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Percona Server for MySQL 5.7.39-42 (2022-08-15)

Percona Server for MySQL 5.7.39-42 includes all the features and bug fixes available in MySQL 5.7.39 Community Edition in addition to enterprise-grade features developed by Percona.

Percona Server for MySQL is a free, fully compatible, enhanced, and open source drop-in replacement for any MySQL database. It provides superior performance, scalability, and instrumentation.

Percona Server for MySQL is trusted by thousands of enterprises to provide better performance and concurrency for their most demanding workloads. It delivers more value to MySQL server users with optimized performance, greater performance scalability and availability, enhanced backups, and increased visibility. Commercial support contracts are available.

Release Highlights

Improvements and bug fixes provided by Oracle for MySQL 5.7.39 and included in Percona Server for MySQL are the following:

  • To provide process information, the SHOW PROCESSLIST statement collects thread data from all active threads. Since the implementation iterates across active threads from within the thread manager while holding a global mutex, it has a negative impact on performance, particularly on busy systems.

Now, an alternative SHOW PROCESSLIST implementation is available based on the new Performance Schema processlist table. This implementation queries active thread data from the Performance Schema rather than the thread manager and does not require a mutex:

  • To enable the alternative implementation, enable the performance_schema_show_processlist system variable.

    Note

    For new installations of MySQL 5.7.39, or higher, the processlist table is automatically created in the Performance Schema. It is not created automatically by an upgrade. If you are upgrading from an earlier version of MySQL 5.7, and want to use the Performance Schema implementation of processlist, create the table manually.

Find more information in the Creating the processlist table.

  • The alternative implementation of SHOW PROCESSLIST also applies to the mysqladmin processlist command.

  • The alternative implementation does not apply to the INFORMATION_SCHEMA PROCESSLIST table or the COM_PROCESS_INFO command of the MySQL client/server protocol.

  • To ensure that the default and alternative implementations give the same information, check the configuration requirements in The processlist Table.

  • MySQL removes a 4GB tablespace file size limit on Windows 32-bit systems. The limit was set because of an incorrect calculation performed while extending the tablespace.

  • When, during a session, an incorrect value for the binlog_checksum system variable is set, a COM_BINLOG_DUMP command ran in the same session to request a binary log stream from a source fails. Now, the server validates the specified checksum value before starting the checksum algorithm setup process.

Find the full list of bug fixes and changes in the MySQL 5.7.39 Release Notes.

Deprecation and removal

  • The myisam_repair_threads system variable has been removed.

  • myisamchk --parallel-recover option has been removed.

Improvements

The SHOW PROCESSLIST statement now displays an extra field TIME_MS. The TIME_MS field provides the information about the time in milliseconds that the thread has been in its current state.

Bugs Fixed

  • PS-8205: DICT_TF2_FLAG_SET was used instead of DICT_TF2_FLAG_IS_SET.

  • PS-8174: MySQL crashed at shutdown with buf0flu.cc:3567:UT_LIST_GET_LEN(buf_pool->flush_list) == 0 assertion.

Last update: 2022-09-27