Release Notes for MariaDB MaxScale 6.4.4


MariaDB MaxScale is an advanced database proxy and query router.

MariaDB MaxScale 6.4.4 was released on 2022-11-29. This release is of General Availability (GA) maturity.

Issues Fixed

Can Result in Crashes, Hangs, Stalls

  • When Schema Router (schemarouter) is used, authentication failures during shard mapping are not handled correctly. (MXS-4393)

    • In previous releases, schemarouter does not process the error, which causes the shard mapping to hang if the failing server was the last one to return a response.

    • Starting with this release, schemarouter ignores a server when it responds with an error.

  • When Schema Router (schemarouter) is used, errors can cause MaxScale to crash due to a race condition in the router's error handler. (MXS-4389)

  • When the LOAD DATA LOCAL INFILE statement is executed and autocommit is changed, the session can hang until timeout occurs. (MXS-4388)

Can Result in Unexpected Behavior

  • When an UPDATE statement references a user-defined variable, MaxScale's query classifier classifies the statement as a read statement, which can cause the statement to be routed to a replica server and can break replication (MXS-4413)

  • When the Kafka CDC Router (kafkacdc) is used, disk utilization is high. (MXS-4404)

    • In previous releases, kafkacdc truncates the current_gtid.txt file every time the router processes a GTID event.

    • Starting with this release, kafkacdc updates the current_gtid.txt file more efficiently by keeping the file handle open and writing the GTID to the file as a null-terminated string, which allows truncation to be avoided.

  • When the fields[] and filter query parameters are both used with the REST API, all results could be improperly removed by the filter. (MXS-4397)

  • MaxGUI does not use memory efficiently, which can cause the web browser to crash due to an out-of-memory (OOM) condition. (MXS-4372)

  • When using the MaxScale REST API, the /maxscale/logs/data endpoint does not filter syslog contents correctly. (MXS-4353)

  • In binary packages, librdkafka is built without SASL support enabled, which impacts the Kafka CDC Router (kafkacdc) and the Kafka Importer Router (kafkaimporter). (MXS-4348)

  • When smartrouter cancels a query, it can cancel the wrong query. (MXS-4317)

  • When MaxScale is configured to read database grants from a file using the user_accounts_file parameter and the user_accounts_file_usage parameter is set to file_only_always, MaxScale is not aware of which databases are available. (MXS-3043)

    • In previous releases, the following error is raised with the ER_BAD_DB_ERROR error code:

      Unknown database 'DATABASE_NAME'
    • Starting with this release, when MaxScale reads a database privilege from the user accounts file, it adds the database to its list of known databases.


In alignment to the MariaDB Corporation Engineering Policy, MariaDB MaxScale 6.4.4 is provided for:

  • CentOS 7 (x86_64)

  • Debian 9 (x86_64, ARM64)

  • Debian 10 (x86_64, ARM64)

  • Debian 11 (x86_64, ARM64)

  • Red Hat Enterprise Linux 7 (x86_64)

  • Red Hat Enterprise Linux 8 (x86_64, ARM64)

  • Red Hat Enterprise Linux 9 (x86_64, ARM64)

  • Rocky Linux 8 (x86_64, ARM64)

  • Rocky Linux 9 (x86_64, ARM64)

  • SUSE Linux Enterprise Server 15 (x86_64, ARM64)

  • Ubuntu 18.04 (x86_64, ARM64)

  • Ubuntu 20.04 (x86_64, ARM64)

  • Ubuntu 22.04 (x86_64, ARM64)