MySQL 9.5: Key Features and Performance Enhancements

MySQL 9.5 is here! 🚀

Explore the latest features and enhancements in this release.

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Account and Permission Management​

• ​Mandatory Role Activation: The activate_mandatory_rolesoption now controls the activation logic for mandatory roles. When activate_all_roles_on_loginis disabled, accounts automatically activate mandatory and default roles.
• ​Connection Control: The new component_connection_control.exempt_unknown_userssystem variable exempts failed connections without user credentials from delay penalties. The status variable Component_connection_control_exempted_unknown_userstracks exempted connections.

​Performance Optimizations​

• ​Binary Logging: binlog_transaction_dependency_history_sizedefaults to ​1,000,000​ (max: 10,000,000), improving dependency tracking for large transactions.
• ​InnoDB Enhancements:
  • innodb_log_writer_threadsdynamically adjusts based on binary log status and CPU count.
  • innodb_change_bufferingnow defaults to ALLfor better secondary index updates.
• ​Thread Pool Auto-Tuning: The thread pool plugin automatically configures thread_pool_sizeand four other variables based on vCPU count.

​Security Upgrades​

• ​Authentication:
  • caching_sha2_password_digest_roundsdefaults to ​10,000​ for stronger password hashing.
  • SCRAM-SHA-1 is deprecated; SCRAM-SHA-256 is now the default.
• ​Replication Security:
  • All replication connections are encrypted by default (SOURCE_SSL=1, group_replication_ssl_mode=REQUIRED).
• ​Key Management:
  • component_keyring_kmipsupports Oracle Key Vault 21.10+ SECRETkey types.
  • keyring_okvis deprecated and replaced by keyring_kmip.

​JavaScript and JSON Improvements​

• ​JavaScript Stored Procedures:
  • Larger result sets are now supported.
  • MLE components comply with ECMAScript 2025.
  • mle.memory_maxauto-configures based on physical memory (5%, 0.4GB–32GB range).
• ​JSON Optimizations:
  • Fixed parsing errors for high-precision floats and TIMEvalue serialization.
  • JSON Duality Views now prevent deletion of single nested sub-objects.

​New Diagnostic Tool​

• ​MySQL Diagnostic Monitor (mysqldm)​: A new client tool collects server diagnostics in JSON format, with customizable output directories, iterations, and intervals.

​Other Key Updates​

• ​Deprecations: Removed outdated variables (e.g., group_replication_allow_local_lower_version_join) and plugins (e.g., semisync_primary/semisync_replica).
• ​Execution Plan Display: explain_formatnow defaults to TREEfor clearer query analysis.
• ​Sys Schema: The revoke_schema_privileges_from_all_accounts_except()procedure simplifies bulk privilege revocation.

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