Important Change: mysqlbinlog now supports --verbose and --base64-output=DECODE-ROWS options to display row events as commented SQL statements. (The default otherwise is to display row events encoded as base-64 strings using BINLOG statements.) See Section 4.6.7.2, “mysqlbinlog Row Event Display”. (Bug#31455)

Falcon builds on AMD64 platforms now. (Bug#38535)

mysqltest now installs signal handlers and generates a stack trace if it crashes. (Bug#37003)

A new system variable, backupdir, enables the default directory to be specified for BACKUP DATABASE and RESTORE operations when the image file pathname is not a full pathname. The default value for this variable is the data directory. (Bug#35230)

The mysql.online_backup and mysql.online_backup_progress tables now have a default character set of utf8 rather than latin1. (Bug#33836)

mysqltest was changed to be more robust in the case of a race condition that can occur for rapid disconnect/connect sequences with the server. The account used by mysqltest could reach its allowed simultaneous-sessions user limit if the connect attempt occurred before the server had fully processed the preceding disconnect. mysqltest now checks specificaly for a user-limits error when it connects; if that error occurs, it delays briefly before retrying. (Bug#23921)

Previously, BACKUP DATABASE did not back up privileges and RESTORE did not restore them. Now privileges for backed-up databases are saved. This includes privileges at the database level and below (table, column, routine). Global privileges are not saved. For additional information about how privileges are backed up, see Section 6.3.1, “Quick Guide to MySQL Backup”.

A new session system variable, backup_wait_timeout, controls the number of seconds a BACKUP DATABASE or RESTORE operation waits for a blocked DDL statements before aborting with an error.

The CREATE TABLESPACE privilege has been introduced. This privilege exists at the global (superuser) level and enables you to create, alter, and drop tablespaces and logfile groups.

Improvements made to MySQL Backup (the BACKUP DATABASE and RESTORE statements):

Security Enhancement: The server consumed excess memory while parsing statements with hundreds or thousands of nested boolean conditions (such as OR (OR ... (OR ... ))). This could lead to a server crash or incorrect statement execution, or cause other client statements to fail due to lack of memory. The latter result constitutes a denial of service. (Bug#38296)

Incompatible Change: There were some problems using DllMain() hook functions on Windows that automatically do global and per-thread initialization for libmysqld.dll:

To correct these problems, DLL initialization code now is not invoked from libmysql.dll by default. (Bug#37226, Bug#33031)

Incompatible Change: Some performance problems of SHOW ENGINE INNODB STATUS were reduced by removing used cells and Total number of lock structs in row lock hash table from the output. These values are now present only if UNIV_DEBUG is defined at MySQL build time. (Bug#36941, Bug#36942)

Important Change: The INFORMATION_SCHEMA.FALCON_TABLES table has been removed. (Bug#29211, Bug#34705, Bug#34706)

Partitioning: When a partitioned table had a TIMESTAMP column defined with CURRENT_TIMESTAMP as the default but with no ON UPDATE clause, the column's value was incorrectly set to CURRENT_TIMESTAMP when updating across partitions. (Bug#38272)

Partitioning: A LIST partitioned MyISAM table returned erroneous results when an index was present on a column in the WHERE clause and NOT IN was used on that column.

Searches using the index were also much slower then if the index were not present. (Bug#35931)

Partitioning: SELECT COUNT(*) was not correct for some partitioned tables using a storage engine that did not support HA_STATS_RECORDS_IS_EXACT. Tables using the ARCHIVE storage engine were known to be affected.

This was because ha_partition::records() was not implemented, and so the default handler::records() was used in its place. However, this is not correct behavior if the storage engine does not support HA_STATS_RECORDS_IS_EXACT.

The solution was to implement ha_partition::records() as a wrapper around the underlying partition records.

As a result of this fix, the rows column in the output of EXPLAIN PARTITIONS now includes the total number of records in the partitioned table. (Bug#35745)

Replication: Server code used in binary logging could in some cases be invoked even though binary logging was not actually enabled, leading to asserts and other server errors. (Bug#38798)

Replication: Row-based replication broke for utf8 CHAR columns longer than 85 characters. (Bug#37426)

Replication: When autocommit was set equal to 1 after starting a transaction, the binary log did not commit the outstanding transaction. The reason this happened was that the binary log commit function saw only the values of the new settings, and decided that there was nothing to commit.

This issue was first observed when using the Falcon storage engine, but it is possible that it affected other storage engines as well. (Bug#37221)

Replication: Some kinds of internal errors, such as Out of memory errors, could cause the server to crash when replicating statements with user variables.

certain internal errors. (Bug#37150)

Replication: Row-based replication did not correctly copy TIMESTAMP values from a big-endian storage engine to a little-endian storage engine. (Bug#37076)

Replication: Performing an insert on a table having an AUTO_INCREMENT column and an INSERT trigger that was being replicated from a master running MySQL 5.0 or any version of MySQL 5.1 up to and including MySQL 5.1.11 to a slave running MySQL 5.1.12 or later caused the replication slave to crash. (Bug#36443)

See also Bug#33029.

Hostname lookup failure could lead to a server crash. (Bug#39153)

When recovering from a serial log containing many CREATE TABLESPACE and DROP TABLESPACE statements, Falcon could lose data from tablespaces not referenced by these statements. (Bug#39138)

See also Bug#39789.

Falcon key pages were written to the serial log in the wrong order. This had the potential to cause problems if a failure of the server occurred during recovery. (Bug#39025)

Falcon could hang trying to perform an UPDATE in one transaction while waiting for another transaction to be committed or rolled back. (Bug#38947)

It was not possible to build the server with Falcon support on SPARC when using the Sun Studio compiler. (Bug#38891)

On Solaris platforms, when the server was built with Falcon support and the data directory set in user's home directory, mysql_install_db failed. (Bug#38843)

Falcon did not honor the --datadir option and created its files in the current directory instead. This error was apparent only when running the embedded version of MySQL. (Bug#38770)

When built with Falcon support on 64-bit SPARC platforms, mysqld hung on startup. This occurred whether Sun Studio or gcc was used to compile the server. (Bug#38766)

Falcon did not build on Linux with Valgrind enabled. (Bug#38746)

Server-side cursors were not initialized properly, which could cause a server crash. (Bug#38486)

A server crash or Valgrind warnings could result when a stored procedure selected from a view that referenced a function. (Bug#38291)

A failure to clean up binary log events was corrected (detected by Valgrind). (Bug#38290)

Queries containing a subquery with DISTINCT and ORDER BY could cause a server crash. (Bug#38191)

CREATE TABLESPACE failed when invoked immediately following a DROP TABLESPACE statement that used the same tablespace name. (Bug#38186, Bug#38743)

Over-aggressive lock acquisition by InnoDB when calculating free space for tablespaces could result in performance degradation when multiple threads were executing statements on multi-core machines. (Bug#38185)

The fix for Bug#20748 caused a problem such that on Unix, MySQL programs looked for options in ~/my.cnf rather than the standard location of ~/.my.cnf. (Bug#38180)

UUID() values could have hyphens in the wrong place. (Bug#38160)

Queries with a HAVING clause could return a spurious row. (Bug#38072)

MyISAM tables with non-ASCII characters in their names could not be backed up because the MyISAM native backup driver did not handle them properly. (Bug#38045)

Dropping and re-creating a Falcon table, then adding indexes to the re-created table, could cause spurious errors or possibly a crash of the server. (Bug#38039)

If the table definition cache contained tables with many BLOB columns, much memory could be allocated to caching BLOB values. Now a size limit on the cached BLOB values is enforced. (Bug#38002)

The server returned incorrect results for WHERE ... OR ... GROUP BY queries against InnoDB tables. (Bug#37977)

SUM(DISTINCT) and AVG(DISTINCT) for an empty result set in a subquery were not properly handled as being able to return NULL. (Bug#37891)

For InnoDB tables, ORDER BY ... DESC sometimes returned results in ascending order. (Bug#37830)

The server returned unexpected results if a right side of the NOT IN clause consisted of the NULL value and some constants of the same type. For example, this query might return 3, 4, 5, and so forth if a table contained those values:

SELECT * FROM t WHERE NOT t.id IN (NULL, 1, 2);

(Bug#37761)

Executing large numbers of SQL statements using LIMIT on Falcon tables eventually led to a crash of the server. (Bug#37726)

Setting the session value of the innodb_table_locks system variable caused a server crash. (Bug#37669)

Nesting of IF() inside of SUM() could cause an extreme server slowdown. (Bug#37662)

For BACKUP DATABASE, if the WITH COMPRESSION clause was not used, an uninitialized variable could cause unpredictable results. (Bug#37654)

Killing a query that used an EXISTS subquery as the argument to SUM() or AVG() caused a server crash. (Bug#37627)

mysqld failed to build using the Sun Studio compiler. (Bug#37603)

When using indexed ORDER BY sorting, incorrect query results could be produced if the optimizer switched from a covering index to a non-covering index. (Bug#37548)

After TRUNCATE TABLE for an InnoDB table, inserting explicit values into an AUTO_INCREMENT column could fail to increment the counter and result in a duplicate-key error for subsequent insertion of NULL. (Bug#37531)

For a MyISAM table with CHECKSUM = 1 and ROW_FORMAT = DYNAMIC table options, a data consistency check (maximum record length) could fail and cause the table to be marked as corrupted. (Bug#37310)

The max_length result set metadata value was calculated incorrectly under some circumstances. (Bug#37301)

The optimizer_switch system variable takes a comma-separated list of values, but only the first value in the list was used. (Bug#37120)

Executing ALTER TABLE ADD PARTITION followed by ALTER TABLE DROP PARTITION on a Falcon table, and then killing the thread performing these statements could cause the server to crash. (Bug#37072)

NOT IN subqueries that selected MIN() or MAX() values but produced an empty result could cause a server crash. (Bug#37004)

A server crash resulted from attempts at semi-join and materialization optimizations for subqueries with a parent of SELECT ... FROM DUAL. (Bug#36896)

Server crashed when starting a new BACKUP DATABASE or RESTORE statement while a BACKUP DATABASE or RESTORE was ongoing. (Bug#36795)

The CSV storage engine returned success even when it failed to open a table's data file. (Bug#36638)

SELECT DISTINCT from a simple view on an InnoDB table, where all selected columns belong to the same unique index key, returned incorrect results. (Bug#36632)

RESTORE could fail if the server on which the restore operation took place had enabled triggers or events. (Bug#36530)

The parser incorrectly allowed MySQL error code 0 to be specified for a condition handler. (This is incorrect because the condition must be a failure condition and 0 indicates success.) (Bug#36510)

CHAR(256 USING utf32) could generate a result with an incorrect length and result in a server crash. (Bug#36418)

If initialization of an INFORMATION_SCHEMA plugin failed, INSTALL PLUGIN freed some internal plugin data twice. (Bug#36399)

When the fractional part in a multiplication of DECIMAL values overflowed, the server truncated the first operand rather than the longest. Now the server truncates so as to produce more precise multiplications. (Bug#36270)

The server could crash with an assertion failure (or cause the client to get a “Packets out of order” error) when the expected query result was that it should terminate with a “Subquery returns more than 1 row” error. (Bug#36135)

Executing TRUNCATE statements with interleaving transactions could cause mysqld to crash. (Bug#35991)

See also Bug#22165.

Multiple threads executing repeated queries on the same Falcon table led eventually to a crash of the server. (Bug#35932, Bug#36410)

The UUID() function returned UUIDs with the wrong time; this was because the offset for the time part in UUIDs was miscalculated. (Bug#35848)

The configure script did not allow utf8_hungarian_ci to be specified as the default collation. (Bug#35808)

For CREATE TABLE, the parser did not enforce that parentheses were present in a CHECK (expr) clause; now it does. The parser did not enforce that CONSTRAINT [symbol] without a following CHECK clause was illegal; now it does. (Bug#35578, Bug#11714, Bug#38696)

Freeing of an internal parser stack during parsing of complex stored programs caused a server crash. (Bug#35577, Bug#37269, Bug#37228)

mysqlbinlog left temporary files on the disk after shutdown, leading to the pollution of the temporary directory, which eventually caused mysqlbinlog to fail. This caused problems in testing and other situations where mysqlbinlog might be invoked many times in a relatively short period of time. (Bug#35543)

The code for detecting a byte order mark (BOM) caused mysql to crash for empty input. (Bug#35480)

Index scans performed with the sort_union() access method returned wrong results, caused memory to be leaked, and caused temporary files to be deleted when the limit set by sort_buffer_size was reached. (Bug#35477, Bug#35478)

For uncorrelated subqueries without a WHERE clause, use of semi-join or materialization options could result in slow performance, or use of the LooseScan strategy could produce incorrect results. (Bug#35468)

CSV tables with CHAR columns caused BACKUP DATABASE to produce a server crash. (Bug#35117)

If a view depended on a base table that had been dropped, BACKUP DATABASE caused a server crash. (Bug#34902)

If a view was altered before backing up a database, BACKUP DATABASE caused a server crash. (Bug#34867)

Table checksum calculation could cause a server crash for FEDERATED tables with BLOB columns containing NULL values. (Bug#34779)

BACKUP DATABASE caused a server crash if it attempted to back up a view that depended on another view. (Bug#34758, Bug#35347)

A significant slowdown occurred when many SELECT statements that return many rows from InnoDB tables were running concurrently. (Bug#34409)

mysql_install_db failed if the server was running with an SQL mode of TRADITIONAL. This program now resets the SQL mode internally to avoid this problem. (Bug#34159)

Changes to build files were made to enable the MySQL distribution to compile on Microsoft Visual C++ Express 2008. (Bug#33907)

Fast ALTER TABLE operations were not fast for columns that used multibyte character sets. (Bug#33873)

ORDER BY failed to take into account accents and lettercases in multi-level collations (latin2_czech_cs and cp1250_czech_cs). (Bug#33791, Bug#30462)

The internal functions my_getsystime(), my_micro_time(), and my_micro_time_and_time() did not work correctly on Windows. One symptom was that uniqueness of UUID() values could be compromised. (Bug#33748)

The SHOW FUNCTION CODE and SHOW PROCEDURE CODE statements are not present in non-debug builds, but attempting to use them resulted in a “syntax error” message. Now the error message indicates that the statements are disabled and that you must use a debug build. (Bug#33637)

If a large number of databases were named in the BACKUP DATABASE statement, the server crashed. (Bug#33568)

Cached queries that used 256 or more tables were not properly cached, so that later query invalidation due to a TRUNCATE TABLE for one of the tables caused the server to hang. (Bug#33362)

BACKUP DATABASE did not properly set the flags in the first two bytes of the backup image. (Bug#33120)

Unindexed ORDER BY did not work on short utf32 columns, or on utf16 columns with a short max_sort_length value. (Bug#33073)

BACKUP DATABASE followed by RESTORE could mangle object names if a non-standard charset was used. (Bug#33023)

After an upgrade to MySQL 6.0.4 or higher, columns that used the old 3-byte Unicode utf8 character set are treated as having the utf8mb3 character set. mysql_upgrade did not convert all system tables in the mysql database to use the new 4-byte Unicode utf8 character set rather than utf8mb3. This caused problems such as that the event scheduler would not start. mysql_upgrade now performs the utf8mb3 to utf8 conversion for system tables. (Bug#33002, Bug#33053)

It was possible to insert invalid Unicode characters (with code point values greater than U+10FFFF) into utf8 and utf32 columns. (Bug#32914)

UNION constructs cannot contain SELECT ... INTO except in the final SELECT. However, if a UNION was used in a subquery and an INTO clause appeared in the top-level query, the parser interpreted it as having appeared in the UNION and raised an error. (Bug#32858)

Inserting CURRENT_TIME, CURRENT_DATE, or CURRENT_TIMESTAMP into a VARCHAR column didn't work for non-ASCII character sets such as ucs2, utf16, or utf32. (Bug#32390)

mysql_upgrade attempted to use the /proc filesystem even on systems that do not have it. (Bug#31605)

mysql_install_db failed if run with the default table type set to NDB. (Bug#31315)

Making INFORMATION_SCHEMA the default database caused the DROP TABLESPACE statement to be disabled. (Bug#31302)

Several MySQL programs could fail if the HOME environment variable had an empty value. (Bug#30394)

The Serbian translation for the ER_INCORRECT_GLOBAL_LOCAL_VAR error was corrected. (Bug#29738)

The BUILD/check-cpu build script failed if gcc had a different name (such as gcc.real on Debian). (Bug#27526)

ALTER TABLE could not be used to add columns to a table if the table had an index on a utf8 column with a TEXT data type. (Bug#26180)

The XPath boolean() function did not cast string and nodeset values correctly in some cases. It now returns TRUE for any non-empty string or nodeset and 0 for a NULL string, as specified in the XPath standard.. (Bug#26051)

Using ALTER TABLE with interleaving transactions could cause mysqld to crash. (Bug#22165)

The FLUSH PRIVILEGES statement did not produce an error when it failed. (Bug#21226)

After executing a prepared statement that accesses a stored function, the next execution would fail to find the function if the stored function cache was flushed in the meantime. (Bug#12093, Bug#21294)

perror did not work for errors described in the sql/share/errmsg.txt file. (Bug#10143)