The deprecated mysql_fix_privilege_tables script has been removed. (Bug#42589)

All numeric operators and functions on integer, floating point and DECIMAL values now throw an “out of range” error (ER_DATA_OUT_OF_RANGE) rather than returning an incorrect value or NULL, when the result is out of the supported range for the corresponding data type. (Bug#8433)

Partitioning: Partition pruning on RANGE partitioned tables did not always work correctly; the last partition partition was not excluded if the range was beyond it (when not using MAXVALUE).Now the last partition is not included if the partitioning function value is not within the range. (Bug#51830)

Partitioning: Attempting to partition a table using a DECIMAL column caused the server to crash; this not supported and is now specifically disallowed. (Bug#51347)

Partitioning: The insert_id server system variable was not reset following an insert that failed on a partitioned MyISAM table having an AUTO_INCREMENT column. (Bug#50392)

Partitioning: Foreign keys are not supported on partitioned tables. However, it was possible via an ALTER TABLE statement to set a foreign key on a partitioned table; it was also possible to partition a table with a single foreign key. (Bug#50104)

Partitioning: GROUP BY queries performed poorly for some partitioned tables. This was due to the block size not being set for partitioned tables, thus the keys per block was not correct, which could cause such queries to be optimized incorrectly. (Bug#48229)

See also Bug#37252.

Replication: The flag stating whether a user value was signed or unsigned (unsigned_flag) could sometimes change between the time that the user value was recorded for logging purposes and the time that the value was actually written to the binary log, which could lead to inconsistency. Now unsigned_flag is copied when the user variable value is copied, and the copy of unsigned_flag is then used for logging. (Bug#51426)

See also Bug#49562.

Replication: TRUNCATE TABLE performed on a temporary table using the InnoDB storage engine was logged even when using row-based mode. (Bug#51251)

Replication: When using temporary tables the binary log needs to insert a pseudo-thread ID for threads that are using temporary tables, each time a switch happens between two threads, both of which are using temporary tables. However, if a thread issued a failing statement before exit, its ID was not recorded in the binary log, and this in turn caused the ID for the next thread that tried to do something with a temporary table not to be logged as well. Subsequent replays of the binary log failed with the error Table ... doesn't exist. (Bug#51226)

Replication: If the master was using sql_mode='TRADITIONAL', duplicate key errors were not sent to the slave, which received 0 rather than the expected error code. This caused replication to fail even when such an error was expected. (Bug#51055)

For LDML-defined collations, some data structures were not initialized properly to enable UPPER() and LOWER() to work correctly. (Bug#51976)

Invalid memory reads occurred for HANDLER ... READ NEXT after a failed HANDLER ... READ FIRST. (Bug#51877)

The optimizer performed an incorrect join type when COALESCE() appeared within an IN() operation. (Bug#51598)

With an XA transaction active, SET autocommit = 1 could cause side effects such as memory corruption or a server crash. (Bug#51342)

Following a bulk insert into a MyISAM table, if MyISAM failed to build indexes using repair by sort, data file corruption could occur. (Bug#51307)

CHECKSUM TABLE could compute the checksum for BIT columns incorrectly. (Bug#51304)

A HAVING clause on a joined table in some cases failed to eliminate rows which should have been excluded from the result set. (Bug#51242)

Two sessions trying to set the global event_scheduler system variable to different values could deadlock. (Bug#51160)

The type inference used for view columns caused some columns in views to be handled as the wrong type, as compared to the same columns in base tables. DATE columns in base tables were treated as TIME columns in views, and base table TIME columns as view DATETIME columns. (Bug#50918)

The YEAR values 2000 and 0000 could be treated as equal. (Bug#49910)

Performing a single in-place ALTER TABLE containing ADD INDEX and DROP INDEX options that used the same index name could result in a corrupt table definition file. Now such ALTER TABLE statements are no longer performed in place. (Bug#49838)

mysql_upgrade did not detect when CSV log tables incorrectly contained columns that could be NULL. Now these columns are altered to be NOT NULL. (Bug#49823)

The MERGE engine failed to open a child table from a different database if the child table or database name contained characters that were the subject of table name to filename encoding.

Further, the MERGE engine did not properly open a child table from the same database if the child table name contained characters such as '/', '#'. (Bug#48265)

The optimization to read MIN() or MAX() values from an index did not properly handle comparisons with NULL values. This could produce incorrect results for MIN() or MAX()when the WHERE clause tested a NOT NULL column for NULL. (Bug#47762)

Killing a query during the optimization phase of a subquery could cause a server crash. (Bug#47761)

The query shown by EXPLAIN EXTENDED plus SHOW WARNINGS could produce results different from the original query. (Bug#47669)

Setting myisam_repair_threads larger than 1 could result in the cardinality for all indexes of a MyISAM table being set to 1 after parallel index repair. (Bug#47444)

A query on a FEDERATED table in which the data was ordered by a TEXT column returned incorrect results. For example, a query such as the following would result in incorrect results if column column1 was a TEXT column:

SELECT * FROM table1 ORDER BY column1;

(Bug#32426)