Percona Distribution for MySQL 8.4.5 using Percona Server for MySQL (2025-05-29)

Percona Distribution for MySQL is more than just a version of MySQL; it is a comprehensive solution that combines Percona Server for MySQL with additional tools to create a cohesive environment. This distribution is reliable, scalable, and secure, ensuring that all components have been tested to work seamlessly together. You can choose from two download options: one that uses Percona Server for MySQL and another that utilizes Percona XtraDB Cluster. Refer to Install Percona Distribution for MySQL.

This release is based on Percona Server for MySQL 8.4.5-5 that includes all the features and bug fixes available in the MySQL 8.4.5 Community Edition and enterprise-grade features developed by Percona.

Release highlights

Percona Server for MySQL 8.4.5-5

• Updates the C++ level of the KMPI library to enhance error handling capabilities.

• Improves optimizer behavior by restoring correct handling of const tables in test_quick_select(). A MySQL Upstream refactor (commit 9a13c1c) removed the QEP_TAB dependency, causing get_quick_record_count() to no longer pass const table information. This could lead to suboptimal range scan boundaries. The applied patch resolves the issue by explicitly passing const_tables to test_quick_select(), ensuring consistent behavior with the pre-refactor logic.

The latest MyRocks storage engine incorporates code based on RocksDB version 9.3.1. Percona has applied minor modifications to the original RocksDB codebase. Check the list of modifications at https://github.com/percona/rocksdb/.

This release adds the following changes to the list of MyRocks variables.

Adds new MyRocks variables

• --rocksdb_bulk_load_compression_parallel_threads
• --rocksdb_bulk_load_enable_unique_key_check
• --rocksdb_debug_skip_bloom_filter_check_on_iterator_bounds
• --rocksdb_enable_udt_in_mem
• --rocksdb_invalid_create_option_action
• --rocksdb_io_error_action
• --rocksdb_table_stats_skip_system_cf
• --rocksdb_use_io_uring
• --rocksdb_enable_instant_ddl
• --rocksdb_enable_instant_ddl_for_append_column
• --rocksdb_enable_instant_ddl_for_column_default_changes
• --rocksdb_enable_instant_ddl_for_drop_index_changes
• --rocksdb_enable_instant_ddl_for_table_comment_changes
• --rocksdb-bulk-load-compression-parallel-threads
• --rocksdb-bulk-load-enable-unique-key-check
• --rocksdb-debug-skip-bloom-filter-check-on-iterator-bounds

Changes default values of MyRocks variables

• --rocksdb_disable_instant_ddl - the default value is changed from ON to OFF.

• --rocksdb_file_checksums - the data type is changed from Boolean to ENUM. Also, the default value is changed from OFF to CHECKSUMS_OFF.

• --rocksdb_compaction_readahead_size - the default value is changed from 0 (zero) to 2097152.

Deprecates MyRocks variable

• --rocksdb_disable_instant_ddl - this variable is being deprecated and is expected to be removed in a future release.

Removes MyRocks variables

• --rocksdb-access-hint-on-compaction-start
• --rocksdb_large_prefix
• --rocksdb_strict_collation_check
• --rocksdb_strict_collation_exceptions

MySQL 8.4.5

Improvements and bug fixes introduced by Oracle for MySQL 8.4.5 and included in Percona Server for MySQL are the following:

• Fixed an issue where CHECK TABLE sometimes incorrectly reported that spatial indexes were corrupted. (Bug #37286473)

• Fixed an issue in InnoDB redo log recovery to improve data safety after a crash. (Bug #37061960)

• Fixed an issue where reading index_id values could lead to incorrect behavior with indexes. (Bug #36993445, Bug #37709706)

• Fixed a bug related to the lower_case_table_names setting that caused inconsistent behavior with table names on different systems. (Bug #32288105)

• Fixed a bug where mysqldump did not properly escape certain special characters in its output. (Bug #37540722, Bug #37709163)

• The fprintf_string() function in mysqldump did not use the correct quote character for escaping strings. (Bug #37607195)

Find the complete list of bug fixes and changes in the MySQL 8.4.5 release notes.

Known issues

• ProxySQL contains counters that have not been updated to use the new terminology. Unexpected results may occur. In an 8.4.x environment, the binlog reader errors out during initialization due to the use of old terminology, such as the SHOW MASTER STATUS command.

Supplied components

Review each component’s release notes for What’s new, improvements, or bug fixes. The following is a list of the components supplied with the Percona Server for MySQL-based variation of the Percona Distribution for MySQL.

Component	Version	Description
Orchestrator	3.2.6-17	The replication topology manager for Percona Server for MySQL
ProxySQL	2.7.3	A high performance, high-availability, protocol-aware proxy for MySQL
Percona Toolkit	3.7.0-2	The set of scripts to simplify and optimize database operation.
Percona XtraBackup	8.4.0-3	An open-source hot backup utility for MySQL-based servers
MySQL Shell	8.4.5	An advanced client and code editor for MySQL Server
MySQL Router	8.4.5	Lightweight middleware that provides transparent routing between your application and back-end MySQL servers