We are now working actively on MySQL 4.1 and 5.0, and will provide only critical bug fixes for MySQL 4.0 and MySQL 3.23. We update this section as we add new features, so that everybody can follow the development.

Our TODO section contains what further plans we have for 4.1 & 5.0. See section 1.6 MySQL and the Future (The TODO).

Note that we tend to update the manual at the same time we make changes to MySQL. If you find a version listed here that you can't find on the MySQL download page (http://www.mysql.com/downloads/), this means that the version has not yet been released!

The date mentioned with a release version is the date of the last BitKeeper ChangeSet that this particular release has been based on, not the date when the packages have been made available. The binaries are usually made available a few days after the date of the tagged ChangeSet - building and testing all packages takes some time.

C.1 Changes in release 5.0.x (Development)

The following changelog shows what has already been done in the 5.0 tree:

Basic support for stored procedures (SQL:2003 style). See section 19 Stored Procedures and Functions.
Added SELECT INTO list_of_vars, which can be of mixed, that is, global and local type. See section 19.1.6.3 SELECT ... INTO Statement.
Removed the update log. It is fully replaced by the binary log. If the MySQL server is started with --log-update, it will be translated to --log-bin (or ignored if the server is explicitly started with --log-bin), and a warning message will be written to the error log. Setting SQL_LOG_UPDATE will silently set SQL_LOG_BIN instead (or do nothing if the server is explicitly started with --log-bin).
User variable names are now case insensitive: If you do SET @a=10; then SELECT @A; will now return 10. Case sensitivity of a variable's value depends on the collation of the value.

For a full list of changes, please refer to the changelog sections for each individual 5.0.x release.

C.1.1 Changes in release 5.0.1 (not released yet)

Functionality added or changed:

For replication of MEMORY (HEAP) tables: Made the master automatically write a DELETE FROM statement to its binary log when a MEMORY table is opened for the first time since master's startup. This is for the case where the slave has replicated a non-empty MEMORY table, then the master is shut down and restarted: the table is now empty on master; the DELETE FROM empties it on slave too. Note that even with this fix, between the master's restart and the first use of the table on master, the slave still has out of date data in the table. But if you use the --init-file option to populate the MEMORY table on the master at startup, it ensures that the failing time interval is zero. (Bug #2477)
When a session having open temporary tables terminates, the statement automatically written to the binary log is now DROP TEMPORARY TABLE IF EXISTS instead of DROP TEMPORARY TABLE, for more robustness.
The MySQL server now returns an error if SET SQL_LOG_BIN is issued by a user without the SUPER privilege (in previous versions it just silently ignored the statement in this case).
Changed that when the MySQL server has binary logging disabled (that is, no log-bin option was used) then no transaction binlog cache is allocated for connections (this should save binlog_cache_size bytes of memory (32 kilobytes by default) for every connection).

Bugs fixed:

Strange results with index (x, y) ... WHERE x=val_1 AND y>=val_2 ORDER BY pk; (Bug #3155)
Subquery and order by (Bug #3118)
ALTER DATABASE caused the client to hang if the database did not exist. (Bug #2333)
SLAVE START (which is a deprecated syntax, START SLAVE should be used instead) could crash the slave. (Bug #2516)
Multiple-table DELETE statements were never replicated by the slave if there were any replicate-*-table options. (Bug #2527)
The MySQL server did not report any error if the query (submitted through mysql_real_query() or mysql_prepare()) was terminated by garbage characters (which can happen if you pass a wrong length parameter to mysql_real_query() or mysql_prepare()); the result was that the garbage characters were written into the binary log. (Bug #2703)
Replication: If a client connects to a slave server and issues an administrative statement for a table (for example, OPTIMIZE TABLE or REPAIR TABLE), this could sometimes stop the slave SQL thread. This does not lead to any corruption, but you must use START SLAVE to get replication going again. (Bug #1858)
Made clearer the error message which one gets when an update is refused because of the read-only option. (Bug #2757)
Fixed that replicate-wild-*-table rules apply to ALTER DATABASE when the table pattern is '%', like it is already the case for CREATE DATABASE and DROP DATABASE. (Bug #3000)
Fixed that when a Rotate event is found by the slave SQL thread in the middle of a transaction, the value of Relay_Log_Pos in SHOW SLAVE STATUS remains correct. (Bug #3017)
Corrected the master's binary log position that InnoDB reports when it is doing a crash recovery on a slave server. (Bug #3015)
Changed the column Seconds_Behind_Master in SHOW SLAVE STATUS to never show a value of -1. (Bug #2826)
Changed that when a DROP TEMPORARY TABLE statement is automatically written to the binlog when a session ends, the statement is recorded with an error code of value zero (this ensures that killing a SELECT on the master does not result in a superfluous error on the slave). (Bug #3063)
Changed that when a thread handling INSERT DELAYED (also known as a delayed_insert thread) is killed, its statements are recorded with an error code of value zero (killing such a thread does not endanger replication, so we thus avoid a superfluous error on the slave). (Bug #3081)
Fixed deadlock when two START SLAVE commands were run at the same time. (Bug #2921)
Fixed that a statement never triggers a superfluous error on the slave, if it must be excluded given the replicate-* options. The bug was that if the statement had been killed on the master, the slave would stop. (Bug #2983)
The --local-load option of mysqlbinlog now requires an argument.
Fixed a segmentation fault when running LOAD DATA FROM MASTER after RESET SLAVE. (Bug #2922)
mysqlbinlog --read-from-remote-server read all binary logs following the one that was requested. It now stops at the end of the requested file, the same was it does when reading a local binary log. (Bug #3204)
Fixed mysqlbinlog --read-from-remote-server to print the exact positions of events in the "at #" lines. (Bug #3214)
Fixed a rare error condition that caused the slave SQL thread spuriously to print the message Binlog has bad magic number and stop when it was not necessary to do so. (Bug #3401)
Fixed mysqlbinlog not to forget to print a USE statement under rare circumstances where the binary log contained a LOAD DATA INFILE statement. (Bug #3415)
Fixed a memory corruption when replicating a LOAD DATA INFILE when the master had version 3.23. (Bug #3422)
Multiple-table DELETE statements were always replicated by the slave if there were some replicate-*-ignore-table options and no replicate-*-do-table options. (Bug #3461)

C.1.2 Changes in release 5.0.0 (22 Dec 2003: Alpha)

Functionality added or changed:

The KILL statement now takes CONNECTION and QUERY variants. The first is the same as KILL with no modifier (it kills a given connection thread). The second kills only the statement currently being executed by the connection.
Added TIMESTAMPADD() and TIMESTAMPDIFF() functions.
Added WEEK and QUARTER values as INTERVAL arguments for DATE_ADD() and DATE_SUB() functions.
New binary log format that enables replication of those session variables: SQL_MODE, SQL_AUTO_IS_NULL, FOREIGN_KEY_CHECKS (that one was already replicated since 4.0.14 but here it's done more efficiently: takes less space in the binary logs), UNIQUE_CHECKS. Other variables (like character sets, SQL_SELECT_LIMIT...) will be replicated in next 5.0.x releases.
Implemented Merge Index optimization for OR clauses. See section 7.2.5 How MySQL Optimizes OR Clauses.
Basic support for stored procedures (SQL:2003 style). See section 19 Stored Procedures and Functions.
Added SELECT INTO list_of_vars, which can be of mixed, that is, global and local type. See section 19.1.6.3 SELECT ... INTO Statement.
Easier replication upgrade (5.0.0 masters can read older binary logs, 5.0.0 slaves can read older relay logs; see section 6.5 Replication Compatibility Between MySQL Versions for more details). The format of the binary log and relay log is changed compared to the one of MySQL 4.1 and older.
Important note: If you upgrade to InnoDB-4.1.1 or higher, you cannot downgrade to a version lower than 4.1.1 any more! That is because earlier versions of InnoDB are not aware of multiple tablespaces.

Bugs fixed:

C.2 Changes in release 4.1.x (Alpha)

Version 4.1 of the MySQL server includes many enhancements and new features. Binaries for this version are available for download at http://www.mysql.com/downloads/mysql-4.1.html.

Subqueries and derived tables (unnamed views). See section 14.1.8 Subquery Syntax.
INSERT ... ON DUPLICATE KEY UPDATE ... syntax. This allows you to UPDATE an existing row if the insert would cause a duplicate value in a PRIMARY or UNIQUE key. (REPLACE allows you to overwrite an existing row, which is something entirely different.) See section 14.1.4 INSERT Syntax.
A newly designed GROUP_CONCAT() aggregate function. See section 13.9 Functions and Modifiers for Use with GROUP BY Clauses.
Extensive Unicode (UTF8) support.
Character sets can be defined per column, table, and database.
New key cache for MyISAM tables with many tunable parameters. You can have multiple key caches, preload index into caches for batches...
BTREE index on HEAP tables.
Support for OpenGIS spatial types (geographical data). See section 18 Spatial Extensions in MySQL.
SHOW WARNINGS shows warnings for the last command. See section 14.5.3.20 SHOW WARNINGS Syntax.
Faster binary protocol with prepared statements and parameter binding. See section 20.2.4 C API Prepared Statements.
You can now issue multiple statements with a single C API call and then read the results in one go. See section 20.2.8 C API Handling of Multiple Query Execution.
Create Table: CREATE [TEMPORARY] TABLE [IF NOT EXISTS] table2 LIKE table1.
Server based HELP command that can be used in the mysql command line client (and other clients) to get help for SQL statements.

For a full list of changes, please refer to the changelog sections for each individual 4.1.x release.

C.2.1 Changes in release 4.1.2 (not released yet)

Functionality added or changed:

Warning: Incompatible change! String comparison now works according to the SQL standard. Because we have that 'a' = 'a ' then from it must follow that 'a' > 'a\t'. (The latter was not the case before 4.1.2.) To implement it, we had to change how storage engines compare strings internally. As a side effect, if you have a table where a CHAR or VARCHAR column in some row has a value with the last character less than ASCII(32) you will have to repair this table. CHECK TABLES will tell you if this problem exists. (Bug #3152)
Added support for DEFAULT CURRENT_TIMESTAMP and for ON UPDATE CURRENT_TIMESTAMP specifications for TIMESTAMP columns. Now you can explicitly say that a TIMESTAMP column should be set automatically to the current timestamp for INSERT and/or UPDATE statements, or even prevent the column from updating automatically. Only one column with such an auto-set feature per table is supported. TIMESTAMP columns created with earlier versions of MySQL behave as before. Behavior of TIMESTAMP columns that were created without explicit specification of default/on as earlier depends on its position in table: If it is the first TIMESTAMP column, it will be treated as having been specified as TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP. In other cases, it would be treated as a TIMESTAMP DEFAULT 0 column. NOW is supported as an alias for CURRENT_TIMESTAMP. Warning: Incompatible change! Unlike in previous versions, explicit specification of default values for TIMESTAMP column is never ignored and turns off the auto-set feature (unless you have CURRENT_TIMESTAMP as the default).

Warning: Incompatible change! Renamed prepared statements C API functions:

Old Name	New Name
`mysql_bind_param()`	`mysql_stmt_bind_param()`
`mysql_bind_result()`	`mysql_stmt_bind_result()`
`mysql_prepare()`	`mysql_stmt_prepare()`
`mysql_execute()`	`mysql_stmt_execute()`
`mysql_fetch()`	`mysql_stmt_fetch()`
`mysql_fetch_column()`	`mysql_stmt_fetch_column()`
`mysql_param_count()`	`mysql_stmt_param_count()`
`mysql_param_result()`	`mysql_stmt_param_metadata()`
`mysql_get_metadata()`	`mysql_stmt_result_metadata()`
`mysql_send_long_data()`	`mysql_stmt_send_long_data()`

Now all functions that operate with a MYSQL_STMT structure begin with the prefix mysql_stmt_.

Warning: Incompatible change! The signature of the mysql_stmt_prepare() function was changed to int mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, unsigned long length). To create a MYSQL_STMT handle, you should use the mysql_stmt_init() function.
SHOW GRANTS with no FOR clause or with FOR CURRENT_USER() shows the privileges for the current session.
The improved character set support introduced in MySQL 4.1.0 for the MyISAM and HEAP storage engines is now available for InnoDB as well.
A key name of ``Primary'' is no longer allowed. (Bug #856)
MySQL now issues a warning when a SET or ENUM column with duplicate values in the list is created. (Bug #1427)
Now SQL_SELECT_LIMIT variable has no influence on subqueries. (Bug #2600)
UNHEX() function implemented. See section 13.3 String Functions.
History in command line client does not store multiple copies of identical queries that are run consecutively.
Multi-line queries in the command line client now are stored as a single line.
UUID() function implemented. Note that it does not work with replication yet. See section 13.8.4 Miscellaneous Functions.
Prepared statements with all types of subqueries fixed.
MyISAM tables now support keys up to 1000 bytes long.
If you try to create a key with a key part that is too long, and it is safe to auto-truncate it to a smaller length, MySQL now does so. A warning is generated, rather than an error.
The ft_boolean_syntax variable now can be changed while the server is running. See section 5.2.3 Server System Variables.
REVOKE ALL PRIVILEGES, GRANT FROM user_list is changed to a more consistent REVOKE ALL PRIVILEGES, GRANT OPTION FROM user_list. (Bug #2642)
Internal string-to-number conversion now supports only SQL:2003 compatible syntax for numbers. In particular, '0x10'+0 will not work anymore. (Actually, it worked only on some systems before, such as Linux. It did not work on others, such as FreeBSD or Solaris. Making these queries OS-independent was the goal of this change). Use CONV() to convert hexadecimal numbers to decimal. E.g. CONV(MID('0x10',3),16,10)+0.
mysqlhotcopy now works on NetWare.
ALTER TABLE DROP PRIMARY KEY no longer drops the first UNIQUE index if there is no primary index. (Bug #2361)
Added latin1_spanish_ci (Modern Spanish) collation for the latin1 character set.
Added the ENGINE table option as a synonym for the TYPE option for CREATE TABLE and ALTER TABLE.
Added the --default-storage-engine server option as a synonym for --default-table-type.
Added the storage_engine system variable as a synonym for table_type.
Added init_connect and init_slave server variables. The values should be SQL statements to be executed when each client connects or each time a slave's SQL thread starts, respectively.
C API enhancement: SERVER_QUERY_NO_INDEX_USED and SERVER_QUERY_NO_GOOD_INDEX_USED flags are now set in the server_status field of the MYSQL structure. It is these flags that make the query to be logged as slow if mysqld was started with --log-slow-queries --log-queries-not-using-indexes.
For replication of MEMORY (HEAP) tables: Made the master automatically write a DELETE FROM statement to its binary log when a MEMORY table is opened for the first time since master's startup. This is for the case where the slave has replicated a non-empty MEMORY table, then the master is shut down and restarted: the table is now empty on master; the DELETE FROM empties it on slave too. Note that even with this fix, between the master's restart and the first use of the table on master, the slave still has out of date data in the table. But if you use the init-file option to populate the MEMORY table on the master at startup, it ensures that the failing time interval is zero. (Bug #2477)
When a session having open temporary tables terminates, the statement automatically written to the binary log is now DROP TEMPORARY TABLE IF EXISTS instead of DROP TEMPORARY TABLE, for more robustness.
The MySQL server now returns an error if SET SQL_LOG_BIN or SET SQL_LOG_UPDATE is issued by a user without the SUPER privilege (in previous versions it just silently ignored the statement in this case).
Changed that when the MySQL server has binary logging disabled (that is, no log-bin option was used) then no transaction binlog cache is allocated for connections (this should save binlog_cache_size bytes of memory (32 kilobytes by default) for every connection).
Added Binlog_cache_use and Binlog_cache_disk_use status variables that count the number of transactions that used transaction binary log and that had to flush this temporary binary log to disk instead of using only buffer in memory. They can be used for tuning the binlog_cache_size system variable.

Bugs fixed:

Fixed crash in prepared statements when subquery in the FROM clause with parameter used. (Bug #3020)
Fixed unknown error when negative value bind to unsigned. (Bug #3223)
Fixed aggregate function in prepared statements. (Bug #3360)
Incorrect error message when wrong table used in multi-delete statement in prepared statements. (Bug #3411)
Requiring UPDATE privilege for tables which will not be updated in multi-update query in prepared statements.
Fixed prepared statement support for INSERT, REPLACE, CREATE, DELETE, SELECT, DO, SET and SHOW. All other commands are prohibited via prepared statement interface. (Bug ##3398, Bug #3406, Bug #2811)
Fixed a lot of bugs in GROUP_CONCAT(). (Bug #2695, Bug #3381, Bug #3319)
Added optimization that allows for prepared statements using a large number of tables or tables with a large number of columns to be re-executed significantly faster. (Bug #2050)
Fixed bug that caused execution of prepared statements to fail then table that this statement were using left table cache. This bug showed up as if this prepared statement used random garbage as column names or as server crashes. (Bug #3307)
Fixed a problem resulting from setting the character_set_results variable to NULL. (Bug #3296)
Fixed query cache statistics.
Fixed bug in ANALYZE TABLE on a BDB table inside a transaction that hangs server thread. (Bug #2342)
Fixed a symlink vulnerability in `mysqlbug' script. (Bug #3284)
Fixed a bug in parallel repair (myisamchk -p, myisam_repair_threads); sometimes the repair process failed to repair a table. (Bug #1334)
A query that uses both UNION [DISTINCT] and UNION ALL now works correctly. (Bug #1428)
Table default character set affects LONGBLOB columns. (Bug #2821)
CONCAT_WS() makes the server die in case of illegal mix of collations. (Bug #3087)
UTF8 charset breaks joins with mixed column/string constant. (Bug #2959)
Fixed DROP DATABASE to report number of tables deleted.
Fixed memory leak in the client library when statement handle was freed on closed connection (call to mysql_stmt_close after mysql_close). (Bug #3073)
Fixed server segfaults when processing malformed prepared statements commands. (Bug #2795, Bug #2274)
Fixed using subqueries with OR and AND functions. (Bug #2838)
Fixed comparison of tables/database names with --lower_case_table_names option. (Bug #2880)
Removed try to check NULL if index built on column where NULL is impossible in IN subquery optimization. (Bug #2393)
Fixed incorrect parsing of subqueries in the FROM clause. (Bug #2421)
Fixed processing of RAND() in subqueries with static tables. (bug #2645)
Fixed bug with quoting of table names in mysqldump for various values of sql_mode of server. (Bug #2591)
Fixed bug with storing values that are out of range for DOUBLE and FLOAT columns. (Bug #2082)
Fixed bug with compiling --with-pstack with binutils 2.13.90. (Bug #1661)
Fixed a bug in the GRANT system. When a password was assigned to an account at the global level and then privileges were granted at the database level (without specifying any password), the existing password was replaced temporarily in memory until the next FLUSH PRIVILEGES operation or the server was restarted. (Bug #2953)
Fixed a bug in full-text search on multi-byte character set (such as UTF8) that appeared when a search word was shorter than a matching word from the index (for example, searching for ``Uppsala'' when table data contain ``Uppsåla''). (Bug #3011)
Fixed a bug that made Max_used_connections to be less than the actual maximum number of connections in use simultaneously.
Fixed calculation of Index_length in HEAP table status for BTREE indexes. (Bug #2719)
Fixed mysql_stmt_affected_rows() call to always return number of rows affected by given statement. (Bug #2247)
Fixed crash in MATCH ... AGAINST() on a phrase search operator with a missing closing double quote. (Bug #2708)
Fixed output of mysqldump --tab. (Bug #2705)
Fix for a bug in UNION operations that prevented proper handling of NULL columns. This happened only if a column in the first SELECT node was NOT NULL. (Bug #2508)
Fix for a bug in UNION operations with InnoDB storage engine, when some columns from one table where used in one SELECT statement and some were used in another SELECT statement. (Bug #2552)
Fixed a few years old bug in the range optimizer that caused a segmentation fault on some very rare queries. (Bug #2698)
Fixed bug with SHOW CREATE TABLE ... which didn't properly double quotes. (Bug #2593)
Queries with subqueries in FROM clause locks all tables at once for now. This also fixed bugs in EXPLAIN of subqueries in FROM output. (Bug #2120)
Fixed bug with mysqldump not quoting ``tricky'' names correctly. (Bug #2592)
Fix for a bug that prevented table / column privileges from being loaded on startup. (Bug #2546)
Fixed bug in replication with CREATE TABLE ... LIKE ... that resulted in a statement not being written to the binary log. (Bug #2557)
Fixed memory leak in INSERT ... ON DUPLICATE KEY UPDATE .... (Bug #2438)
Fixed bug in the parser, making the syntax CONVERT(expression,type) legal again.
Fixed parsing of short-form IP addresses in INET_ATON(). (Bug #2310)
Fixed a bug in CREATE ... SELECT that sometimes caused a string column with a multi-byte character set (such as utf8) to have insufficient length to hold the data.
Fixed a rare table corruption on adding data (INSERT, REPLACE, UPDATE, etc. but not DELETE) to a FULLTEXT index. (Bug #2417)
Compile the MySQL-client RPM package against libreadline instead of libedit. (Bug #2289)
Fix for a crashing bug that was caused by not setting vio_timeout() virtual function for all protocols. This bug occurred on Windows. (Bug #2025)
Fix for a bug that caused mysql client program to erroneously cache the value of the current database. (Bug #2025)
Fix for a bug that caused client/server communication to be broken when mysql_set_server_option() or mysql_get_server_option() were invoked. (Bug #2207)
Fix for a bug that caused wong results when CAST() was applied on NULL to signed or unsigned integer column. (Bug #2219)
Fix for a crashing bug that occurred in the mysql client program when database name was longer then expected. (Bug #2221)
Fixed a bug in CHECK TABLE that occasionally resulted in spurious "Found key at page ... that points to record outside datafile" error on a table with a FULLTEXT index. (Bug #2190)
Fixed bug in GRANT with table-level privilege handling. (Bug #2178)
Fixed bug in ORDER BY on a small column. (Bug #2147)
Fixed a bug with the INTERVAL() function when 8 or more comparison arguments are provided. (Bug #1561)
Packaging: Fixed a bug in the Mac OS PKG postinstall script (mysql_install_db was called with an obsolete argument).
Packaging: Added missing file `mysql_create_system_tables' to the server RPM package. This bug was fixed for the 4.1.1 RPMs by updating the MySQL-server RPM from MySQL-server-4.1.1-0 to MySQL-server-4.1.1-1. The other RPMs were not affected by this change.
Fixed a bug in `myisamchk' and CHECK TABLE that sometimes resulted in a spurious error Found key at page ... that points to record outside datafile for a table with a FULLTEXT index. (Bug #1977)
Fixed a hang in full-text indexing of strings in multi-byte (all besides utf8) charsets. (Bug #2065)
Fixed a crash in full-text indexing of UTF8 data. (Bug #2033)
Replication: a rare race condition in the slave SQL thread that could lead to an incorrect complaint that the relay log is corrupted. (Bug #2011)
Replication: If a client connects to a slave server and issues an administrative statement for a table (for example, OPTIMIZE TABLE or REPAIR TABLE), this could sometimes stop the slave SQL thread. This does not lead to any corruption, but you must use START SLAVE to get replication going again. (Bug #1858)
Replication: in the slave SQL thread, a multiple-table UPDATE could produce an incorrect complaint that some record was not found in one table, if the UPDATE was preceded by a INSERT ... SELECT. (Bug #1701)
Replication: sometimes the master gets a non-fatal error during the execution of a statement but finally the statements succeeds (for example, a write to a MyISAM table first receives "no space left on device" but is able to finally complete, see section A.4.3 How MySQL Handles a Full Disk); the bug was that the master forgot to reset the error code to 0 after success, so the error code got into its binary log, thus making the slave giving false alarms like "did not get the same error as on master". (Bug #2083)
Removed a misleading "check permissions on master.info" from a replication error message, because the cause of the problem could be different from permissions. (Bug #2121)
Fixed a crash when the replication slave was unable to create the first relay log. (Bug #2145)
ALTER DATABASE caused the client to hang if the database did not exist. (Bug #2333)
Multiple-table DELETE statements were never replicated by the slave if there were any replicate-*-table options. (Bug #2527)
Fixed bug in ALTER TABLE RENAME, when rename to the table with the same name in another database silently dropped destination table if it existed. (Bug #2628)
The MySQL server did not report any error if the query (submitted through mysql_real_query() or mysql_prepare()) was terminated by garbage characters (which can happen if you pass a wrong length parameter to mysql_real_query() or mysql_prepare()); the result was that the garbage characters were written into the binary log. (Bug #2703)
Fixed bug in client library which caused mysql_fetch and mysql_stmt_store_result() to hang if they were called without prior call of mysql_execute(). Now they give an error instead. (Bug #2248)
Made clearer the error message which one gets when an update is refused because of the read-only option. (Bug #2757)
Fixed that replicate-wild-*-table rules apply to ALTER DATABASE when the table pattern is '%', like it is already the case for CREATE DATABASE and DROP DATABASE. (Bug #3000)
Fixed that when a Rotate event is found by the slave SQL thread in the middle of a transaction, the value of Relay_Log_Pos in SHOW SLAVE STATUS remains correct. (Bug #3017)
Corrected the master's binary log position that InnoDB reports when it is doing a crash recovery on a slave server. (Bug #3015)
Changed the column Seconds_Behind_Master in SHOW SLAVE STATUS to never show a value of -1. (Bug #2826)
Changed that when a DROP TEMPORARY TABLE statement is automatically written to the binary log when a session ends, the statement is recorded with an error code of value zero (this ensures that killing a SELECT on the master does not result in a superfluous error on the slave). (Bug #3063)
Changed that when a thread handling INSERT DELAYED (also known as a delayed_insert thread) is killed, its statements are recorded with an error code of value zero (killing such a thread does not endanger replication, so we thus avoid a superfluous error on the slave). (Bug #3081)
Fixed deadlock when two START SLAVE commands were run at the same time. (Bug #2921)
Fixed that a statement never triggers a superfluous error on the slave, if it must be excluded given the replicate-* options. The bug was that if the statement had been killed on the master, the slave would stop. (Bug #2983)
The --local-load option of mysqlbinlog now requires an argument.
Fixed a segmentation fault when running LOAD DATA FROM MASTER after RESET SLAVE. (Bug #2922)
mysqlbinlog --read-from-remote-server read all binary logs following the one that was requested. It now stops at the end of the requested file, the same was it does when reading a local binary log. (Bug #3204)
Fixed mysqlbinlog --read-from-remote-server to print the exact positions of events in the "at #" lines. (Bug #3214)
Fixed a rare error condition that caused the slave SQL thread spuriously to print the message Binlog has bad magic number and stop when it was not necessary to do so. (Bug #3401)
Fixed the Exec_master_log_pos column and its disk image in the `relay-log.info' file to be correct if the master had version 3.23. (The value was too big by six bytes.) This bug does not exist in MySQL 5.0. (Bug #3400)
Fixed mysqlbinlog not to forget to print a USE statement under rare circumstances where the binary log contained a LOAD DATA INFILE statement. (Bug #3415)
Fixed a memory corruption when replicating a LOAD DATA INFILE when the master had version 3.23. Some smaller problems remain in this setup, See section 6.7 Replication Features and Known Problems. (Bug #3422)
Multiple-table DELETE statements were always replicated by the slave if there were some replicate-*-ignore-table options and no replicate-*-do-table options. (Bug #3461)

C.2.2 Changes in release 4.1.1 (01 Dec 2003)

This release includes all fixes in MySQL 4.0.16 and most of the fixes in MySQL 4.0.17.

Functionality added or changed:

New CHECKSUM TABLE statement for reporting table checksum values.
Added character_set_client, character_set_connection, character_set_database, character_set_results, character_set_server, character_set_system, collation_connection, collation_database, and collation_server system variables to provide information about character sets and collations.
It is now possible to create multiple key caches, assign table indexes to particular caches, and to preload indexes into caches. See section 14.5.4.1 CACHE INDEX Syntax. See section 14.5.4.4 LOAD INDEX INTO CACHE Syntax. Structured system variables are introduced as a means of grouping related key cache parameters. See section 10.4.1 Structured System Variables.
New COERCIBILITY() function to return the collation coercibility of a string.
The --quote-names option for mysqldump now is enabled by default.
mysqldump now includes a statement in the dump output to set FOREIGN_KEY_CHECKS to 0 to avoid problems with tables having to be reloaded in a particular order when the dump is reloaded. The existing FOREIGN_KEY_CHECKS value is saved and restored.
Important note: If you upgrade to InnoDB-4.1.1 or higher, you cannot downgrade to a version lower than 4.1.1 any more! That is because earlier versions of InnoDB are not aware of multiple tablespaces.
One can revoke all privileges from a user with REVOKE ALL PRIVILEGES, GRANT FROM user_list.
Added IGNORE option for DELETE statement.
The MySQL source distribution now also includes the MySQL Internals Manual `internals.texi'.
Added mysql_set_server_option() C API client function to allow multiple statement handling in the server to be enabled or disabled.
The mysql_next_result() C API function now returns -1 if there are no more result sets.
Renamed CLIENT_MULTI_QUERIES connect option flag to CLIENT_MULTI_STATEMENTS. To allow for a transition period, the old option will continue to be recognized for a while.
Require DEFAULT before table and database default character set. This enables us to use ALTER TABLE tbl_name ... CHARACTER SET=... to change the character set for all CHAR, VARCHAR, and TEXT columns in a table.
Added MATCH ... AGAINST( ... WITH QUERY EXPANSION) and the ft_query_expansion_limit server variable.
Removed unused ft_max_word_len_for_sort server variable.
Full-text search now supports multi-byte character sets and the Unicode utf8 character set. (The Unicode ucs2 character set is not yet supported.)
Phrase search in MATCH ... AGAINST ( ... IN BOOLEAN MODE) no longer matches partial words.
Added aggregate function BIT_XOR() for bitwise XOR operations.
Replication over SSL now works.
The START SLAVE statement now supports an UNTIL clause for specifying that the slave SQL thread should be started but run only until it reaches a given position in the master's binary logs or in the slave's relay logs.
Produce warnings even for single-row INSERT statements, not just for multiple-row INSERT statements. Previously, it was necessary to set SQL_WARNINGS=1 to generate warnings for single-row statements.
Added delimiter (\d) command to the mysql command-line client for changing the statement delimiter (terminator). The default delimiter is semicolon.
CHAR, VARCHAR, and TEXT columns now have lengths measured in characters rather than in bytes. The character size depends on the column's character set. This means, for example, that a CHAR(n) column for a multi-byte character set will take more storage than before. Similarly, index values on such columns are measured in characters, not bytes.
LIMIT no longer accepts negative arguments (they used to be treated as very big positive numbers before).
The DATABASE() function now returns NULL rather than the empty string if there is no database selected.
Added --sql-mode=NO_AUTO_VALUE_ON_ZERO option to suppress the usual behavior of generating the next sequence number when zero is stored in an AUTO_INCREMENT column. With this mode enabled, zero is stored as zero; only storing NULL generates a sequence number.
Warning: Incompatible change! Client authentication now is based on 41-byte passwords in the user table, not 45-byte passwords as in 4.1.0. Any 45-byte passwords created for 4.1.0 must be reset after running the mysql_fix_privilege_tables script.
Added secure_auth global server system variable and --secure-auth server option that disallow authentication for accounts that have old (pre-4.1.1) passwords.
Added --secure-auth option to mysql command-line client. If this option is set, the client refuses to send passwords in old (pre-4.1.1) format.
Warning: Incompatible change! Renamed the C API mysql_prepare_result() function to mysql_get_metadata() as the old name was confusing.
Added DROP USER 'username'@'hostname' statement to drop an account that has no privileges.
The interface to aggregated UDF functions has changed a bit. You must now declare a xxx_clear() function for each aggregate function XXX().
Added new ADDTIME(), DATE(), DATEDIFF(), LAST_DAY(), MAKEDATE(), MAKETIME(), MICROSECOND(), SUBTIME(), TIME(), TIMEDIFF(), TIMESTAMP(), UTC_DATE(), UTC_TIME(), UTC_TIMESTAMP(), and WEEKOFYEAR() functions.
Added new syntax for ADDDATE() and SUBDATE(). The second argument now may be a number representing the number of days to be added to or subtracted from the first date argument.
Added new type values DAY_MICROSECOND, HOUR_MICROSECOND, MINUTE_MICROSECOND, SECOND_MICROSECOND, and MICROSECOND for DATE_ADD(), DATE_SUB(), and EXTRACT().
Added new %f microseconds format specifier for DATE_FORMAT() and TIME_FORMAT().
All queries in which at least one SELECT does not use indexes properly now are written to the slow query log when long log format is used.
It is now possible to create a MERGE table from MyISAM tables in different databases. Formerly, all the MyISAM tables had to be in the same database, and the MERGE table had to be created in that database as well.
Added new COMPRESS(), UNCOMPRESS(), and UNCOMPRESSED_LENGTH() functions.
When using SET sql_mode='mode' for a complex mode (like ANSI), we now update the sql_mode variable to include all the individual options implied by the complex mode.
Added the OLAP (On-Line Analytical Processing) function ROLLUP, which provides summary rows for each GROUP BY level.
Added SQLSTATE codes for all server errors.
Added mysql_sqlstate() and mysql_stmt_sqlstate() C API client functions that return the SQLSTATE error code for the last error.
TIME columns with hour values greater than 24 were returned incorrectly to the client.
ANALYZE, OPTIMIZE, REPAIR, and FLUSH statements are now stored in the binary log and thus replicated to slaves. This logging does not occur if the optional NO_WRITE_TO_BINLOG keyword (or its alias LOCAL) is given. Exceptions are that FLUSH LOGS, FLUSH MASTER, FLUSH SLAVE, and FLUSH TABLES WITH READ LOCK are not logged in any case. For a syntax example, see section 14.5.4.2 FLUSH Syntax.
New global system variable relay_log_purge to enable or disable automatic relay log purging.
LOAD DATA now produces warnings that can be fetched with SHOW WARNINGS.
Added support for syntax CREATE TABLE table2 (LIKE table1) that creates an empty table table2 with a definition that is exactly the same as table1, including any indexes.
CREATE TABLE tbl_name (...) TYPE=storage_engine now generates a warning if the named storage engine is not available. The table is still created as a MyISAM table, as before.
Most subqueries are now much faster than before.
Added PURGE BINARY LOGS as an alias for PURGE MASTER LOGS.
Disabled the PURGE LOGS statement that was added in in version 4.1.0. The statement now should be issued as PURGE MASTER LOGS or PURGE BINARY LOGS.
Added SHOW BDB LOGS as an alias for SHOW LOGS.
Added SHOW MASTER LOGS (which had been deleted in version 4.1.0) as an alias for SHOW BINARY LOGS.
Added Slave_IO_State and Seconds_Behind_Master columns to the output of SHOW SLAVE STATUS. Slave_IO_State indicates the state of the slave I/O thread, and Seconds_Behind_Master indicates the number of seconds by which the slave is late compared to the master.
The --lower-case-table-names=1 server option now also makes aliases case insensitive. (Bug #534)
Changed that the relay log is flushed to disk by the slave I/O thread every time it reads a relay log event. This reduces the risk of losing some part of the relay log in case of brutal crash.

Bugs fixed:

Fixed mysql parser not to erroneously interpret `;' character within /* ... */ comment as statement terminator.
Fixed merging types and length of result set columns for UNION operations. The types and lengths now are determined taking into account values for all SELECT statements in the UNION, not just the first SELECT.
Fixed a bug in privilege handling that caused connections from certain IP addresses to be assigned incorrect database-level privileges. A connection could be assigned the database privileges of the previous successful authentication from one of those IP addresses, even if the IP address username and database name were different. (Bug #1636)
Error-handling functions were not called properly when an error resulted from [CREATE | REPLACE| INSERT] ... SELECT statements.
HASH, BTREE, RTREE, ERRORS, and WARNINGS no longer are reserved words. (Bug #724)
Fix for bug in ROLLUP when all tables were const tables. (Bug #714)
Fixed a bug in UNION that prohibited NULL values from being inserted into result set columns where the first SELECT of the UNION retrieved NOT NULL columns. The type and max_length of the result column is now defined based on all UNION parts.
Fixed name resolution of columns of reduced subqueries in unions. (Bug #745)
Fixed memory overrun in subqueries in select list with WHERE clause bigger than outer query WHERE clause. (Bug #726)
Fixed a bug that caused MyISAM tables with FULLTEXT indexes created in 4.0.x to be unreadable in 4.1.x.
Fixed a data loss bug in REPAIR TABLE ... USE_FRM when used with tables that contained TIMESTAMP columns and were created in 4.0.x.
Fixed reduced subquery processing in ORDER BY/GROUP BY clauses. (Bug #442)
Fixed name resolution of outer columns of subquery in INSERT/REPLACE statements. (Bug #446)
Fixed bug in marking columns of reduced subqueries. (Bug #679)
Fixed a bug that made CREATE FULLTEXT INDEX syntax illegal.
Fixed a crash when a SELECT that required a temporary table (marked by Using temporary in EXPLAIN output) was used as a derived table in EXPLAIN command. (Bug #251)
Fixed a rare table corruption bug in DELETE from a big table with a new (created by MySQL-4.1) full-text index.
LAST_INSERT_ID() now returns 0 if the last INSERT statement didn't insert any rows.
Fixed missing last character in function output. (Bug #447)
Fixed a rare replication bug when a transaction spanned two or more relay logs, and the slave was stopped while executing the part of the transaction that was in the second or later relay log. Then replication would resume at the beginning of the second or later relay log, which was incorrect. (It should resume at BEGIN, in the first relay log.) (Bug #53)
CONNECTION_ID() now is properly replicated. (Bug #177)
The new PASSWORD() function in 4.1 is now properly replicated. (Bug #344)
Fixed a bug with double freed memory.
Fixed a crashing bug in UNION operations that involved temporary tables.
Fixed a crashing bug in DERIVED TABLES when EXPLAIN is used on a DERIVED TABLES with a join.
Fixed a crashing bug in DELETE with ORDER BY and LIMIT caused by an uninitialized array of reference pointers.
Fixed a bug in the USER() function caused by an error in the size of the allocated string.
Fixed a crashing bug when attempting to create a table containing a spatial (GIS) column with a storage engine that does not support spatial types.
Fixed a crashing bug in UNION caused by the empty select list and a non-existent column being used in some of the individual SELECT statements.
Fixed a replication bug with a 3.23 master and a 4.0 slave: The slave lost the replicated temporary tables if FLUSH LOGS was issued on the master. (Bug #254)
Fixed a security bug: A server compiled without SSL support still allowed connections by users that had the REQUIRE SSL option specified for their accounts.
When an undefined user variable was used in a updating query on the master (such as INSERT INTO t VALUES(@a), where @a had never been set by this connection before), the slave could replicate the query incorrectly if a previous transaction on the master used a user variable of the same name. (Bug #1331)
Fixed bug with prepared statements: Using the ? prepared statement parameter as the argument to certain functions or statement clauses caused a server crash when mysql_prepare() was invoked. (Bug #1500)
Fixed bug with prepared statements: after call to mysql_prepare placeholders became allowed in all consequent statements, even if they are not prepared (Bug #1946)
SLAVE START (which is a deprecated syntax, START SLAVE should be used instead) could crash the slave. (Bug #2516)
Fixed bug in ALTER TABLE RENAME, when rename to the table with the same name in another database silently dropped destination table if it existed. (Bug #2628)

C.2.3 Changes in release 4.1.0 (03 Apr 2003: Alpha)

Functionality added or changed:

Added --compatible option to mysqldump for producing output that is compatible with other database systems or with older MySQL servers.
The --opt option for mysqldump now is enabled by default, as are all the options implied by --opt.
New CHARSET() and COLLATION() functions to return the character set and collation of a string.
Allow index type to be specified explicitly for some storage engines via USING type_name syntax in index definition.
New function IS_USED_LOCK() for determining the connection identifier of the client that holds a given advisory lock.
New more secure client authentication based on 45-byte passwords in the user table.
New CRC32() function to compute cyclic redundancy check value.
On Windows, we are now using shared memory to communicate between server and client when they are running on the same machine and you are connecting to localhost.
REPAIR of MyISAM tables now uses less temporary disk space when sorting char columns.
DATE/DATETIME checking is now a bit stricter to support the ability to automatically distinguish between date, datetime, and time with microseconds. For example, dates of type YYYYMMDD HHMMDD are no longer supported; you must either have separators between each DATE/TIME part or not at all.
Server side help for all MySQL functions. One can now type help week in the mysql client and get help for the week() function.
Added new mysql_get_server_version() C API client function.
Fixed bug in libmysqlclient that fetched column defaults.
Fixed bug in `mysql' command-line client in interpreting quotes within comments. (Bug #539)
Added record_in_range() method to MERGE tables to be able to choose the right index when there are many to choose from.
Replication now works with RAND() and user variables @var.
Allow one to change mode for ANSI_QUOTES on the fly.
EXPLAIN SELECT now can be killed. See section 14.5.4.3 KILL Syntax.
REPAIR TABLE now can be killed. See section 14.5.4.3 KILL Syntax.
Allow empty index lists to be specified for USE INDEX, IGNORE INDEX, and FORCE INDEX.
DROP TEMPORARY TABLE now drops only temporary tables and doesn't end transactions.
Added support for UNION in derived tables.
Warning: Incompatible change! TIMESTAMP is now returned as a string of type 'YYYY-MM-DD HH:MM:SS' and different timestamp lengths are not supported. This change was necessary for SQL standards compliance. In a future version, a further change will be made (backward compatible with this change), allowing the timestamp length to indicate the desired number of digits of fractions of a second.
New faster client/server protocol that supports prepared statements, bound parameters, and bound result columns, binary transfer of data, warnings.
Added database and real table name (in case of alias) to the MYSQL_FIELD structure.
Multi-line queries: You can now issue several queries at once and then read the results in one go.
In CREATE TABLE foo (a INT not null primary key) the PRIMARY word is now optional.
In CREATE TABLE the attribute SERIAL is now an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE.
SELECT ... FROM DUAL is an alias for SELECT .... (To be compatible with some other databases).
If one creates a too long CHAR/VARCHAR it's now automatically changed to TEXT or BLOB; One will get a warning in this case.
One can specify the different BLOB/TEXT types with the syntax BLOB(length) and TEXT(length). MySQL will automatically change it to one of the internal BLOB/TEXT types.
CHAR BYTE is an alias for CHAR BINARY.
VARCHARACTER is an alias for VARCHAR.
New operators integer MOD integer and integer DIV integer.
SERIAL DEFAULT VALUE added as an alias for AUTO_INCREMENT.
TRUE and FALSE added as alias for 1 and 0, respectively.
Aliases are now forced in derived tables, as per standard SQL.
Fixed SELECT .. LIMIT 0 to return proper row count for SQL_CALC_FOUND_ROWS.
One can specify many temporary directories to be used in a round-robin fashion with: --tmpdir=dirname1:dirname2:dirname3.
Subqueries: SELECT * from t1 where t1.a=(SELECT t2.b FROM t2).

Derived tables:

SELECT a.col1, b.col2
       FROM (SELECT MAX(col1) AS col1 FROM root_table) a,
       other_table b
       WHERE a.col1=b.col1;

Character sets to be defined per column, table and database.
Unicode (UTF8) support.
New CONVERT(... USING ...) syntax for converting string values between character sets.
BTREE index on MEMORY (HEAP) tables.
Faster embedded server (new internal communication protocol).
One can add a comment per column in CREATE TABLE.
SHOW FULL COLUMNS FROM tbl_name shows column comments.
ALTER DATABASE.
Support for GIS (Geometrical data). See section 18 Spatial Extensions in MySQL.
SHOW [COUNT(*)] WARNINGS shows warnings from the last command.
One can specify a column type for a column in CREATE TABLE ... SELECT by defining the column in the CREATE part.
```
CREATE TABLE foo (a TINYINT NOT NULL) SELECT b+1 AS a FROM bar;
```
expr SOUNDS LIKE expr same as SOUNDEX(expr)=SOUNDEX(expr).
Added new VARIANCE(expr) function returns the variance of expr
One can create a table from the existing table using CREATE [TEMPORARY] TABLE [IF NOT EXISTS] table (LIKE table). The table can be either normal or temporary.
New options --reconnect and --skip-reconnect for the mysql client, to reconnect automatically or not if the connection is lost.
START SLAVE (STOP SLAVE) no longer returns an error if the slave is already started (stopped); it returns a warning instead.
SLAVE START and SLAVE STOP are no longer accepted by the query parser; use START SLAVE and STOP SLAVE instead.

C.3 Changes in release 4.0.x (Production)

Version 4.0 of the MySQL server includes many enhancements and new features:

The InnoDB storage engine is now included in the standard binaries, adding transactions, row-level locking, and foreign keys. See section 16 The InnoDB Storage Engine.
A query cache, offering vastly increased performance for many applications. By caching complete result sets, later identical queries can return instantly. See section 5.10 The MySQL Query Cache.
Improved full-text indexing with boolean mode, truncation, and phrase searching. See section 13.6 Full-text Search Functions.
Enhanced MERGE tables, now supporting INSERT statements and AUTO_INCREMENT. See section 15.2 The MERGE Storage Engine.
UNION syntax in SELECT. See section 14.1.7.2 UNION Syntax.
Multiple-table DELETE statements. See section 14.1.1 DELETE Syntax.
libmysqld, the embedded server library. See section 20.2.15 libmysqld, the Embedded MySQL Server Library.
Additional GRANT privilege options for even tighter control and security. See section 14.5.1.2 GRANT and REVOKE Syntax.
Management of user resources in the GRANT system, particularly useful for ISPs and other hosting providers. See section 5.5.5 Limiting Account Resources.
Dynamic server variables, allowing configuration changes to be made without having to stop and restart the server. See section 14.5.3.1 SET Syntax.
Improved replication code and features. See section 6 Replication in MySQL.
Numerous new functions and options.
Changes to existing code for enhanced performance and reliability.

For a full list of changes, please refer to the changelog sections for each individual 4.0.x release.

C.3.1 Changes in release 4.0.19 (not released yet)

Functionality added or changed:

Changed that the optimizer will now consider the index specified in FORCE INDEX clause as a candidate to resolve ORDER BY as well.
Non-standard behavior of UNION statements has changed to the standard ones. So far, a table name in the ORDER BY clause was tolerated. From now on a proper error message is issued (Bug #3064).
Added max_insert_delayed_threads system variable as a synonym for max_delayed_threads.
Added query_cache_wlock_invalidate system variable. It allow emulation of MyISAM table write-locking behavior, even for queries in the query cache. (Bug #2693)
The keyword MASTER_SERVER_ID is not reserved anymore.
The following is mainly relevant for Mac OS X users that use a case-insensitive filesystem. This is not relevant for Windows users as InnoDB in this case always stores file names in lower case: One can now force lower_case_table_names to 0 from the command line or a configuration file. This is useful with case-insensitive filesystems when you have previously not used lower_case_table_names=1 or lower_case_table_names=2 and your have already created InnoDB tables. With lower_case_table_names=0, InnoDB tables were stored in mixed case while setting lower_case_table_names <> 0 will now force it to lower case (to make the table names case insensitive). Because it's possible to crash MyISAM tables by referring to them with different case on a case-insensitive filesystem, we recommend that you use lower_case_table_names or lower_case_table_names=2 on such filesystems. The easiest way to convert to use lower_case_table_names=2 is to dump all your InnoDB tables with mysqldump, drop them and then restore them.
Non-standard behavior of UNION statements has changed to the standard ones. So far, a table name in the ORDER BY clause was tolerated. From now on a proper error message is issued (Bug #3064).
Added max_insert_delayed_threads system variable as a synonym for max_delayed_threads.
Added query_cache_wlock_invalidate system variable. It allow emulation of MyISAM table write-locking behavior, even for queries in the query cache. (Bug #2693)
Changed that the relay log is flushed to disk by the slave I/O thread every time it reads a relay log event. This reduces the risk of losing some part of the relay log in case of brutal crash.
When a session having open temporary tables terminates, the statement automatically written to the binary log is now DROP TEMPORARY TABLE IF EXISTS instead of DROP TEMPORARY TABLE, for more robustness.

Bugs fixed:

Fixed a bug in MATCH ... AGAINST() searches when another thread was doing concurrent inserts into the MyISAM table in question. The first --- full-text search -- query could return incorrect results in this case (e.g. ``phantom'' rows or not all matching rows, even an empty result set). The easiest way to check whether you are affected is to start `mysqld' with --skip-concurrent-insert switch and see if it helps.
Fixed bug when doing DROP DATABASE on a directory containing non- MySQL files. Now a proper error message is returned.
Fixed bug in ANALYZE TABLE on a BDB table inside a transaction that hangs server thread. (Bug #2342)
Fixed a symlink vulnerability in `mysqlbug' script. (Bug #3284)
Fixed core dump bug in SELECT DISTINCT where all selected parts where constants and there were hidden columns in the created temporary table. (Bug #3203)
Fixed core dump bug in COUNT(DISTINCT) when there was a lot of values and one had a big value for max_heap_table_size.
Fixed problem with multi-table-update and BDB tables. (Bug: #3098)
Fixed memory leak when dropping database with RAID tables. (Bug #2882)
Fixed core dump crash in replication during relay-log switch when the relay log went over max_relay_log_size and the slave thread did a flush_io_cache() at the same time.
Fixed hangup bug when issuing multiple SLAVE START from different threads at the same time. (Bug #2921)
Fixed bug when using DROP DATABASE with lower_case_table_names=2.
Fixed wrong result in UNION when using lower_case_table_names=2. (Bug #2858)
One can now kill threads that is 'stuck' in the join optimizer (can happen when there is MANY tables in the join in which case the optimizer can take really long time). (Bug #2825)
Rollback DELETE and UPDATE statements if thread is killed. (Bug #2422)
Ensure that all rows in an INSERT DELAYED statement is written at once if binary logging is enabled. (Bug #2491).
Fixed bug in query cache statistic, more accurate formula linked statistic variables mentioned in the manual.
Fixed a bug in parallel repair (myisamchk -p, myisam_repair_threads) - sometimes repair process failed to repair a table. (Bug #1334)
Fixed bugs with names of tables, databases and columns that end to space (Bug #2985)
Fixed a bug in multiple-table UPDATE statements involving at least one constant table. Bug was exhibited in allowing non matching row to be updated. (Bug #2996).
Fixed all bugs in scripts for creating/upgrading system database (Bug #2874) Added tests which guarantee against such bugs in the future.
Fixed bug in `mysql' command-line client in interpreting quotes within comments. (Bug #539)
--set-character-set and --character-sets-dir options in `myisamchk' now work.
Fixed a bug in mysqlbinlog that caused one pointer to be free'd twice in some cases.
Fixed a bug in boolean full-text search, that sometimes could lead to false matches in queries with several levels of subexpressions using + operator (for example, MATCH ... AGAINST('+(+(word1 word2)) +word3*' IN BOOLEAN MODE).
Fixed Windows-specific portability bugs in `myisam_ftdump'.
Fixed a bug in multiple-table DELETE that was caused by foreign key constraints. If the order of the tables established by MySQL optimizer did not match parent-child order, no rows were deleted and no error message was provided. (Bug #2799)
Fixed a few years old bug in the range optimizer that caused a segmentation fault on some very rare queries. (Bug #2698)
Replication: If a client connects to a slave server and issues an administrative statement for a table (for example, OPTIMIZE TABLE or REPAIR TABLE), this could sometimes stop the slave SQL thread. This does not lead to any corruption, but you must use START SLAVE to get replication going again. (Bug #1858) The bug was accidentally not fixed in 4.0.17 as it was unfortunately earlier said.
Fixed that when a Rotate event is found by the slave SQL thread in the middle of a transaction, the value of Relay_Log_Pos in SHOW SLAVE STATUS remains correct. (Bug #3017)
Corrected the master's binary log position that InnoDB reports when it is doing a crash recovery on a slave server. (Bug #3015)
Changed that when a DROP TEMPORARY TABLE statement is automatically written to the binary log when a session ends, the statement is recorded with an error code of value zero (this ensures that killing a SELECT on the master does not result in a superfluous error on the slave). (Bug #3063)
Changed that when a thread handling INSERT DELAYED (also known as a delayed_insert thread) is killed, its statements are recorded with an error code of value zero (killing such a thread does not endanger replication, so we thus avoid a superfluous error on the slave). (Bug #3081)
Fixed deadlock when two START SLAVE commands were run at the same time. (Bug #2921)
Fixed that a statement never triggers a superfluous error on the slave, if it must be excluded given the replicate-* options. The bug was that if the statement had been killed on the master, the slave would stop. (Bug #2983)
The --local-load option of mysqlbinlog now requires an argument.
Fixed a segmentation fault when running LOAD DATA FROM MASTER after RESET SLAVE. (Bug #2922)
Fixed a rare error condition that caused the slave SQL thread spuriously to print the message Binlog has bad magic number and stop when it was not necessary to do so. (Bug #3401)
Fixed the column Exec_master_log_pos (and its disk image in the relay-log.info file) to be correct if the master had version 3.23 (it was too big by 6 bytes). This bug does not exist in the 5.0 version. (Bug #3400)
Fixed that mysqlbinlog does not forget to print a USE command under rare circumstances where the binary log contained a LOAD DATA INFILE command. (Bug #3415)
Fixed a memory corruption when replicating a LOAD DATA INFILE when the master had version 3.23. Some smaller problems remain in this setup, See section 6.7 Replication Features and Known Problems. (Bug #3422)
Multiple-table DELETE statements were always replicated by the slave if there were some replicate-*-ignore-table options and no replicate-*-do-table options. (Bug #3461)

C.3.2 Changes in release 4.0.18 (12 Feb 2004)

Functionality added or changed:

Fixed processing of LOAD DATA by mysqlbinlog in remote mode. (Bug #1378)
New utility program `myisam_ftdump' was added to binary distributions.
ENGINE is now a synonym for the TYPE option for CREATE TABLE and ALTER TABLE.
lower_case_table_names system variable now can take a value of 2, to store table names in mixed case on case-insensitive filesystems. It's forced to 2 if the database directory is located on a case-insensitive filesystem.
For replication of MEMORY (HEAP) tables: Made the master automatically write a DELETE FROM statement to its binary log when a MEMORY table is opened for the first time since master's startup. This is for the case where the slave has replicated a non-empty MEMORY table, then the master is shut down and restarted: the table is now empty on master; the DELETE FROM empties it on slave too. Note that even with this fix, between the master's restart and the first use of the table on master, the slave still has out of date data in the table. But if you use the init-file option to populate the MEMORY table on the master at startup, it ensures that the failing time interval is zero. (Bug #2477)
Optimizer is now better tuned for the case where the first used key part (of many) is a constant. (Bug #1679)
Removed old non-working --old-rpl-compat server option, which was a holdover from the very first 4.0.x versions. (Bug #2428)

Bugs fixed:

mysqlhotcopy now works on NetWare.
DROP DATABASE could not drop databases with RAID tables that had more than nine RAID_CHUNKS. (Bug #2627)
Fixed bug in range optimizer when using overlapping ranges. (Bug #2448)
Limit wait_timeout to 2147483 on Windows (OS limit). (Bug #2400)
Fixed bug when --init-file crashes MySQL if it contains a large SELECT. (Bug #2526)
SHOW KEYS now shows NULL in the Sub_part column for FULLTEXT indexes.
The signal thread's stack size was increased to enable mysqld to run on Debian/IA-64 with a TLS-enabled glibc. (Bug #2599)
Now only the SELECT privilege is needed for tables that are only read in multiple-table UPDATE statements. (Bug #2377)
Give proper error message if one uses LOCK TABLES ... ; INSERT ... SELECT and one used the same table in the INSERT and SELECT part. (Bug #2296)
SELECT INTO ... DUMPFILE now deletes the generated file on error.
Fixed foreign key reference handling to allow references to column names that contain spaces. (Bug #1725)
Fixed problem with index reads on character columns with BDB tables. The symptom was that data could be returned in the wrong lettercase. (Bug #2509)
Fixed a spurious table corruption problem that could sometimes appear on tables with indexed TEXT columns if these columns happened to contain values having trailing spaces. This bug was introduced in 4.0.17.
Fixed a problem where some queries could hang if a condition like indexed_TEXT_column = expr was present and the column contained values having trailing spaces. This bug was introduced in 4.0.17.
Fixed a bug that could cause incorrect results from a query that involved range conditions on indexed TEXT columns that happened to contain values having trailing spaces. This bug was introduced in 4.0.17. (Bug #2295)
Fixed incorrect path names in some of the manual pages. (Bug #2270)
Fixed spurious ``table corrupted'' errors in parallel repair operations. See section 5.2.3 Server System Variables.
Fixed a crashing bug in parallel repair operations. See section 5.2.3 Server System Variables.
Fixed bug in updating MyISAM tables for BLOB values longer than 16MB. (Bug #2159)
Fixed bug in mysqld_safe when running multiple instances of MySQL. (Bug #2114)
Fixed a bug in using HANDLER statement with tables not from a current database. (Bug #2304)
Fixed a crashing bug that occurred due to the fact that multiple-table UPDATE statements did not check that there was only one table to be updated. (Bug #2103)
Fixed a crashing bug that occurred due to BLOB column type index size being calculated incorrectly in MIN() and MAX() optimizations. (Bug #2189)
Fixed a bug with incorrect syntax for LOCK TABLES in mysqldump. (Bug #2242)
Fixed a bug in mysqld_safe that caused mysqld to generate a warning about duplicate user=xxx options if this option was specified in the [mysqld] or [server] sections of `my.cnf'. (Bug #2163)
INSERT DELAYED ... SELECT ... could cause table corruption because tables were not locked properly. This is now fixed by ignoring DELAYED in this context. (Bug #1983)
Replication: Sometimes the master gets a non-fatal error during the execution of a statement that does not immediately succeed. (For example, a write to a MyISAM table may first receive ``no space left on device,'' but later complete when disk space becomes available. See section A.4.3 How MySQL Handles a Full Disk.) The bug was that the master forgot to reset the error code to 0 after success, so the error code got into its binary log, thus causing the slave to issue false alarms such as ``did not get the same error as on master.'' (Bug #2083)
Removed a misleading ``check permissions on master.info'' from a replication error message, because the cause of the problem could be something other than permissions. (Bug #2121)
Fixed a crash when the replication slave was unable to create the first relay log. (Bug #2145)
Replication of LOAD DATA INFILE for an empty file from a 3.23 master to a 4.0 slave caused the slave to print an error. (Bug #2452)
When automatically forcing lower_case_table_names to 1 if the file system was case insensitive, mysqld could crash. This bug existed only in MySQL 4.0.17. (Bug #2481)
Restored ability to specify default values for TIMESTAMP columns that was erroneously disabled in previous release. (Bug #2539) Fixed SHOW CREATE TABLE to reflect these values. (Bug #1885) Note that because of the auto-update feature for the first TIMESTAMP column in a table, it makes no sense to specify a default value for the column. Any such default will be silently ignored (unless another TIMESTAMP column is added before this one). Also fixed the meaning of the DEFAULT keyword when it is used to specify the value to be inserted into a TIMESTAMP column other than the first. (Bug #2464)
Fixed bug for out-of-range arguments on QNX platform that caused UNIX_TIMESTAMP() to produce incorrect results or that caused non-zero values to be inserted into TIMESTAMP columns. (Bug #2523) Also, current time zone now is taken into account when checking if datetime values satisfy both range boundaries for TIMESTAMP columns. The range allowed for a TIMESTAMP column is time zone-dependant and equivalent to a range of 1970-01-01 00:00:01 UTC to 2037-12-31 23:59:59 UTC.
Multiple-table DELETE statements were never replicated by the slave if there were any replicate-*-table options. (Bug #2527)
Changes to session counterparts of variables query_prealloc_size, query_alloc_block_size, trans_prealloc_size, trans_alloc_block_size now have an effect. (Bug #1948)
Fixed bug in ALTER TABLE RENAME, when rename to the table with the same name in another database silently dropped destination table if it existed. (Bug #2628)

C.3.3 Changes in release 4.0.17 (14 Dec 2003)

Functionality added or changed:

mysqldump no longer dumps data for MERGE tables. (Bug #1846)
lower_case_table_names is now forced to 1 if the database directory is located on a case-insensitive filesystem. (Bug #1812)
Symlink creation is now disabled on systems where realpath() doesn't work. (Before one could use CREATE TABLE .. DATA DIRECTORY=.. even if HAVE_BROKEN_REALPATH was defined. This is now disabled to avoid problems when running ALTER TABLE).
Inserting a negative AUTO_INCREMENT value in a MyISAM table no longer updates the AUTO_INCREMENT counter to a big unsigned value. (Bug #1366)
Added four new modes to WEEK(..., mode) function. See section 13.5 Date and Time Functions. (Bug #1178)
Allow UNION DISTINCT syntax.
mysql_server_init() now returns 1 if it can't initialize the environment. (Previously mysql_server_init() called exit(1) if it could not create a key with pthread_key_create(). (Bug #2062)
Allow spaces in Windows service names.
Changed the default Windows service name for mysqld from MySql to MySQL. This should not affect usage, because service names are not case sensitive.
When you install mysqld as a service on Windows systems, mysqld will read startup options in option files from the option group with the same name as the service name. (Except when the service name is MySQL).

Bugs fixed:

Sending SIGHUP to mysqld crashed the server if it was running with --log-bin. (Bug #2045)
One can now configure MySQL as a Windows service as a normal user. (Bug #1802). Thanks to Richard Hansen for fixing this.
Database names are now compared in lowercase in ON clauses when lower_case_table_names is set. (Bug #1736)
IGNORE ... LINES option to LOAD DATA INFILE didn't work when used with fixed length rows. (Bug #1704)
Fixed problem with UNIX_TIMESTAMP() for timestamps close to 0. (Bug #1998)
Fixed problem with character values greater than 128 in the QUOTE() function. (Bug #1868)
Fixed searching of TEXT with endspace. (Bug #1651)
Fixed caching bug in multiple-table updates where same table was used twice. (Bug #1711)
Fixed directory permissions for the MySQL-server RPM documentation directory. (Bug #1672)
Fixed server crash when updating an ENUM column that is set to the empty string (for example, with REPLACE()). (Bug #2023)
mysql client program now correctly prints connection identifier returned by mysql_thread_id() as unsigned integer rather than as signed integer. (Bug #1951)
FOUND_ROWS() could return incorrect number of rows after a query with an impossible WHERE condition. (Bug #1468)
SHOW DATABASES no longer shows .sym files (on Windows) that do not point to a valid directory. (Bug #1385)
Fixed a possible memory leak on Mac OS X when using the shared libmysql.so library. (from pthread_key_create()). (Bug #2061)
Fixed bug in UNION statement with alias *. (Bug #1249)
Fixed a bug in DELETE ... ORDER BY ... LIMIT where the rows where not deleted in the proper order. (Bug #1024, Bug #1697).
Fixed serious problem with multi-threaded programs on Windows that used the embedded MySQL libraries. (Locks of tables were not handled correctly between different threads).
Code cleanup: Fixed a few code defects (potential memory leaks, null pointer dereferences, uninitialized variables). Thanks to Reasoning Inc. for informing us about these findings.
Fixed a buffer overflow error that occurred with prepended `0' characters in some columns of type DECIMAL. (Bug #2128)
Filesort was never shown in EXPLAIN if query contained an ORDER BY NULL clause. (Bug #1335)
Fixed invalidation of whole query cache on DROP DATABASE. (Bug #1898)
Fixed bug in range optimizer that caused wrong results for some unlikely AND/OR queries. (Bug #1828)
Fixed a crash in ORDER BY when ordering by expression and identifier. (Bug #1945)
Fixed a crash in an open HANDLER when an ALTER TABLE was executed in a different connection. (Bug #1826)
Fixed a bug in trunc* operator of full-text search which sometimes caused MySQL not to find all matched rows.
Fixed bug in prepending `0' characters to DECIMAL column values.
Fixed optimizer bug, introduced in 4.0.16, when REF access plan was preferred to more efficient RANGE on another column.
Fixed problem when installing a MySQL server as a Windows service using a command of the form mysqld --install mysql --defaults-file=path-to-file. (Bug #1643)
Fixed an incorrect result from a query that uses only const tables (such as one-row tables) and non-constant expression (such as RAND()). (Bug #1271)
Fixed bug when the optimizer did not take SQL_CALC_FOUND_ROWS into account if LIMIT clause was present. (Bug #1274)
mysqlbinlog now asks for a password at the console when the -p or --password option is used with no argument. This is consistent with the way that other clients such mysqladmin and mysqldump already behave. Note: A consequence of this change is that it is no longer possible to invoke mysqlbinlog as mysqlbinlog -p pass_val (with a space between the -p option and the following password value). (Bug #1595)
Fixed bug accidentally introduced in 4.0.16 where the slave SQL thread deleted its replicated temporary tables when STOP SLAVE was issued.
In a ``chain'' replication setup A->B->C, if 2 sessions on A updated temporary tables of the same name at the same time, the binary log of B became incorrect, resulting in C becoming confused. (Bug #1686)
In a ``chain'' replication setup A->B->C, if STOP SLAVE was issued on B while it was replicating a temporary table from A, then when START SLAVE was issued on B, the binary log of B became incorrect, resulting in C becoming confused. (Bug #1240)
When MASTER_LOG_FILE and MASTER_LOG_POS were not specified, CHANGE MASTER used the coordinates of the slave I/O thread to set up replication, which broke replication if the slave SQL thread lagged behind the slave I/O thread. This caused the slave SQL thread to lose some events. The new behavior is to use the coordinates of the slave SQL thread instead. See section 14.6.2.1 CHANGE MASTER TO Syntax. (Bug #1870)
Now if integer is stored or converted to TIMESTAMP or DATETIME value checks of year, month, day, hour, minute and second ranges are performed and numbers representing illegal timestamps are converted to 0 value. This behavior is consistent with manual and with behavior of string to TIMESTAMP/DATETIME conversion. (Bug #1448)
Fixed bug when BIT_AND() and BIT_OR() group functions returned incorrect value if SELECT used a temporary table and no rows were found. (Bug #1790).
BIT_AND() is now unsigned in all contexts. This means that it will now return 18446744073709551615 (= 0xffffffffffffffff) instead of -1 if there were no rows in the result.
Fixed bug with BIT_AND() still returning signed value for an empty set in some cases. (Bug #1972)
Fixed bug with ^ (XOR) and >> (bit shift) still returning signed value in some cases. (Bug #1993)
Replication: a rare race condition in the slave SQL thread, which could lead to a wrong complain that the relay log is corrupted. (Bug #2011)
Replication: in the slave SQL thread, a multiple-table UPDATE could produce a wrong complain that some record was not found in one table, if the UPDATE was preceded by a INSERT ... SELECT. (Bug #1701)
Fixed deficiency in MySQL code which is responsible for scanning directories. This deficiency caused SHOW TABLE STATUS to be very slow when a database contained a large number of tables, even if a single particular table were specified. (Bug #1952)

C.3.4 Changes in release 4.0.16 (17 Oct 2003)

Functionality added or changed:

Option values in option files now may be quoted. This is useful for values that contain whitespace or comment characters.
Write memory allocation information to error log when doing mysqladmin debug. This works only on systems that support the mallinfo() call (like newer Linux systems).
Added the following new server variables to allow more precise memory allocation: range_alloc_block_size, query_alloc_block_size, query_prealloc_size, transaction_alloc_block_size, and transaction_prealloc_size.
mysqlbinlog now reads option files. To make this work, you must now specify --read-from-remote-server when reading binary logs from a MySQL server. (Note that using a remote server is deprecated and may disappear in future mysqlbinlog versions).
Block SIGPIPE signals also for non-threaded programs. The blocking is moved from mysql_init() to mysql_server_init(), which is automatically called on the first call to mysql_init().
Added --libs_r and --include options to mysql_config.
New `> prompt for mysql. This prompt is similar to the '> and "> prompts, but indicates that an identifier quoted with backticks was begun on an earlier line and the closing backtick has not yet been seen.
Updated mysql_install_db to be able to use the local machine's IP address instead of the hostname when building the initial grant tables if skip-name-resolve has been specified. This option can be helpful on FreeBSD to avoid thread-safety problems with the FreeBSD resolver libraries. (Thanks to Jeremy Zawodny for the patch.)
A documentation change: Added a note that when backing up a slave, it is necessary also to back up the `master.info' and `relay-log.info' files, as well as any `SQL_LOAD-*' files located in the directory specified by the --slave-load-tmpdir option. All these files are needed when the slave resumes replication after you restore the slave's data.

Bugs fixed:

Fixed a spurious error ERROR 14: Can't change size of file (Errcode: 2) on Windows in DELETE FROM tbl_name without a WHERE clause or TRUNCATE TABLE tbl_name, when tbl_name is a MyISAM table. (Bug #1397)
Fixed a bug that resulted in thr_alarm queue is full warnings after increasing the max_connections variable with SET GLOBAL. (Bug #1435)
Made LOCK TABLES to work when Lock_tables_priv is granted on the database level and Select_priv is granted on the table level.
Fixed crash of FLUSH QUERY CACHE on queries that use same table several times (Bug #988).
Fixed core dump bug when setting an enum system variable (such as SQL_WARNINGS) to NULL.
Extended the default timeout value for Windows clients from 30 seconds to 1 year. (The timeout that was added in MySQL 4.0.15 was way too short). This fixes a bug that caused ERROR 2013: Lost connection to MySQL server during query for queries that lasted longer than 30 seconds, if the client didn't specify a limit with mysql_options(). Users of 4.0.15 on Windows should upgrade to avoid this problem.
More ``out of memory'' checking in range optimizer.
Fixed and documented a problem when setting and using a user variable within the same SELECT statement. (Bug #1194).
Fixed bug in overrun check for BLOB values with compressed tables. This was a bug introduced in 4.0.14. It caused MySQL to regard some correct tables containing BLOB values as corrupted. (Bug #770, Bug #1304, and maybe Bug #1295)
SHOW GRANTS showed USAGE instead of the real column-level privileges when no table-level privileges were given.
When copying a database from the master, LOAD DATA FROM MASTER dropped the corresponding database on the slave, thus erroneously dropping tables that had no counterpart on the master and tables that may have been excluded from replication using replicate-*-table rules. Now LOAD DATA FROM MASTER no longer drops the database. Instead, it drops only the tables that have a counterpart on the master and that match the replicate-*-table rules. replicate-*-db rules can still be used to include or exclude a database as a whole from LOAD DATA FROM MASTER. A database will also be included or excluded as a whole if there are some rules like replicate-wild-do-table=db1.% or replicate-wild-ignore-table=db1.%, as is already the case for CREATE DATABASE and DROP DATABASE in replication. (Bug #1248)
Fixed a bug where mysqlbinlog crashed with a segmentation fault when used with the -h or --host option. (Bug #1258)
Fixed a bug where mysqlbinlog crashed with a segmentation fault when used on a binary log containing only final events for LOAD DATA. (Bug #1340)
mysqlbinlog will not reuse temporary file names from previous runs. Previously mysqlbinlog failed if was used several times on the same binary log file that contained a LOAD DATA command.
Fixed compilation problem when compiling with OpenSSL 0.9.7 with disabled old DES support (If OPENSSL_DISABLE_OLD_DES_SUPPORT option was enabled).
Fixed a bug when two (or more) MySQL servers were running on the same machine, and they were both slaves, and at least one of them was replicating some LOAD DATA INFILE command from its master. The bug was that one slave MySQL server sometimes deleted the `SQL_LOAD-*' files (used for replication of LOAD DATA INFILE and located in the slave-load-tmpdir directory, which defaults to tmpdir) belonging to the other slave MySQL server of this machine, if these slaves had the same slave-load-tmpdir directory. When that happened, the other slave could not replicate LOAD DATA INFILE and complained about not being able to open some SQL_LOAD-* file. (Bug #1357)
If LOAD DATA INFILE failed for a small file, the master forgot to write a marker (a Delete_file event) in its binary log, so the slave could not delete 2 files (`SQL_LOAD-*.info' and `SQL_LOAD-*.data' from its tmpdir. (Bug #1391)
On Windows, the slave forgot to delete a SQL_LOAD-*.info file from tmpdir after successfully replicating a LOAD DATA INFILE command. (Bug #1392)
When a connection terminates, MySQL writes DROP TEMPORARY TABLE statements to the binary log for all temporary tables which the connection had not explicitly dropped. MySQL forgot to backquote the database and table names in the statement. (Bug #1345)
On some 64-bit machines (some HP-UX and Solaris machines), a slave installed with the 64-bit MySQL binary could not connect to its master (it connected to itself instead). (Bug #1256, Bug #1381)
Code was introduced in MySQL 4.0.15 for the slave to detect that the master had died while writing a transaction to its binary log. This code reported an error in a legal situation: When the slave I/O thread was stopped while copying a transaction to the relay log, the slave SQL thread would later pretend that it found an unfinished transaction. (Bug #1475)

C.3.5 Changes in release 4.0.15 (03 Sep 2003)

IMPORTANT:

If you are using this release on Windows, you should upgrade at least your clients (any program that uses libmysql.lib) to 4.0.16 or above. This is because the 4.0.15 release had a bug in the Windows client library that causes Windows clients using the library to die with a Lost connection to MySQL server during query error for queries that take more than 30 seconds. This problem is specific to Windows; clients on other platforms are unaffected.

Functionality added or changed:

mysqldump now correctly quotes all identifiers when communicating with the server. This assures that during the dump process, mysqldump will never send queries to the server that result in a syntax error. This problem is not related to the mysqldump program's output, which was not changed. (Bug #1148)
Change result set metadata information so that MIN() and MAX() report that they can return NULL (this is true because an empty set will return NULL). (Bug #324)
Produce an error message on Windows if a second mysqld server is started on the same TCP/IP port as an already running mysqld server.
The mysqld server variables wait_timeout, net_read_timeout, and net_write_timeout now work on Windows. One can now also set timeouts for read and writes in Windows clients with mysql_options().
Added option --sql-mode=NO_DIR_IN_CREATE to make it possible for slaves to ignore INDEX DIRECTORY and DATA DIRECTORY options given to CREATE TABLE. When this is mode is on, SHOW CREATE TABLE will not show the given directories.
SHOW CREATE TABLE now shows the INDEX DIRECTORY and DATA DIRECTORY options, if they were specified when the table was created.
The open_files_limit server variable now shows the real open files limit.
MATCH ... AGAINST() in natural language mode now treats words that are present in more than 2,000,000 rows as stopwords.
The Mac OS X installation disk images now include an additional `MySQLStartupItem.pkg' package that enables the automatic startup of MySQL on system startup. See section 2.2.3 Installing MySQL on Mac OS X.
Most of the documentation included in the binary tarball distributions (.tar.gz) has been moved into a subdirectory docs. See section 2.1.8 Installation Layouts.
The manual is now included as an additional info file in the binary distributions. (Bug #1019)
The binary distributions now include the embedded server library (libmysqld.a) by default. Due to a linking problem with non-gcc compilers, it was not included in all packages of the initial 4.0.15 release. The affected packages were rebuilt and released as 4.0.15a. See section 1.5.1.2 The Embedded MySQL Server.
MySQL can now use range optimization for BETWEEN with non-constant limits. (Bug #991)
Replication error messages now include the default database, so that users can check which database the failing query was run for.
A documentation change: Added a paragraph about how the binlog-do-db and binlog-ignore-db options are tested against the database on the master (see section 5.8.4 The Binary Log), and a paragraph about how replicate-do-db, replicate-do-table and analogous options are tested against the database and tables on the slave (see section 6.8 Replication Startup Options).
Now the slave does not replicate SET PASSWORD if it is configured to exclude the mysql database from replication (using for example replicate-wild-ignore-table=mysql.%). This was already the case for GRANT and REVOKE since version 4.0.13 (though there was Bug #980 in 4.0.13 & 4.0.14, which has been fixed in 4.0.15).
Rewrote the information shown in the State column of SHOW PROCESSLIST for replication threads and for MASTER_POS_WAIT() and added the most common states for these threads to the documentation, see section 6.3 Replication Implementation Details.
Added a test in replication to detect the case where the master died in the middle of writing a transaction to the binary log; such unfinished transactions now trigger an error message on the slave.
A GRANT command that creates an anonymous user (that is, an account with an empty username) no longer requires FLUSH PRIVILEGES for the account to be recognized by the server. (Bug #473)
CHANGE MASTER now flushes `relay-log.info'. Previously this was deferred to the next run of START SLAVE, so if mysqld was shutdown on the slave after CHANGE MASTER without having run START SLAVE, the relay log's name and position were lost. At restart they were reloaded from `relay-log.info', thus reverting to their old (incorrect) values from before CHANGE MASTER and leading to error messages (as the old relay log did not exist any more) and the slave threads refusing to start. (Bug #858)

Bugs fixed:

Fixed buffer overflow in password handling which could potentially be exploited by MySQL users with ALTER privilege on the mysql.user table to execute random code or to gain shell access with the UID of the mysqld process (thanks to Jedi/Sector One for spotting and reporting this bug).
Fixed server crash on FORCE INDEX in a query that contained "Range checked for each record" in the EXPLAIN output. (Bug #1172)
Fixed table/column grant handling - proper sort order (from most specific to less specific, see section 5.4.6 Access Control, Stage 2: Request Verification) was not honored. (Bug #928)
Fixed rare bug in MYISAM introduced in 4.0.3 where the index file header was not updated directly after an UPDATE of split dynamic rows. The symptom was that the table had a corrupted delete-link if mysqld was shut down or the table was checked directly after the update.
Fixed Can't unlock file error when running myisamchk --sort-index on Windows. (Bug #1119)
Fixed possible deadlock when changing key_buffer_size while the key cache was actively used. (Bug #1088)
Fixed overflow bug in MyISAM and ISAM when a row is updated in a table with a large number of columns and at least one BLOB/TEXT column.
Fixed incorrect result when doing UNION and LIMIT #,# when braces were not used around the SELECT parts.
Fixed incorrect result when doing UNION and ORDER BY .. LIMIT # when one didn't use braces around the SELECT parts.
Fixed problem with SELECT SQL_CALC_FOUND_ROWS ... UNION ALL ... LIMIT # where FOUND_ROWS() returned incorrect number of rows.
Fixed unlikely stack bug when having a BIG expression of type 1+1-1+1-1... in certain combinations. (Bug #871)
Fixed the bug that sometimes prevented a table with a FULLTEXT index from being marked as "analyzed".
Fixed MySQL so that the column length (in C API) for the second column in SHOW CREATE TABLE is always larger than the data length. The only known application that was affected by the old behavior was Borland dbExpress, which truncated the output from the command. (Bug #1064)
Fixed crash in comparisons of strings using the tis620 character set. (Bug #1116)
Fixed ISAM bug in MAX() optimization.
myisamchk --sort-records=N no longer marks table as crashed if sorting failed because of an inappropriate key. (Bug #892)
Fixed a minor bug in MyISAM compressed table handling that sometimes made it impossible to repair compressed table in "Repair by sort" mode. "Repair with keycache" (myisamchk --safe-recover) worked, though. (Bug #1015)
Fixed bug in propagating the version number to the manual included in the distribution files. (Bug #1020)
Fixed key sorting problem (a PRIMARY key declared for a column that is not explicitly marked NOT NULL was sorted after a UNIQUE key for a NOT NULL column).
Fixed the result of INTERVAL when applied to a DATE value. (Bug #792)
Fixed compiling of the embedded server library in the RPM spec file. (Bug #959)
Added some missing files to the RPM spec file and fixed some RPM building errors that occurred on Red Hat Linux 9. (Bug #998)
Fixed incorrect XOR evaluation in WHERE clause. (Bug #992)
Fixed bug with processing in query cache merged tables constructed from more then 255 tables. (Bug #930)
Fixed incorrect results from outer join query (e.g. LEFT JOIN) when ON condition is always false, and range search in used. (Bug #926)
Fixed a bug causing incorrect results from MATCH ... AGAINST() in some joins. (Bug #942)
MERGE tables do not ignore "Using index" (from EXPLAIN output) anymore.
Fixed a bug that prevented an empty table from being marked as "analyzed". (Bug #937)
Fixed myisamchk --sort-records crash when used on compressed table.
Fixed slow (as compared to 3.23) ALTER TABLE and related commands such as CREATE INDEX. (Bug #712)
Fixed segmentation fault resulting from LOAD DATA FROM MASTER when the master was running without the --log-bin option. (Bug #934)
Fixed a security bug: A server compiled without SSL support still allowed connections by users that had the REQUIRE SSL option specified for their accounts.
Fixed a random bug: Sometimes the slave would replicate GRANT or REVOKE queries even if it was configured to exclude the mysql database from replication (for example, using replicate-wild-ignore-table=mysql.%). (Bug #980)
The Last_Errno and Last_Error fields in the output of SHOW SLAVE STATUS are now cleared by CHANGE MASTER and when the slave SQL thread starts. (Bug #986)
A documentation mistake: It said that RESET SLAVE does not change connection information (master host, port, user, and password), whereas it does. The statement resets these to the startup options (master-host etc) if there were some. (Bug #985)
SHOW SLAVE STATUS now shows correct information (master host, port, user, and password) after RESET SLAVE (that is, it shows the new values, which are copied from the startup options if there were some). (Bug #985)
Disabled propagation of the original master's log position for events because this caused unexpected values for Exec_Master_Log_Pos<