Performance: The query cache now checks whether a SELECT statement begins with SQL_NO_CACHE to determine whether it can skip checking for the query result in the query cache. This is not supported when SQL_NO_CACHE occurs within a comment. (Bug#37416)

mysql-test-run.pl now supports an --experimental=file_name option. It enables you to specify a file that contains a list of test cases that should be displayed with the [ exp-fail ] code rather than [ fail ] if they fail. (Bug#42888)

The MD5 algorithm now uses the Xfree implementation. (Bug#42434)

Partitioning: A duplicate key error raised when inserting into a partitioned table used a different error code from that returned by such an error raised when inserting into a table that was not partitioned. (Bug#38719)

See also Bug#28842.

Partitioning: Several error messages relating to partitioned tables were incorrect or missing. (Bug#36001)

Replication: When --binlog_format was set to STATEMENT, a statement unsafe for statement-based logging caused an error or warning to be issued even if sql_log_bin was set to 0. (Bug#41980)

Replication: When using MIXED replication format and temporary tables were created in statement-based mode, but a later operation in the same session caused a switch to row-based mode, the temporary tables were not dropped on the slave at the end of the session. (Bug#40013)

See also Bug#43046.

This regression was introduced by Bug#20499.

Replication: When using the MIXED replication format, UPDATE and DELETE statements that searched for rows where part of the key had nullable BIT columns failed. This occurred because operations that inserted the data were replicated as statements, but UPDATE and DELETE statements affecting the same data were replicated using row-based format.

This issue did not occur when using statement-based replication (only) or row-based replication (only). (Bug#39753)

See also Bug#39648.

Replication: The server SQL mode in effect when a stored procedure was created was not retained in the binary log. This could cause a CREATE PROCEDURE statement that succeeded on the master to fail on the slave.

This issue was first noticed when a stored procedure was created when ANSI_QUOTES was in effect on the master, but could possibly cause failed CREATE PROCEDURE statements and other problems on the slave when using other server SQL modes as well. (Bug#39526)

Replication: If --secure-file-priv was set on the slave, it was unable to execute LOAD DATA INFILE statements sent from the master when using mixed-format or statement-based replication.

As a result of this fix, this security restriction is now ignored on the slave in such cases; instead the slave checks whether the files were created and should be read by the slave in its --slave-load-tmpdir. (Bug#38174)

Replication: Server IDs greater than 2147483647 (2³² – 1) were represented by negative numbers in the binary log. (Bug#37313)

Replication: When its disk becomes full, a replication slave may wait while writing the binary log, relay log or MyISAM tables, continuing after space has been made available. The error message provided in such cases was not clear about the frequency with which checking for free space is done (once every 60 seconds), and how long the server waits after space has been freed before continuing (also 60 seconds); this caused users to think that the server had hung.

These issues have been addressed by making the error message clearer, and dividing it into two separate messages:

(Bug#22082)

Replication: The statements DROP PROCEDURE IF EXISTS and DROP FUNCTION IF EXISTS were not written to the binary log if the procedure or function to be dropped did not exist. (Bug#13684)

See also Bug#25705.

The IBM DB2i storage engine has been added to this release for the IBM i Series platform. For more information, see The IBMDB2I Storage Engine. (Bug#44217)

On 64-bit debug builds, code in safemalloc resulted in errors due to use of a 32-bit value for 64-bit allocations. (Bug#43885)

make distcheck failed to properly handle subdirectories of storage/ndb. (Bug#43614)

Use of USE INDEX hints could cause EXPLAIN EXTENDED to crash. (Bug#43354)

For InnoDB tables, overflow in an AUTO_INCREMENT column could cause a server crash. (Bug#43203)

On 32-bit Windows, mysqld could not use large buffers due to a 2GB user mode address limit. (Bug#43082)

stderr should be unbuffered, but when the server redirected stderr to a file, it became buffered. (Bug#42790)

The DATA_TYPE column of the INFORMATION_SCHEMA.COLUMNS table displayed the UNSIGNED attribute for floating-point data types. (The column should contain only the data type name.) (Bug#42758)

For InnoDB tables, spurious duplicate-key errors could occur when inserting into an AUTO_INCREMENT column. (Bug#42714)

mysqldump included views that were excluded with the --ignore-table option. (Bug#42635)

An earlier bug fix resulted in the problem that the InnoDB plugin could not be used with a server that was compiled with the built-in InnoDB. To handle this two changes were made:

(Bug#42610)

This regression was introduced by Bug#29263.

With the ONLY_FULL_GROUP_BY SQL mode enabled, some legal queries failed. (Bug#42567)

Tables could enter open table cache for a thread without being properly cleaned up, leading to a server crash. (Bug#42419)

For InnoDB tables, inserting into floating-point AUTO_INCREMENT columns failed. (Bug#42400)

The InnoDB btr_search_drop_page_hash_when_freed() function had a race condition. (Bug#42279)

For InnoDB tables, there was a race condition for ALTER TABLE, OPTIMIZE TABLE, CREATE INDEX, and DROP INDEX operations when periodically checking whether table copying can be committed. (Bug#42152)

Parsing of the optional microsecond component of DATETIME values did not fail gracefully when that component width was larger than the allowed six places. (Bug#42146)

In InnoDB recovery after a server crash, table lookup could fail and corrupt the data dictionary cache. (Bug#42075)

mysqldumpslow parsed the --debug and --verbose options incorrectly. (Bug#42027)

Queries that used the loose index scan access method could return no rows. (Bug#41610)

In InnoDB recovery after a server crash, rollback of a transaction that updated a column from NULL to NULL could cause another crash. (Bug#41571)

The error message for a too-long column comment was Unknown error rather than a more appropriate message. (Bug#41465)

Use of SELECT * allowed users with rights to only some columns of a view to access all columns. (Bug#41354)

If the tables underlying a MERGE table had a primary key but the MERGE table itself did not, inserting a duplicate row into the MERGE table caused a server crash. (Bug#41305)

The server did not robustly handle problems hang if a table opened with HANDLER needed to be re-opened because it had been altered to use a different storage engine that does not support HANDLER. The server also failed to set an error if the re-open attempt failed. These problems could cause the server to crash or hang. (Bug#41110, Bug#41112)

SELECT statements executed concurrently with INSERT statements for a MyISAM table could cause incorrect results to be returned from the query cache. (Bug#41098)

For prepared statements, multibyte character sets were not taking into account when calculating max_length for string values and mysql_stmt_fetch() could return truncated strings. (Bug#41078)

Deprecation warnings that referred to MySQL 5.2 were changed to refer to MySQL 6.0. (Bug#41077)

For user-defined variables in a query result, incorrect length values were returned in the result metadata. (Bug#41030)

On Windows, starting the server with an invalid value for innodb_flush_method caused a crash. (Bug#40757)

MySQL 5.1 crashed with index merge algorithm and merge tables.

A query in the MyISAM merge table caused a crash if the index merge algorithm was being used. (Bug#40675)

With strict SQL mode enabled, setting a system variable to an out-of-bounds value caused an assertion failure. (Bug#40657)

Table temporary scans were slower than necessary due to use of mmap rather than caching, even with the myisam_use_mmap system variable disabled. (Bug#40634)

For a view that references a table in another database, mysqldump wrote the view name qualified with the current database name. This makes it impossible to reload the dump file into a different database. (Bug#40345)

On platforms where long and pointer variables have different sizes, MyISAM could copy key statistics incorrectly, resulting in a server crash or incorrect cardinality values. (Bug#40321)

DELETE tried to acquire write (not read) locks for tables accessed within a subquery of the WHERE clause. (Bug#39843)

perror did not produce correct output for error codes 153 to 163. (Bug#39370)

Several functions in libmysqld called exit() when an error occurred rather than returning an error to the caller. (Bug#39289)

The innodb_log_arch_dir system variable is no longer available but was present in some of the sample option files included with MySQL distributions (such as my-huge.cnf). The line was present as a comment but uncommenting it would cause server startup failure so the line has been removed. (Bug#38249)

Setting a savepoint with the same name as an existing savepoint incorrectly deleted any other savepoints that had been set in the meantime. For example, setting savepoints named a, b, c, b resulted in savepoints a, b, rather than the correct savepoints a, c, b. (Bug#38187)

--help output for myisamchk did not list the --HELP option. (Bug#38103)

Comparisons between row constructors, such as (a, b) = (c, d) resulted in unnecessary Illegal mix of collations errors for string columns. (Bug#37601)

If a user created a view that referenced tables for which the user had disjoint privileges, an assertion failure occurred. (Bug#37191)

An argument to the MATCH() function that was an alias for an expression other than a column name caused a server crash. (Bug#36737)

The event, general_log, and slow_log tables in the mysql database store server_id values, but did not use an UNSIGNED column and thus were not able to store the full range of ID values. (Bug#36540)

On Windows, the _PC macro in my_global.h was causing problems for modern compilers. It has been removed because it is no longer used. (Bug#34309)

For DROP FUNCTION with names that were qualified with a database name, the database name was handled in case-sensitive fashion even with lower_case_table_names set to 1. (Bug#33813)

mysqldump --compatible=mysql40 emitted statements referring to the character_set_client system variable, which is unknown before MySQL 4.1. Now the statements are enclosed in version-specific comments. (Bug#33550)

Detection by configure of several functions such as setsockopt(), bind(), sched_yield(), and gtty() could fail. (Bug#31506)

Use of MBR spatial functions such as MBRTouches() with columns of InnoDB tables caused a server crash rather than an error. (Bug#31435)

The mysql client mishandled input parsing if a delimiter command was not first on the line. (Bug#31060)

SHOW PRIVILEGES listed the CREATE ROUTINE privilege as having a context of Functions,Procedures, but it is a database-level privilege. (Bug#30305)

mysqld --help did not work as root. (Bug#30261)

CHECK TABLE, REPAIR TABLE, ANALYZE TABLE, and OPTIMIZE TABLE erroneously reported a table to be corrupt if the table did not exist or the statement was terminated with KILL. (Bug#29458)

SHOW TABLE STATUS could fail to produce output for tables with non-ASCII characters in their name. (Bug#25830)

Allocation of stack space for error messages could be too small on HP-UX, leading to stack overflow crashes. (Bug#21476)

Floating-point numbers could be handled with different numbers of digits depending on whether the text or prepared-statement protocol was used. (Bug#21205)

Incorrect length metadata could be returned for LONG TEXT columns when a multibyte server character set was used. (Bug#19829)

ROUND() sometimes returned different results on different platforms. (Bug#15936)