MySQL Cluster: More informative error messages are provided when a query is issued against an NDB table that has been modified by another mysqld server. (Bug #6762)

InnoDB: When foreign_key_checks = 0, ALTER TABLE and RENAME TABLE will ignore any type incompatibilities between referencing and referenced columns. Thus, it will be possible to convert the character sets of columns that participate in a foreign key. Be sure to convert all tables before modifying any data! (Bug #9802)

The behavior controlled by the --innodb-fast-shutdown option now can be changed at runtime by setting the value of the global innodb_fast_shutdown system variable. It now accepts values 0, 1 and 2 (except on Netware where 2 is disabled). If set to 2, then when the MySQL server shuts down, InnoDB will just flush its logs and shut down brutally (and quickly) as if a MySQL crash had occurred; no committed transaction will be lost, but a crash recovery will be done at next startup.

Added support for the BIT data type to the MEMORY, InnoDB, and BDB storage engines.

SHOW VARIABLES no longer displays the deprecated log_update system variable. (Bug #9738)

Security Fix: Starting mysqld with --user=non_existent_user caused it to run using the privileges of the account from which it was invoked, including the root account. (Bug #9833)

Queries containing CURRENT_USER() incorrectly were registered in the query cache. (Bug #9796)

InnoDB: Assertion failures of types ut_a(cursor->old_stored == BTR_PCUR_OLD_STORED) and prebuilt->template_type == 0 could occur when performing multi-table updates. This bug was introduced in 4.1.10 and 4.0.24. (Bug #9670)

A problem with readlinecaused the mysql client to crash when the user pressed Control+R.. (Bug #9568)

Invoking a stored function that returned a value having an ENUM or SET data type caused the server to crash. (Bug #9775)

InnoDB: Next-key locking did not permit inserts which did not produce a “phantom”. If the range is of type 'a' <= uniquecolumn, InnoDB lock only the RECORD, if the record with the column value 'a' exists in a CLUSTERED index. This enables inserts before a range. (Bug #9354)

Corrected a failure to resolve a column reference correctly for a LEFT JOIN that compared a join column to an IN subquery. (Bug #9338)

InnoDB: Prevent ALTER TABLE from changing the storage engine if there are foreign key constraints on the table. (Bug #5574, Bug #5670)

The optimizer did not compute the union of two ranges for the OR operator correctly. (Bug #9348)

Setting the storage_engine system variable to MEMORY succeeded, but retrieving the variable resulted in a value of HEAP (the old name for the MEMORY storage engine) rather than MEMORY. (Bug #10039)

Use of a subquery that used WITH ROLLUP in the FROM clause of the main query sometimes resulted in a Column cannot be null error. (Bug #9681)

Selecting from a view containing a subquery caused the server to hang. (Bug #8490)

mysqlshow displayed an incorrect row count for tables. (Bug #9391)

Multiple-table updates could produce spurious data-truncation warnings if they used a join across columns that are indexed using a column prefix. (Bug #9103)

Invocation of a stored function that returned a value having a BIT data type caused the server to crash. (Bug #7648)

After an internal temporary table became too large in memory and had to be converted to an on-disk table, the error indicator was not cleared and the query failed with error 1023 Can't find record in ''. (Bug #9703)

For stored functions that should return a YEAR value, corrected a failure of the value to be in YEAR format. (Bug #8861)

Invocation of a stored function that returned a value having a BLOB data type caused the server to crash. (Bug #9102)

Executing LOCK TABLES and then calling a stored procedure caused an error and resulting in the server thinking that no stored procedures exist. (Bug #9566)

OPTIMIZE TABLE was written twice to the binary log when used on InnoDB tables. (Bug #9149)

SET @var= CAST(NULL AS [INTEGER|CHAR]) now sets the result type of the variable to INTEGER/CHAR. (Bug #6598)

Column references were not properly resolved when an outer join involving a view contained a subquery and the column was used both in the subquery and the outer query. (Bug #6107, Bug #6106)

The server died with signal 11 if a nonexistent location was specified for the location of the binary log. Now the server exits after printing an appropriate error message. (Bug #9542)

TIMEDIFF() with a negative time first argument and positive time second argument produced incorrect results. (Bug #8068)

A segmentation fault in mysqlcheck occurred when the last table checked in --auto-repair mode returned an error (such as the table being a MERGE table). (Bug #9492)

Incorrect results were returned for queries of the form SELECT ... LEFT JOIN ... WHERE EXISTS (subquery), where the subquery selected rows based on an IS NULL condition. (Bug #9516)

Within a stored procedure, attempting to execute a multiple-table UPDATE failed with a Table 'tbl_name' was locked with a READ lock and can't be updated error. (Bug #9486)

The client/server protocol permitted the server to close the connection before sending the final error message. The problem could show up as a Lost connection to MySQL server error during a query when attempting to connect and access a nonexistent database. (Bug #6387, Bug #9455)

A string length comparison problem caused mysql to fail when loading dump files containing certain escape sequences containing a backslash character (\). (Bug #9756)

A memory leak occurred when selecting from a view that contained a subquery. (Bug #10107)