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MySQL 5.6 Release Notes  /  Changes in MySQL 5.6.30 (2016-04-11, General Availability)

Changes in MySQL 5.6.30 (2016-04-11, General Availability)

Security Notes

  • The linked OpenSSL library for the MySQL Commercial Server has been updated to version 1.0.1s. For a description of issues fixed in this version, see

    This change does not affect the Oracle-produced MySQL Community build of MySQL Server, which uses the yaSSL library instead. (Bug #22685885, Bug #22923458)

  • MySQL client programs now support an --ssl-mode option that enables you to specify the security state of the connection to the server. If the option is not specified, the default value is DISABLED (establish an unencrypted connection). --ssl-mode=REQUIRED can be specified to require an encrypted connection, or fail if an encrypted connection cannot be obtained.

    These clients support --ssl-mode: mysql, mysqladmin, mysqlcheck, mysqldump, mysqlimport, mysqlshow, mysqlpump, mysqlslap, mysqltest, mysql_upgrade.

    For more information, see Command Options for Encrypted Connections.


    In MySQL 5.7 and higher, the C client library provides native support for requiring encrypted connections: call the mysql_options() C API function, passing the MYSQL_OPT_SSL_MODE option with a value of SSL_MODE_REQUIRED. In MySQL 8.0, the client library provides no such support because doing so would break binary compatibility with previous library versions within the series. Clients that require encrypted connections must implement the logic themselves.

    To require encrypted connections in MySQL 8.0, the standard MySQL client programs use this technique: If --ssl-mode=REQUIRED was specified, the client program turns on SSL, connects to the server, and checks whether the resulting connection is encrypted. If not, the client exits with an error. Third-party applications that must be able to require encrypted connections can use the same technique. For details, see mysql_ssl_set().

Bugs Fixed

  • InnoDB; Partitioning: When OPTIMIZE TABLE rebuilt a partitioned InnoDB table, it placed the resulting partition tablespace files (*.ibd files) in the default data directory instead of the directory specified using the DATA DIRECTORY option. (Bug #75112, Bug #20160327)

  • InnoDB: Running REPLACE operations on multiple connections resulted in a hang. (Bug #22530768, Bug #79185)

  • InnoDB: MySQL stalled when synchronizing the InnoDB full-text index cache. (Bug #22516559, Bug #16510576, Bug #73816)

  • InnoDB: A CREATE TABLE ... DATA DIRECTORY operation failed to create a table while innodb_flush_method was set to O_DIRECT. (Bug #22180006, Bug #79200)

    References: This issue is a regression of: Bug #21113036.

  • InnoDB: The innodb_open_files setting could exceed the open files limit. (Bug #22111472)

  • Replication: Issuing STOP SLAVE caused a spurious Error reading packet from server: Lost connection to MySQL server during query message to be written to the error log. With this fix, when connection to the master is lost, the abort_slave flag is checked and the error message is printed only if the flag is not set. (Bug #22305605, Bug #79504)

    References: See also: Bug #12977988, Bug #22290309.

  • Replication: When a multithreaded slave stopped with an error, the same error message was printed three times. Now, the SQL thread's kill acceptance status is saved, and only printed once. (Bug #21198611, Bug #77237)

  • Replication: mysqlbinlog --verbose displayed BINARY and VARBINARY data as ordinary strings, causing any single quote (') or backslash (\) among the data to be printed as such, which was confusing to the users and, in the case of a backslash, caused the next character to be skipped. This fix makes mysqlbinlog print the characters' hexadecimal values (\x27 for single quote and \x5c for backslash) instead. (Bug #20836250)

  • Replication: The test case main.merge failed when the variables binlog_format was set to ROW, as the server tried to get information for table creation for a child table before it was opened. With this fix, the server skips getting information for the table in the situation. (Bug #20574550, Bug #75976)

  • Replication: If a query on a master generated an error and partial results were written to the binary log, for example due to a DROP TABLE IF EXISTS statement applying to multiple tables that would break foreign key constraints, when a slave configured with replication filters encountered the query it could be incorrectly binary logged. This caused errors such as:

    Last_SQL_Error: Query caused different errors on master and slave. Error on master: message (format)='Cannot delete or update a parent row: a foreign key constraint fails' error code=1217 ; Error on slave: actual message='no error', error code=0. Default database: 'db1'. Query: 'DROP TABLE IF EXISTS `table1` /* generated by server */'

    There were two fixes required for this bug.

    • If a DROP TABLE statement used to drop a single table fails, to avoid partial results causing this bug the query is not written to the binary log. If a DROP TABLE statement used to drop a list of tables fails, any partial results it generates are written to the binary log with an error.

    • When a query that generates an error as expected was received by a slave but it was skipped due to replication filters, the slave was incorrectly checking the error. The fix for Bug #76493 ensures that this comparison of the expected error from the master with the actual error from the slave does not happen.

    (Bug #77684, Bug #21435502)

    References: See also: Bug #20797764, Bug #76493.

  • Integer overflow could occur during client handshake processing, leading to a server exit. (Bug #22722946)

  • The System-V initialization script for RHEL6 or older failed to enable the mysqld service by default. (Bug #22600974)

  • When ExtractValue() found no match for the supplied expression, it returned NULL instead of an empty string as expected.

    This issue affected MySQL 5.6.28 and 5.6.29 only. (Bug #22552615)

  • Improper host name checking in X509 certificates could permit man-in-the-middle attacks. (Bug #22295186, Bug #22738607)

  • A boolean mode full-text search caused a segmentation fault. (Bug #22176795)

  • Concurrent selecting and flushing of a FEDERATED table while killing connections accessing it could result in a server exit. (Bug #21918190)

  • Executing GRANT PROXY statements after altering the definition of the mysql.user system table could result in a server exit. (Bug #21699037)

  • Certain error messages included part of the SQL statement that produced them, possibly exposing data. (Bug #21682356)

  • Although it is possible to create nontemporary tables using the prefix #sql, Performance Schema assumed that tables named using this prefix were temporary and could be ignored. Performance Schema now uses table attributes other than the name to identify temporary tables. (Bug #21105475, Bug #22532368, Bug #79934)

  • Account filtering performed by the audit_log plugin incorrectly used the account named by the USER() function rather than the CURRENT_USER() function (the latter being the account used for authentication). (Bug #19509471, Bug #22454245, Bug #77553)

  • Character set conversion operations on NULL parameters to prepared statements could cause a server exit. (Bug #18823979)

  • Loose Index Scan was not chosen for queries that had an equality condition. (Bug #18109609)

  • A MySQL 5.6 server exited during startup if used with a 5.7 data directory due to the change in 5.7 of the mysql.plugin table from MyISAM to InnoDB. A safe shutdown now occurs in this circumstance. (Bug #79290, Bug #22216779)

  • For INSERT and UPDATE operations that caused FOREIGN KEY constraint violations, errors were reported rather than warnings when the IGNORE keyword was used. (Bug #78853, Bug #22037930)

    References: See also: Bug #23135731.

  • For some queries, an Index Merge access plan was chosen over a range scan when the cost for the range scan was the same or less. (Bug #77209, Bug #21178196)

  • Certain queries could raise an assertion when a internal string operation produced a NULL pointer rather than an empty string. (Bug #74500, Bug #19875294, Bug #13358486, Bug #79988, Bug #22551116)

  • EXPLAIN for SELECT ... FOR UPDATE statements acquired locks. (Bug #72858, Bug #18899860)

  • Processlist state information was not updated correctly for LOAD DATA and could show a state different from executing. (Bug #69375, Bug #16912362)