Changes in MySQL 5.7.40
Functionality Added or Changed
Important Change: The linked OpenSSL library for MySQL Server has been updated to version 1.1.1q. Issues fixed in OpenSSL version 1.1.1q are described at https://www.openssl.org/news/cl111.txt and https://www.openssl.org/news/vulnerabilities.html.
The linked curl library for MySQL Server (Enterprise Edition) has been updated to version 7.84.0.
MySQL Server’s AES_ENCRYPT() and AES_DECRYPT() functions now support the use of a key derivation function (KDF) to create a cryptographically strong secret key from information such as a password or a passphrase that you pass to the function. The derived key is used to encrypt and decrypt the data, and it remains in the MySQL Server instance and is not accessible to users. Using a KDF is highly recommended, as it provides better security than specifying your own premade key or deriving it by a simpler method when you use the function. The functions support HKDF (available from OpenSSL 1.1.0), for which you can specify an optional salt and context-specific information to include in the keying material, and PBKDF2 (available from OpenSSL 1.0.2), for which you can specify an optional salt and set the number of iterations used to produce the key.
Bugs Fixed
InnoDB: In debug builds, a descending b-tree scan raised a debug assertion failure.
InnoDB: An index latch order violation in dict_table_x_lock_indexes() caused an assertion failure.
InnoDB: A TRUNCATE TABLE operation failed to free an acquired mutex in specific cases.
The server did not always process nested views as expected.
mysqlpump might not be given the correct permissions to use derived tables (tables that are generated by a query FROM clause), causing the dump process to stop if these were present. Derived tables are now handled separately and privileges are set for them.
When using --log-timestamps=SYSTEM, ISO 8601 timestamps in log messages did not take account of daylight saving time.
The GRANT OPTION privilege was treated as related to database operations.
Changes in MySQL 5.7.39
Compilation Notes
Added macOS/ARM support.
On Windows, improved the generated INFO_BIN and INFO_SRC files.
Keyring Notes
The keyring_aws plugin has been updated to use the latest AWS Encryption SDK for C (version 1.9.186).
The keyring_aws_region variable supports the additional AWS regions supported by the new SDK. Refer to the variable description for a list of supported AWS regions.
Performance Schema Notes
The SHOW PROCESSLIST statement provides process information by collecting thread data from all active threads. However, because the implementation iterates across active threads from within the thread manager while holding a global mutex, it has negative performance consequences, particularly on busy systems.
An alternative SHOW PROCESSLIST implementation is now 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
The processlist table is automatically created in the Performance Schema for new installations of MySQL 5.7.39, or higher, and upgrades to MySQL 5.7.39, or higher.
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 yield the same information, certain configuration requirements must be met; see The processlist Table.
Functionality Added or Changed
Important Change: The linked curl library for MySQL Server (Enterprise Edition) has been updated to version 7.83.1.
Important Change: The linked OpenSSL library for MySQL Server has been updated to version 1.1.1o. Issues fixed in OpenSSL version 1.1.1o are described at https://www.openssl.org/news/cl111.txt and https://www.openssl.org/news/vulnerabilities.html.
The myisam_repair_threads system variable and myisamchk --parallel-recover option were removed.
Bugs Fixed
InnoDB: A 4GB tablespace file size limit on Windows 32-bit systems has been removed. The limit was due to an incorrect calculation performed while extending the tablespace.
Replication: The write sets extracted by MySQL Replication from transactions when the transaction_write_set_extraction system variable is enabled (which is the default) are extracted from primary keys, unique keys, and foreign keys. They are used to detect dependencies and conflicts between transactions. Previously, write sets involving multi-column foreign keys were incorrectly identifying each column as a separate foreign key. The issue has now been fixed and foreign key write sets include all referenced key columns.
Replication: When the --replicate-same-server-id option was used to make the replica not skip events that have its own server ID, if the log file was rotated, replication stopped with an error. The log rotation event now checks and applies the current value of the option.
Under certain circumstances TRUNCATE performance_schema.accounts caused duplicated counts in global_status.
This occurred only if the following was true:
If show_compatibility_56 is set to 0, aggregating status variables by accounts, users and hosts.
If some hosts were not instrumented. For example, if performance_schema_hosts_size was set to a low value.
Our thanks to Yuxiang Jiang and the Tencent team for the contribution.
Upgraded the bundled zlib library to zlib 1.2.12. Also made zlib 1.2.12 the minimum zlib version supported, and removed WITH_ZLIB from the WITH_SYSTEM_LIBS CMake option.
If an incorrect value was set for the binlog_checksum system variable during a session, a COM_BINLOG_DUMP command made in the same session to request a binary log stream from a source failed. The server now validates the specified checksum value before starting the checksum algorithm setup process.
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