values in InnoDB in 4.1 to be the same as in 4.0. This difference resulted in incorrect datetime values in TIMESTAMP columns in InnoDB tables after an upgrade from 4.0 to 4.1. Warning: extra steps during upgrade required! Unfortunately this means that if you are upgrading from 4.1.x, where x <= 3, to 4.1.4 you should use mysqldump for saving and then restoring your InnoDB tables with TIMESTAMP columns. (Bug#4492)

Made the MySQL server ignore SIGHUP and SIGQUIT on Mac OS X 10.3. This is needed because under this OS, the MySQL server receives lots of these signals. (Bug#2030)

Support of usage of column aliases qualified by table name or alias in ORDER BY and GROUP BY was dropped. For example the following query SELECT a AS b FROM t1 ORDER BY t1.b is not allowed. One should use SELECT a AS b FROM t1 ORDER BY t1.a or SELECT a AS b FROM t1 ORDER BY b instead. This was non-standard (since aliases are defined on query level not on table level) and caused problems with some queries.

Corrected the name of the Mac OS X StartupItem script (it must match the name of the subdirectory, which was renamed to MySQLCOM in MySQL 4.1.2). Thanks to Bryan McCormack for reporting this.

Added Latin language collations for the ucs2 and utf8 Unicode character sets. These are called ucs2_roman_ci and utf8_roman_ci.

Added --start-datetime, --stop-datetime, --start-position, and --stop-position options to mysqlbinlog. These make point-in-time recovery easier.

Added the CSV storage engine.

Killing a CHECK TABLE statement does not result in the table being marked as “corrupted” any more; the table remains as if CHECK TABLE had not even started. See Section 12.5.5.3, “KILL Syntax”.

The mysqld-opt Windows server was renamed to mysqld. This completes the Windows server renaming begun in MySQL 4.1.2. See Section 2.3.8, “Selecting a MySQL Server Type”.

Fixed a bug that caused libmysql to crash when attempting to fetch a value of MEDIUMINT column. (Bug#5126)

Fixed that disable-local-infile option had no effect if client read it from a configuration file using mysql_options(...,MYSQL_READ_DEFAULT,...). (Bug#5073)

Fixed that SET GLOBAL SYNC_BINLOG did not work on some platforms (Mac OS X). (Bug#5064)

Fixed that mysql-test-run failed on the rpl_trunc_binlog test if running test from the installed (the target of 'make install') directory. (Bug#5050)

mysql_options(...,MYSQL_OPT_LOCAL_INFILE,...) failed to disable LOAD DATA LOCAL INFILE. (Bug#5038)

Fixed a bug that caused the MySQL server to crash when attempting to execute a prepared statement with SELECT ... INTO @var for a second time. (Bug#5034)

The counter for an AUTO_INCREMENT column was not reset by TRUNCATE TABLE if the table was a temporary one. (Bug#5033)

Fixed a bug that omitted the .err extension of the error log file (--log-error) when the hostname contained a domain name. The domain name is now replaced by the extension. (Bug#4997)

A CREATE TABLE ... TYPE=HEAP ... AS SELECT... statement caused the replication slave to stop. (Bug#4971)

FLUSH TABLES WITH READ LOCK now blocks COMMIT statements if the server is running with binary logging enabled; this ensures that the binary log position is trustable when doing a full backup of tables and the binary log. (Bug#4953)

Attempting to execute for a second time a prepared statement with NOT in an WHERE or ON clause caused the server to crash. (Bug#4912)

Fixed a crash in myisamchk. (Bug#4901)

KILLing a connection while it was performing START SLAVE caused the server to crash. (Bug#4827)

Prohibited resolving of table fields in inner queries if fields do not take part in grouping for queries with grouping (inside aggregate function arguments, all table fields are still allowed). (Bug#4814)

Fixed an unlikely deadlock which could happen when using KILL. (Bug#4810)

NATURAL JOIN where the joined tables had no common column caused the server to hang. (Bug#4807)

MATCH ... AGAINST now works in a subquery. (Bug#4769)

Support for %T, %r, %V, %v and %X, %x format specifiers was added to STR_TO_DATE() function. (Bug#4756)

Fixed that mysql-test-run failed on the grant_cache test when run as Unix user 'root'. (Bug#4678)

Fixed a crash after SLAVE STOP if the IO replication thread is in the state Waiting to reconnect after a failed master event read. (Bug#4629)

Fixed that when a multiple-table DROP TABLE failed to drop a table on the master server, the error code was not written to the binary log. (Bug#4553)

If CREATE TEMPORARY TABLE t SELECT failed while loading the data, the temporary table was not dropped. (Bug#4551)

Fixed a bug which caused server crash if one used the CONVERT_TZ() function with time zone described in database as parameter and this time zone was not used before. (Bug#4508)

mysqlbinlog --read-from-remote-server sometimes could not accept 2 binary logs in a single invocation. (Bug#4507)

mysqlbinlog --position --read-from-remote-server had incorrect output for # at log_pos. (Bug#4506)

Fixed a crash caused by UNHEX(NULL). (Bug#4441)

Execution IN subqueries that use compound indexes was better optimized. (Bug#4435)

Fixed an assertion failure when reading the grant tables (Bug#4407)

When the slave SQL thread was replicating a LOAD DATA INFILE statement, it didn't show the statement in the output of SHOW PROCESSLIST. (Bug#4326)

An error was reported when a column from an ORDER BY clause was present in two tables participating in a SELECT, even if the second instance of column in select list was renamed. (For example, SELECT t1.a AS c FROM t1, t2 ORDER BY a produced an error if both t1 and t2 tables contain column a).

Now MySQL does not prefer columns, mentioned in a select list but renamed, over columns from other tables participating in a FROM clause when it resolves the ORDER BY clause. (Bug#4302)

mysql_fix_privilege_tables did not handle the --password=password_val option correctly. (Bug#4240, Bug#4543)

Fixed an old bug in concurrent accesses to MERGE tables (even one MERGE table and MyISAM tables), that could have resulted in a crash or hang of the server. (Bug#2408)