Changes in MySQL 8.4.1 (2024-07-01, LTS Release)

• Audit Log Notes

• Authentication Notes

• C API Notes

• Compilation Notes

• Component Notes

• Configuration Notes

• Data Dictionary Notes

• X Plugin Notes

• Bugs Fixed

Audit Log Notes

• MySQL now calls plugin->deinit() with a valid plugin struct as an argument regardless of the plugin's type.

  Our thanks to Martin Alderete for the contribution.

Authentication Notes

• Improved log messages to provide clear reasons for access denied errors when using the authentication_ldap_sasl plugin without proxying. (Bug #35317691)

C API Notes

• C API applications stalled while receiving results for server side prepared statements.

Compilation Notes

• Upgraded the bundled googletest and googlemock sources to version 1.14.0. (Bug #36562482)

• Added a missing dependency on GenError. (Bug #36551721)

• It is now possible on Linux systems to build MySQL using a bundled tcmalloc library that is provided with the source by specifying -DWITH_TCMALLOC=BUNDLED. This is supported on Linux only. (Bug #36313839)

• Removed warnings raised in sql/statement/ed_connection.cc when building on Ubuntu 23.04. (Bug #114436, Bug #36428465)

• Linux aarch64 platform binaries are now built using patchelf --page-size=65536 for compatibility with systems using either 4k or 64k for the page size. (Bug #114233, Bug #36393794)

Component Notes

• The values for component options set using the --loose prefix were not read when the component was installed. (Bug #28341329)

Configuration Notes

• Microsoft Windows: On Windows, MySQL Configurator was updated to support in-place upgrades as per Upgrade Paths. (Bug #36685422)

• Microsoft Windows: For MSI installations on Windows, MySQL Configurator now automatically upgrades MySQL 8.4 LTS installations without user intervention. (WL #16274)

Data Dictionary Notes

• Attempting to upgrade a MyISAM table containing a mix of regular columns and generated columns from MySQL 5.7 to 8.0 or later led to table corruption. (Bug #105301, Bug #33503328)

X Plugin Notes

• The system variable caching_sha2_password_digest_rounds could not be set to a non-default value using X Protocol. (Bug #36402455)

• An outdated link to the MySQL documentation in the mysql_function_names unit test source file has been updated.

  Our thanks to Minha Jeong for the contribution. (Bug #113500, Bug #36137217)

Bugs Fixed

• InnoDB: MySQL unexpectedly halted on an UPDATE after an ALTER TABLE operation. (Bug #36571091)

  References: This issue is a regression of: Bug #35183686.

• InnoDB: The log index size calculation now accounts for column order changes. (Bug #36526369)

  References: This issue is a regression of: Bug #35183686.

• InnoDB: File system operations performed by InnoDB now consistently fsync the parent directory when performing directory altering tasks. (Bug #36174938)

• InnoDB: In debug builds, setting the innodb_interpreter_output debug variable would cause the server to unexpectedly halt. This is now a read-only variable. (Bug #36041032)

• InnoDB: Improved os_innodb_umask handling, and made it read-only. (Bug #35932118)

  References: This issue is a regression of: Bug #29472125.

• InnoDB: For tables created with an index on a column that was too wide for the redundant row format (allowed before MySQL 5.7.35), an in-place upgrade silently imported the table but it was not accessible, which interfered with making backups. Now all operations that involve using the invalid index are rejected with ER_INDEX_CORRUPT until the index is dropped. An ER_IB_INDEX_PART_TOO_LONG error is also reported in the error log. (Bug #35869747)

  References: See also: Bug #34826861.

• InnoDB: An InnoDB assertion error referencing an invalid column index was triggered when the column index was valid. (Bug #34800754)

• InnoDB: With an empty XA transaction, shutting the server down after an XA START would cause the server to halt unexpectedly. (Bug #32416819)

• InnoDB: Shutting down the replication applier or binlog applier while processing an empty XA transaction caused the system to unexpectedly halt. (Bug #32416819)

• InnoDB: Removed unnecessary heap usage in the Validate_files::check() function.

  Our thanks to Huaxiong Song for the contribution. (Bug #115041, Bug #36626203)

• InnoDB: If a partition table was read with innodb_parallel_read_threads=1, read performance greatly decreased from any table after 256 reads. InnoDB behaved as if it reached the maximum capacity of parallel read threads despite not using any.

  Our thanks to Ke Yu for the contribution. (Bug #114154, Bug #36347408)

• InnoDB: The result from a spatial index containing a column with a spatial reference identifier (SRID) attribute was empty. In addition, using FORCE INDEX to force a covering index scan on a spatial index led to an assertion. (Bug #112676, Bug #114200, Bug #35894664, Bug #36361834)

• InnoDB: SELECT ... GROUP BY queries were at least twice as slow with the TempTable engine than the Memory engine. (Bug #107700, Bug #34338001)

• Replication: If a source contained a stored, generated column populated by a JSON function and binlog_row_image was set to MINIMAL, any subsequent update or deletion on the underlying column failed with the following error:

          Invalid JSON text in argument 1 to function json_extract: 'The document is empty.'

  The replica attempted to re-evaluate the generated column and failed with that error because the underlying column was unavailable. As of this release, stored, generated columns are not re-evaluated when the underlying columns are unavailable. (Bug #36515172)

• Group Replication: Removed a memory leak from /xcom/gcs_xcom_networking.cc. (Bug #36532199)

• Group Replication: The following tables did not contain data on replication channels which did not have a configured hostname, such as Group Replication recovery channels:

  • REPLICATION_CONNECTION_STATUS

  • REPLICATION_CONNECTION_CONFIGURATION

  • REPLICATION_APPLIER_CONFIGURATION

  • REPLICATION_APPLIER_STATUS

  • REPLICATION_APPLIER_STATUS_BY_COORDINATOR

  • REPLICATION_APPLIER_STATUS_BY_WORKER

  As of this release, these tables contain data for partially configured Group Replication channels. (Bug #36018242)

• JSON: Added missing checks for error handling to NULLIF(), COALESCE(), and the shift (>>) operator. (Bug #113668, Bug #35513196, Bug #36198403)

  References: See also: Bug #31358416.

• MySQL NDB ClusterJ: Running the ClusterJ test suite resulted in an error message saying a number of threads did not exist. That was due to some wrong handling of threads and connections, which was corrected by this patch. (Bug #36086735)

• On macOS, reinstated the MySQL preference pane's ability to load a custom my.cnf configuration file. This includes loading it before initializing a new data directory. (Bug #36630493)

• On Fedora 40, there were conflicts when installing MySQL 8.4.0 community server on a system with native mysql-server packages present. (Bug #36575524)

• Averages of certain numbers were not always computed correctly. (Bug #36563773)

• The following files in strings contained incorrect license information:

  • mb_wc.h

  • ctype-uca.cc

  • ctype-ucs2.cc

  • ctype-utf8.cc

  • dtoa.cc

  • strxmov.cc

  • strxnmov.cc

  (Bug #36506181)

• In certain unusual cases, the UpdateXML() function did not process all of its arguments correctly. (Bug #36479091)

• Explaining a query which used FORCE INDEX on a spatial index containing a column with SRID attributes led to an unplanned exit. (Bug #36418426)

• Added the ER_LOG_PARTITION_PREFIX_KEY_NOT_SUPPORTED error definition, which references functionality added in MySQL 8.4.0. (Bug #36350938)

• Updated BuildRequire rules to align with versions now required for CMake and Bison. (Bug #36343254)

• Some prepared statements were not reprepared correctly. (Bug #36267792)

  References: This issue is a regression of: Bug #34929930.

• When incrementing the reference count for an expression, underlying expressions within this expression are not looked at. While removing an expression, after decrementing the reference count, even the underlying expressions were examined, which led to unintentional deletion of the underlying expressions. This issue manifested in Item_ref::real_item() as well as in an assert in sql/item.h. We fix this by not looking at the underlying expression unless the current expression contains the only remaining reference. (Bug #36204344, Bug #36356279)

• Under certain conditions, EXPLAIN FORMAT=JSON FOR CONNECTION sometimes led to an unplanned exit. (Bug #36189820)

• Under certain conditions, a race condition could result in the amount of RAM used by TABLE_HANDLES increasing to a maximum of 9GB. (Bug #36170903)

• Some CREATE USER statements were not handled correctly. (Bug #36022885)

• For a SELECT with ORDER BY and LIMIT, the optimizer first chose a full table scan with a very expensive cost, then performed another check and used the perform_order_index type of path, but this was not reflected by the cost in the optimizer plan. (Bug #35930969)

• Executing mysqldump on a replica would insert the FLUSH TABLES operation, an operation that writes to the binary log. Now FLUSH LOCAL TABLES is inserted instead to prevent GTID related issues during replication due to these binary log changes.

  The workaround was to set the --source-data option to 1 or 2. (Bug #35665076)

  References: This issue is a regression of: Bug #33630199.

• All internal ACL bitmask variables are now explicitly 32 bits (uint32_t). (Bug #35507223)

• It was not possible to add a functional index on FIND_IN_SET(). (Bug #35352161)

• Running two concurrent OPTIMIZE TABLE statements on the same table with fulltext indexes and innodb_optimize_fulltext_only enabled sometimes caused the server to exit. (Bug #34929814)

• In some circumstances, such when DDL operations were performed on a very large number of tables, the error log was flooded with warnings from background histogram updates; the offending warning was concerning a failure to acquire metadata locks on a table.

  To remedy this problem we now throttle messages written to the error log from background histogram update operations, the rate being capped at one message per minute, which should suffice for the user to identify potential problems with background histogram updates. In addition, we downgrade all error events that occur during background histogram updates from errors to warnings. (Bug #114845, Bug #36574298)

• On macOS, the DMG now installs the keyring component instead of installing keyring plugin functionality that was removed in MySQL Server 8.4.0.

  The 8.4.0 workaround was to disable the "Keyring Data File" option in the preference pane or to manually remove the two keyring lines from the launchd plist. (Bug #114836, Bug #36577944)

• It was possible for a deterministic stored function to return an incorrect result when the function used JOIN ON inside the return statement. If the query needed to be reprepared due to a table metadata caused by, for example, FLUSH TABLES between two executions, the ON clause was sometimes lost. (Bug #114235, Bug #36379879)

• Added the missing mysql-community-libs-compat package for the EL8 and EL9 platforms. (Bug #112949, Bug #35975348)

• The PROCESSLIST_INFO column of THREADS was not updated when executing a prepared statement. (Bug #104121, Bug #33057164)