This document describes the changes in release 23.08.3, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Crash on maxctrl list sessions

• Relative paths do not work when defined in the configuration file

• Binlog encryption broken

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.8, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• ssl_version should specify minimum version

Bug fixes

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.6, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Crash on maxctrl list sessions

• Handshake response packet size limit is too strict

• Binlog encryption broken

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

Release 25.01.5 is a GA release.

This document describes the changes in release 25.01.5, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 24.02.8, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 23.08.1, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

External CVEs resolved.

This document describes the changes in release 23.02.16, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 23.02.1, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

New Features

This document describes the changes in release 22.08.11, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 22.08.10, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 24.02.6, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Maxctrl interactive mode doesn't use --tls-verify-server-cert=false

• The logout screen is shown when accessing the MaxGUI login view.

• optimistic_trx causes a query to hang

• Processing of conditional headers is incorrect

• MaxCtrl fails to read large inputs from stdin

• admin_oidc_url is documented to not be dynamic when in fact it is

• REST-API always sends a Connection: close header

• Signal 11 crash when enabling causal reads with Galera

• Add a Service with a CLUSTER as its target breaks CONFIG SYNC

• Aborted connection on backend mariadb with persistpool maxscale

• Maxctrl config permission check error message is misleading

• Wrong password in interactive mode is only seen after the first command

• --secretsdir has no default value

• Query Editor default connection type preference is changed unexpectedly

• Using PKCS#1 private key in the REST-API results in cryptic errors

• Trailing parts of large session command are not routed correctly

• Prepared statements fail through schemarouter for Columnstore

• Masking with functions uses wrong rule settings

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 24.02.1, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

External CVEs resolved.

• Fixed by Upgrade libssh to 0.10.6

• Fixed by Upgrade libssh to 0.10.6

• Fixed by Upgrade libssh to 0.10.6

• Fixed by Upgrade libssh to 0.10.6

• Fixed by Upgrade libssh to 0.10.6

New Features

• Add disk_space_ok option to master_conditions and slave_conditions

Bug fixes

• Setting a path argument to empty reads uninitialized memory

• REST-API TLS keys are not validated at runtime

• MaxScale should prevent incompatible TLS certificates from being configured

• enforce_read_only_slaves can set master to read_only

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.08.12, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• No error message if connection to server fails during start of switchover

• SHOW CREATE TABLE doesn't detect if a temporary table is used

• Signal 11 crash

• Default users_refresh_interval causes repeated user account loading

• maxctrl create report --archive error reporting produces errors

• kafkacdc doesn't escape db name identifiers resulting in errors

• Database names with dashes are not properly escaped when disabling events

• Fix for MXS-5196 can break "maxctrl create report"

• MaxKeys usage message is obsolete

• Rebuild Replica fails when using MaxScale encrypted password for monitor user

• MariaDBMon should not solely depend on "STOP SLAVE" when doing failover/switchover

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.08.10, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Maxctrl interactive mode doesn't use --tls-verify-server-cert=false

• The logout screen is shown when accessing the MaxGUI login view.

• optimistic_trx causes a query to hang

• Processing of conditional headers is incorrect

• MaxCtrl fails to read large inputs from stdin

• admin_oidc_url is documented to not be dynamic when in fact it is

• REST-API always sends a Connection: close header

• Signal 11 crash when enabling causal reads with Galera

• Add a Service with a CLUSTER as its target breaks CONFIG SYNC

• Aborted connection on backend mariadb with persistpool maxscale

• Maxctrl config permission check error message is misleading

• Wrong password in interactive mode is only seen after the first command

• --secretsdir has no default value

• Using PKCS#1 private key in the REST-API results in cryptic errors

• Trailing parts of a large session command are not routed correctly

• kafkacdc commits offsets when it probes GTIDs from Kafka

• Logs Archive page doesn't show a useful API error

• Masking with functions uses the wrong rule settings

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to thedocument.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.08.4, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• SSL_VERSION should have a way to disallow deprecated versions

Bug fixes

• Startup option --basedir mishandled

• Parameter table isn't refreshed after update in the GUI

• GUI doesn't show and allow to edit connection_metadata after a listener is created

• maxscale 23.08.3 crash with dump_last_statements=on_close set

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.7, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Startup option --basedir mishandled

• Parameter table isn't refreshed after update in the GUI

• GUI failed to create a monitor in a monitored server detail page

• No space or separator between 2 routing targets in the services dashboard

• Broken slave promoted to master when no other servers are available

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

Release 2.5.27 is a GA release.

Released: 27 Jul 2023

This document describes the changes in release 2.5.27, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Provide a way to show details about all supported MaxScale modules via REST API and/or MaxCtrl

Bug fixes

• REST-API documentation is wrong about which server parameters can be modified

• The fact that readconnroute doesn't block writes with router_options=slave is not documented

• Listener creation error is misleading

• Cache filter hangs if statement consists of multiple packets.

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the Limitations document.

Packaging

RPM and Debian packages are provided for supported the Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

Release 2.5.26 is a GA release.

Released: 23 May 2023

This document describes the changes in release 2.5.26, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Partially executed multi-result queries are not treated as partial results

• Query classifier does not recognize BEGIN NOT ATOMIC ... END

• Readwritesplit prefers idle primary over busy replicas

• transaction_replay_max_size default is 1GiB instead of 1MiB

• Not all passwords were obfuscated in the maxctrl report

• Regular expression documentation is inaccurate and lacking

• KB pages reference mysqlauth and mysqlauth is deprecated for mariadbauth

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the Limitations document.

Packaging

RPM and Debian packages are provided for supported the Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 21.06.18, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

External CVEs resolved.

This document describes the changes in release 25.01.4, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please see .

For any problems you encounter, please consider submitting a bug report on .

New Features

This document describes the changes in release 25.01.3, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please see .

For any problems you encounter, please consider submitting a bug report on .

This document describes the changes in release 24.02.3, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 23.08.11, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please see .

For any problems you encounter, please consider submitting a bug report on .

New Features

This document describes the changes in release 23.02.11, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 22.08.14, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 22.08.7, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

New Features

This document describes the changes in release 22.08.6, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

This document describes the changes in release 22.08.5, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

• Sessions can now be restarted so that added server are taken into use.

• Sessions can now be killed using maxctrl.

• MariaDBMonitor can use mariadb-backup to clone the contents of a server.

• The diagnostic output of maxctrl show filter now shows the rules of a filter, if it has such.

• At startup, if there are filters that are not used by any service, or servers that are not referred to by any service or monitor, a warning will be logged.

• net_write_timeout now also affects backend connections.

Release 2.5.25 is a GA release.

Released: 30 Mar 2023

This document describes the changes in release 2.5.25, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

Release 2.5.18 is a GA release.

Released: 12 Jan 2022

This document describes the changes in release 2.5.18, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

Release 2.5.24 is a GA release.

Released: 4 Jan 2023

This document describes the changes in release 2.5.24, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on .

Bug fixes

Release 25.10.0 is a GA release. It was released on 2025-10-22.

This document describes the changes in release 25.10, when compared to release 25.01.

For any problems you encounter, please consider submitting a bug report on our Jira.

Changed Features

Dropped Features

The global settings query_retry and query_retry_timeout, as well as the monitor settings backend_write_timeout and backend_read_timeout have been removed. The settings are still recognized but any configured values are ignored.

Deprecated Features

The global settings event.authentication_failure.facility and event.authentication_failure.level have been deprecated and renamed to event_authentication_failure_facility and event_authentication_failure_level respectively.

The monitor setting backend_connect_timeout has been deprecated. Use backend_timeout instead.

New Features

Add auto_failback_switchover to MariaDB Monitor

Restores the old primary server to primary status once it rejoins the cluster after failover. See for more information.

Add redirect command to MariaDB Monitor

Manually alters replication topology.

Export Otel metrics from MaxScale

MaxScale can now send metrics to an OpenTelemetry Collector.

Galera Monitor bootstrap command

The Galera monitor can now bootstrap itself from an existing Galera cluster. Please see the Galera Monitor for more information.

Add list-backups command to MariaDB Monitor

Lists available backups in the backup storage.

Use new SESSION AUTHORIZATION feature from 12.0

If MaxScale is used with MariaDB 12.0 and the service user has the required grants to switch users, the backend authentication will be done with the service user credentials and the new SET SESSION AUTHORIZATION command is used to switch the user account to the one that the client is requesting. This makes the authentication between MaxScale and MariaDB very flexible and allows it to use an efficient, secure and fast authentication mechanism like ed25519 or PARSEC while still supporting all possible authentication mechanisms between the client and MaxScale.

To disable this feature, add use_service_credentials=false to the server section.

Copy new server from existing server

When creating a server using maxctrl it is now possible to copy all nonspecified settings from an existing server.

Improve backup operation progress tracking

MariaDB Monitor backup operation status can be shown in detail with the command.

Test backup operation prerequisites

MariaDB Monitor (rebuild-server, create-backup, restore-from-backup) now support key-value arguments. The commands also support the dry-run-option, which checks if MaxScale configuration and servers support the commands.

Read maxctrl section from maxscale.cnf if present

If there is a [maxctrl] section in the MaxScale configuration file, maxctrl will read settings from there if it's readable. This makes it easier to enable encryption and to define the credentials that are used to access MaxScale.

Add configuration option for assigning the initial server state

With the initial_status setting, the initial state of all servers can be set to either down, up, read or write. This allows manual assignment of server states for special cases where monitoring is either not needed or doesn't produce the expected result.

Simplified way for issuing module commands

The first value in the maxctrl call command can now also be the name of an object in MaxScale instead of the module name. This makes it much more convenient to call the module command of the correct object.

For example, maxctrl call command mariadbmon switchover My-Monitor can now be done with maxctrl call command My-Monitor switchover.

Support zstd protocol compression

MaxScale now supports the newer zstd as well as the older zlib compression at the protocol level. Unlike MariaDB and MySQL, which have a fixed compression threshold of 50 bytes, MaxScale can be customized to compress at a custom threshold with the mariadbprotocol.compression_threshold setting to reduce the CPU cost for small payloads.

To disable support for the protocol level compression, set mariadbprotocol.compression=none in the listeners.

Enable implicit creation of filters

A filter that does not have any configuration settings can be directory used in the configuration section of a service, without a configuration section of its own. See the for more information.

Filter for controlling what statements are allowed

The implicit filter can be used for preventing writes to a server.

Property support [create|drop|list] indexes

The NoSQL protocol now supports the use of indexes. See for more information.

Support MariaDB multi-authentication

MaxScale now supports the use of multiple authentication plugins for both client and backend authentication. The set of supported plugins can be configured with the authenticator setting in the listeners. For example to enable both traditional mysql_native_password and the newer PARSEC authentication, use authenticator=mariadbauth,parsecauth in the listeners.

Add database firewall

MaxScale now contains a that first learns what statements are allowed and then rejects statements that are not allowed.

Galera cluster discovery

Added and commands to Galera Monitor. bootstrap populates an empty monitor. discover-replicas finds new servers to add to the monitor and optionally removes disconnected servers.

Replication cluster discovery

Added , and commands to MariaDB Monitor. scan-topology is mainly useful in checking if all servers in the replication cluster are monitored. bootstrap populates an empty monitor. discover-replicas finds new servers to add to the monitor and optionally removes disconnected servers.

React to redirect_url from backends

MaxScale will rename the redirect_url server variable change in the response from a server to mxs_rdir_url before the packet is returned to clients. This is to prevent someone from inadvertently bypassing MaxScale by doing a SET GLOBAL redirect_url through MaxScale. Redirecting clients away from MaxScale, should be done via maxctrl alter service ... redirect_url=<URL>.

Connection redirection: add redirect_url parameter

MaxScale now has a configuration setting using which clients can be redirected away from MaxScale.

Add a way to configure preference of servers

Using the new it is possible to affect the server selection order in ReadConnRoute.

Allow customization of fields in maxctrl list commands

With the --fields flag the output of maxctrl can be customized. For instance:

Verify REQUIRE (X509|ISSUER|SUBJECT|CIPHER) on maxscale side

MaxScale now enforces the REQUIRE (X509|ISSUER|SUBJECT|CIPHER) clauses on user definitions. Please see the server documentation for more information.

Add role support to monitors and services

Monitors and service will activate the configured role when logging in. See and settings for more information.

Introduce a new core_file variable in MaxScale

By default, MaxScale no longer generates a core file when it crashes. Please see for more information.

Add setting to control servers participating in cooperative monitoring

excludes listed servers from cooperative monitoring.

Include actual line content in parse error message

When configuration file parsing fails in an early phase, the actual offending line will now be logged in the error message to make it easier to pinpoint the problem.

Clarify log messages regarding lost server locks

Support for PARSEC auth plugin from MDEV-32618

MaxScale now supports authentication.

Separate read-write/read-only and master/slave

In the output of maxctrl list server, the state of a server and reason for the state are now separated. The state of a server is shown as Read, Write, Up or Down, possibly augmented with Maintenance or Draining|Drained, while the reason for the state is shown in the next column. For instance, in a Primary/Replica cluster, the reason for the state Read may be Primary, read_only, indicating that although the server is the primary, it has read_only turned on, so it cannot be used for writing.

Reset router diagnostics statistics

Using maxctrl, it is now possible to clear both server and service statistics.

Support server side ephemeral certificates

MaxScale can connect to a MariaDB Server that is using a self-signed certificate and verify the certificate. See for more information.

Support client side ephemeral certificates

MaxScale can generate a self-signed certificate and a supporting client can verify it. See for more information.

Make it possible to dump the query classifier cache to a file

Using maxctrl it is now possible to dump the content of the query classifier cache to a file. The cache can be dumped as json, as pretty formatted json and as json lines, i.e. as json objects separated by a newline.

MaxScale should warn about inconsistencies in the configuration file

• At startup, if there are filters that are not used by any service, or servers that are not referred to by any service or monitor, a warning will be logged.

Add replication information to maxctrl list servers

The maxctrl list servers command now also has a customizable field for replication lag information. To use it, add replication-lag to the list in the --fields option.

Add global setting require_secure_transport

The global setting forces encryption to be configured everywhere.

Mechanism for throttling of write queries based on replica lag

A new feature in the readwritesplit router that synchronizes committed transactions on one or more replicas by waiting for the transaction to be replicated. It has two modes of operation: the soft mode synchronizes the transactions but proceeds normally if a synchronization timeout occurs and the hard mode which will close the client session if synchronization times out. The sync_transaction_max_lag setting can be used to adjust when the throttling takes place and sync_transaction_timeout controls the maximum amount of lag that the client applications will experience.

This feature can be used to limit the amount of replication lag that the cluster will see. It also provides a way to have fully synchronous replication with MariaDB with stronger durability guarantees than is possible with semi-synchronous replication.

Improve REST-API Access Control

The MaxScale GUI and REST-API now use role based access control to restrict the operations that users can do. The admin and basic roles both retain their old behavior of the former being allowed to do anything and the latter being only able to perform read-only operations. The new editor role has the ability to also modify objects but it lacks the ability to create, modify or delete users and roles. The new sql role is only allowed to access the query API and the Workspace in the GUI.

User-defined roles can also be added with the maxctrl create role command. The permissions that the roles have are admin for creating users, edit for creating, modifying and destroying objects, view for viewing information about objects and MaxScale itself and sql for accessing the SQL query API.

Run SQL commands on primary and replica whenever status changes

Run custom SQL on a server when it gains a primary or replica role. See and for more information.

Support for passphrase protected certificate keys

It is now possible to use passphrase protected certificate keys. Please see and for more information.

MaxGUI

Numerous additions have been added and improvements made to MaxGUI. The most notable ones are listed here:

• Highlight changed parameters

• Query Editor: Add UI for creating and altering users

• Backup operations UI

Bug fixes

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

This document describes the changes in release 24.02.2, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Add "enforce_read_only_servers" feature to MariaDB Monitor

Bug fixes

• Server version checks are overly pessimistic

• Connection busy error occurs when connecting to a listener in the Query Editor

• MariaDB Monitor can kill connections from other monitors during switchover

• Master Stickiness state is not documented

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

• The default values of some readwritesplit parameters have been updated. The new default values are:

  • master_reconnection=true

  • master_failure_mode=fail_on_write

  • strict_tmp_tables=true

  • transaction_replay_timeout=30s

• MariaDB-Monitor now requires MariaDB Server 10.4 or newer for failover/ switchover. Server 10.3 is end of life.

• Server setting private_address added. Used for detecting and setting up replication. See for more information.

• MariaDB-Monitor allows customization of some mariadb-backup settings. See and for more information.

• MariaDB-Monitor setting servers_no_promotion now affects primary server selection during MaxScale startup or due to replication topology changes.

• Pam authentication now always checks account status. Previously, this check was not performed if MaxScale was configured for username mapping (authenticator_options=pam_backend_mapping=mariadb). This means that if username mapping is configured in the OS pam service config, the final username must be a valid user. This is similar to MariaDB Server behavior.

• Support for the legacy SysV and Upstart system managers has been removed. In practice this change will not affect anything as all supported operating systems use SystemD as the system manager and MaxScale has long preferred it over the legacy systems.

• The output of maxctrl show service now includes the statistics for the services.

• The max_sescmd_history_length and avg_sescmd_history_length statistics in readwritesplit were moved into the core as service statistics. The session command history was moved into the MaxScale core in MaxScale 6 but the statistics were not updated to match this.

• Several redundant schemarouter statistics have been either replaced by statistics that are found in the general service statistics output or have been removed if they were irrelevant.

  • longest_sescmd_chain replaced by max_sescmd_history_length.

  • queries replaced with routed_packets.
• admin_readwrite_hosts and admin_readonly_hosts added. These settings limit the allowed source addresses for admin (REST-API) connections. See for more information.

• The alter commands in MaxCtrl now allow modifications to thetargets, servers, filters and cluster parameters for monitors and services. This makes it easier to define the exact set of servers that is to be used by a monitor or a service.

• The feature no longer requires modifying session_track_system_variables on the server. MaxScale adds last_gtid to the variable automatically for each session. Clients should not modify it manually.

• The now logs the execution of the binary protocol statements as text. This makes it so that for all execution of SQL, the query value in log_data will produce output.

• The functionality that the auth_all_servers parameter enabled is automatically enabled by the schemarouter whenever it is used.

For more details, please refer to:

The changelog for the previous MaxScale version can be found .

• The global setting skip_permission_checks has been deprecated and is ignored. Monitors start regardless of monitor user permissions.

• The uppercase versions of the slave_selection_criteria parameter in readwritesplit have been deprecated. All runtime modifications to the parameters are now saved using the lowercase versions.

• By default, readwritesplit will not replay transactions that are about to commit when transaction_replay is enabled. To retain the old behavior where transactions were always replayed, disable transaction_replay_safe_commit.

• Readwritesplit will now retry queries with partially returned results if they are done inside a transaction and transaction_replay is enabled.

• prune_sescmd_history now also performs history simplification by removing redundant executions of the same statement. This will reduce memory usage in the case when history repeats a small cycle of commands. One example of this is connection pools that prepare the connection with a small set of commands like SET NAMES and SET SQL_MODE.

• Common configuration settings can now be specified in a separate section, to be included by other sections.

• When changing the service password, the previous password will be retained and continue to be used if the new does not work.

• Embedded newlines are removed from logged messages.

• Schemarouter database map caches can be cleared with maxctrl call command schemarouter clear <service> where <service> is a service that uses the schemarouter.

• Schemarouter now allows stale cache entries to be used while the database map cache is being updated. By default the entries are usable for 150 seconds after they have gone stale. This limit can be configured with themax_staleness parameter.

• Added switchover-force command to MariaDB Monitor. This command performs a switchover even if primary server is unresponsive.

• Switchover now uses a longer command timeout on the old master. This should remove the need for adjusting monitor setting backend_read_timeout to get switchover to work.

• The NoSQL protocol now provides internal caching.

• Additional metadata is sent in the connection handshake. For more information, refer to the documentation.

• The connection_timeout parameter was renamed to wait_timeout to make the naming of the parameters the same in MaxScale and MariaDB server. The oldconnection_timeout parameter is now an alias to wait_timeout and its use has been deprecated. If used, a warning will be logged that the parameter is deprecated.

• The strip_db_esc parameter has been deprecated. The default behavior of stripping the escape characters is in all known cases the correct thing to do. Only broken legacy versions where the grants would be returned without backslash escaping would require this parameter to work.

• The Xpand monitor is now region aware.

• Passthrough authentication mode added to MariaDBAuth-module. See for more information.

• Added pam_mode=suid option to PamAuth module. This option separates the pam system library calls to a separate executable. See for more information. test_pam_login tool updated to support this mode.

• Added disk_space_ok option to MariaDB Monitor settings master_conditions and slave_conditions. Enabled by default in master_conditions. See for more information. Only available in MaxScale 23.08.5, 24.02.1 and later.

For more details, please refer to:

The changelog for the previous MaxScale version can be found .

This document describes the changes in release 23.02.15, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please see .

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Add MAXSCALE_USER and MAXSCALE_PASSWORD environment variables

Bug fixes

• MaxCtrl/REST-API should tell if password encryption is enabled

• MaxScale 24.02.6 is not compatible with MariaDB 12.0.2: Monitor fails with 'Cannot convert field ON to boolean'

• Upgrade Connector/C to 3.3.16 and 3.4.6

• Error 1047 when trying to run semi-sync replication through Maxscale

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the guide.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.13, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Early mismatched responses to session commands do not close connections

• Remove session_trace parameter from services section

• Session commands with max_slave_connections=0 after switchover do not discard stale connections

• The "INSERT INTO...RETURNING" syntax breaks causal_reads

• config sync does not ignore port for listeners

• config_sync_password infinitely doubles after maxscale restart & alter command

• The Contact view in the GUI has outdated information

• Relationship selections auto-cleared when creating a new monitor object

• readwritesplit enables multi-statements regardless of the state of causal_reads

• Cluster tree is not visualized accurately

• idle_session_pool_time=0s does not fairly share connections

• Need Documentation updates for Maxscale install recommendation

• MaxCtrl warnings are very verbose

• Errors during loading of users lack the service name

• maxctrl list queries fails

• Encrypted passwords cannot be used with maxctrl

• Log message: Unknown prepared statement handler given to MaxScale

• Backend connections with fail with EAGAIN

• Failed authentication warnings do not mention lack of client-side SSL as the reason of the failure

• MaxScale 24.02.04 not closing DB Connections properly

• Duration types that only take seconds return ms as units instead of s

• retry_failed_reads is not affected by delayed_retry_timeout

• list session in GUI shows wrong amount of sessions

• rebuild-server does not work with MariaDB 11.4

• Debug assertion on very large binary protocol prepared statements

• NVL and NVL2 are not detected as builtin functions outside of sql_mode=ORACLE

• Kafkacdc errors for wrong GTID positions are not clear

• Errors due to max_connections being exceeded are always fatal errors

• Certain special characters in the maxscale user causes async-rebuild-server to fail

• ed25519 socket droped when no user_mapping_file

• Resultset table not fully expanded for inactive query tab

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.10, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Add "enforce_read_only_servers" feature to MariaDB Monitor

Bug fixes

• 'Connection Busy' error causes empty schema tree explorer

• Master Stickiness state is not documented

• SQL API does not return binary data in resultsets

• admin_audit file name does not use log_dir value

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.4, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• GUI default value of inputs in the object creation dialog is empty after closing the dialog

• Session command response verification unnecessarily stores PS IDs for readconnroute

• Case-sensitiveness of enumerations is not documented

• Galeramon does not update replication lag of replicating servers

• Implement an option to switch to the old "ping" behaviour in MaxScale

• Connection init sql file execution can hang

• information_schema is not invalidated as needed

• qc_sqlite does not properly parse a RENAME statement

• Update maxscale.cnf default file

• Cache does not invalidate when a table is ALTERed, DROPed or RENAMEd

• SHOW TABLE STATUS FROM some_schema Fails with SchemaRouter

• GTID update may block the REST-API

• Binlogrouter treats GTID sequences as 32-bit integers

• Readwritesplit does not detect unrecoverable situations

• Update MaxGUI screenshots in the documentation

• Binlogrouter cannot write binlog files larger than 4GiB

• Binlogrouter runs out of memory on very large transactions

• Replication via binlogrouter temporarily blocks the REST-API

• MaxScale BinlogRouter skips large transactions causing data Inconsistency on attached slave

• Switchover fails with 'Unknown thread id' error

• Crash in mxs1687_avro_ha

• Binlogrouter eventually stops working if semi-sync replication is not used

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.3, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Provide a way to show details about all supported MaxScale modules via REST API and/or MaxCtrl

Bug fixes

• Detect ALTER EVENT failure on MariaDB 11.0

• ssl parameters specified on the bootstrap server are not copied to the rest

• Encrypted passwords are persisted in plaintext

• Session idleness diagnostic is wrong

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 23.02.2, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Query classifier does not classify XA transactions correctly.

• Partially executed multi-result queries are not treated as partial results

• Query classifier does not recognize BEGIN NOT ATOMIC ... END

• Query Editor: High memory usage when multiple statements are executed in a batch query

• Readwritesplit prefers idle primary over busy replicas

• Qlafilter logs responses from non-matched queries

• Query Editor doesn't quote identifier names properly

• AVX instructions end up being executed on startup

• Query canonicalization does not work on scientific numbers

• maxctrl classify sends malformed SQL

• transaction_replay_max_size default is 1GiB instead of 1MiB

• Passwords appear masked even if they are not set

• Undefined behavior in simd_canonical.cc

• I/O activity status missed on the Server current sessions

• Some configuration cause no errors to be logged

• Not all passwords were obfuscated in the maxctrl report

• Binlogrouter breaks if event size exceeds INT_MAX

• Maxscale ignores lower_case_table_names=1 on config file

• Regular expression documentation is inaccurate and lacking

• The statement canonicalizer cannot handle comments within statements

• KB pages reference mysqlauth and mysqlauth is deprecated for mariadbauth

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 22.08.18, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please see .

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Add MAXSCALE_USER and MAXSCALE_PASSWORD environment variables

Bug fixes

• MaxCtrl/REST-API should tell if password encryption is enabled

• MaxScale 24.02.6 is not compatible with MariaDB 12.0.2: Monitor fails with 'Cannot convert field ON to boolean'

• Upgrade Connector/C to 3.3.16 and 3.4.6

• Failing COM_STMT_PREPAREs that don't generate an ID aren't discarded from the history

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the guide.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 22.08.17, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Maxctrl interactive mode doesn't use --tls-verify-server-cert=false

• The logout screen is shown when accessing the MaxGUI login view.

• optimistic_trx causes a query to hang

• Processing of conditional headers is incorrect

• MaxCtrl fails to read large inputs from stdin

• admin_oidc_url is documented to not be dynamic when in fact it is

• REST-API always sends a Connection: close header

• Signal 11 crash when enabling causal reads with Galera

• Add a Service with a CLUSTER as its target breaks CONFIG SYNC

• Aborted connection on backend mariadb with persistpool maxscale

• Maxctrl config permission check error message is misleading

• Wrong password in interactive mode is only seen after the first command

• --secretsdir has no default value

• Using PKCS#1 private key in the REST-API results in cryptic errors

• Trailing parts of large session command are not routed correctly

• kafkacdc commits offsets when it probes GTIDs from Kafka

• Logs Archive page doesn't show useful API error

• Masking with functions uses wrong rule settings

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 22.08.16, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• Early mismatched responses to session commands do not close connections

• Remove session_trace parameter from services section

• Session commands with max_slave_connections=0 after switchover do not discard stale connections

• The "INSERT INTO...RETURNING" syntax breaks causal_reads

• config sync does not ignore port for listeners

• Documentation regarding mixing of cooperative_monitoring_locks and passive is unclear

• Relationship selections auto-cleared when creating a new monitor object

• readwritesplit enables multi-statements regardless of the state of causal_reads

• Cluster tree is not visualized accurately

• idle_session_pool_time=0s does not fairly share connections

• Need Documentation updates for Maxscale install recommendation

• MaxCtrl warnings are very verbose

• Errors during loading of users lack the service name

• maxctrl list queries fails

• Encrypted passwords cannot be used with maxctrl

• Log message: Unknown prepared statement handler given to MaxScale

• Backend connections with fail with EAGAIN

• Failed authentication warnings do not mention lack of client-side SSL as the reason of the failure

• MaxScale 24.02.04 not closing DB Connections properly

• Resultset is not selected automatically with Inactive query tabs

• Duration types that only take seconds return ms as units instead of s

• retry_failed_reads is not affected by delayed_retry_timeout

• list session in GUI shows wrong amount of sessions

• rebuild-server does not work with MariaDB 11.4

• Debug assertion on very large binary protocol prepared statements

• NVL and NVL2 are not detected as builtin functions outside of sql_mode=ORACLE

• Kafkacdc errors for wrong GTID positions are not clear

• Errors due to max_connections being exceeded are always fatal errors

• Certain special characters in the maxscale user causes async-rebuild-server to fail

• Resultset table not fully expanded for inactive query tab

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 22.08.13, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

New Features

• Add "enforce_read_only_servers" feature to MariaDB Monitor

Bug fixes

• Master Stickiness state is not documented

• ability to setup .secrets file location

• max_slave_connections=0 may create slave connections after a switchover

• ssl_version in MaxScale and tls_version in MariaDB behave differently

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 22.08.8, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

Bug fixes

• GUI default value of inputs in the object creation dialog is empty after closing the dialog

• Session command response verification unnecessarily stores PS IDs for readconnroute

• Case-sensitiveness of enumerations is not documented

• Galeramon does not update replication lag of replicating servers

• Implement an option to switch to the old "ping" behaviour in MaxScale

• Connection init sql file execution can hang

• information_schema is not invalidated as needed

• qc_sqlite does not properly parse a RENAME statement

• Update maxscale.cnf default file

• Cache does not invalidate when a table is ALTERed, DROPed or RENAMEd

• SHOW TABLE STATUS FROM some_schema Fails with SchemaRouter

• GTID update may block the REST-API

• Binlogrouter treats GTID sequences as 32-bit integers

• Readwritesplit does not detect unrecoverable situations

• Binlogrouter cannot write binlog files larger than 4GiB

• Binlogrouter runs out of memory on very large transactions

• Replication via binlogrouter temporarily blocks the REST-API

• Encrypted passwords are persisted in plaintext

• MaxScale BinlogRouter skips large transactions causing data Inconsistency on attached slave

• Switchover fails with 'Unknown thread id' error

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

This document describes the changes in release 21.06.19, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.

For any problems you encounter, please consider submitting a bug report on our Jira.

External CVEs resolved.

• Fixed by Container Image vulnerability CVE-2024-21538 (MXS)

Bug fixes

• Early mismatched responses to session commands do not close connections

• Session commands with max_slave_connections=0 after switchover do not discard stale connections

• The "INSERT INTO...RETURNING" syntax breaks causal_reads

• Documentation regarding mixing of cooperative_monitoring_locks and passive is unclear

Known Issues and Limitations

There are some limitations and known issues within this version of MaxScale. For more information, please refer to the document.

Packaging

RPM and Debian packages are provided for the supported Linux distributions.

Packages can be downloaded .

Source Code

The source code of MaxScale is tagged at GitHub with a tag, which is identical with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale is maxscale-X.Y.Z. Further, the default branch is always the latest GA version of MaxScale.

The source code is available .

_{This page is licensed: CC BY-SA / Gnu FDL}

This document lists known issues and limitations in MariaDB MaxScale and its plugins. Since limitations are related to specific plugins, this document is divided into several sections.

• Limitations and Known Issues within MariaDB MaxScale

  • Configuration limitations

    • Multiple MaxScales on same server

  • Security limitiations

    • MariaDB 10.2

  • MariaDB Default Values

  • Query Classification

  • Prepared Statements

  • Protocol limitations

    • Limitations with MySQL/MariaDB Protocol support (MariaDBClient)

  • Authenticator limitations

    • Limitations in the GSSAPI authenticator

    • Limitations in the MySQL authenticator (MariaDBAuth)

  • Filter limitations

    • Database Firewall limitations (dbfwfilter)

    • Tee filter limitations (tee)

  • Monitor limitations

    • Limitations with Galera Cluster Monitoring (galeramon)

  • Router limitations

Configuration limitations

In versions 2.1.2 and earlier, the configuration files are limited to 1024 characters per line. This limitation was increased to 16384 characters in MaxScale 2.1.3. MaxScale 2.3.0 increased this limit to 16777216 characters.

In versions 2.2.12 and earlier, the section names in the configuration files were limited to 49 characters. This limitation was increased to 1023 characters in MaxScale 2.2.13.

Multiple MaxScales on same server

Starting with MaxScale 2.4.0, on systems with Linux kernels 3.9 or newer due to the addition of SO_REUSEPORT support, it is possible for multiple MaxScale instances to listen on the same network port if the directories used by both instances are completely separate and there are no conflicts which can cause unexpected splitting of connections. This will only happen if users explicitly tell MaxScale to ignore the default directories and will not happen in normal use.

Security limitiations

MariaDB 10.2

The parser of MaxScale correctly parses WITH statements, but fails to collect columns, functions and tables used in the SELECT defining the WITH clause.

Consequently, the database firewall will not block WITH statements where the SELECT of the WITH clause refers to forbidden columns.

MariaDB Default Values

MaxScale assumes that certain configuration parameters in MariaDB are set to their default values. These include but are not limited to:

• autocommit: Autocommit is enabled for all new connections.

• tx_read_only: Transactions use READ WRITE permissions by default.

Query Classification

Follow the Jira issue to track the progress on this limitation.

XA transactions are not detected as transactions by MaxScale. This means that all XA commands will be treated as unknown commands and will be treated as operations that potentially modify the database (in the case of readwritesplit, the statements are routed to the master).

MaxScale will not track the XA transaction state which means that any SELECT queries done inside an XA transaction can be routed to servers that are not part of the XA transaction.

This limitation can be avoided on the client side by disabling autocommit before any XA transactions are done. The following example shows how a simple XA transaction is done via MaxScale by disabling autocommit for the duration of the XA transaction.

Prepared Statements

For its proper functioning, MaxScale needs in general to be aware of the transaction state and autocommit mode. In order to be that, MaxScale parses statements going through it.

However, if a transaction is commited or rolled back, or the autocommit mode is changed using a prepared statement, MaxScale will miss that and its internal state will be incorrect, until the transaction state or autocommit mode is changed using an explicit statement.

For instance, after the following sequence of commands, MaxScale will still think autocommit is on:

To ensure that MaxScale functions properly, do not commit or rollback a transaction or change the autocommit mode using a prepared statement.

Protocol limitations

Limitations with MySQL/MariaDB Protocol support (MariaDBClient)

• Compression is not included in the server handshake.

• If a KILL [CONNECTION] <ID> statement is executed, MaxScale will intercept it. If the ID matches a MaxScale session ID, it will be closed, similarly to how MariaDB does it. If the KILL CONNECTION USER <user> form is given, all connections with a matching username will be closed.

• MariaDB MaxScale does not support KILL QUERY ID <query_id> type statements. If a query by a query ID is to be killed, it needs to be done directly on the backend databases.

Authenticator limitations

Limitations in the GSSAPI authenticator

Currently, MariaDB MaxScale only supports GSSAPI authentication when the backend connections use GSSAPI authentication. Client side GSSAPI authentication with a different backend authentication module is not supported.

Limitations in the MySQL authenticator (MariaDBAuth)

• MySQL old style passwords are not supported. MySQL versions 4.1 and newer use a new authentication protocol which does not support pre-4.1 style passwords.

• When users have different passwords based on the host from which they connect MariaDB MaxScale is unable to determine which password it should use to connect to the backend database. This results in failed connections and unusable usernames in MariaDB MaxScale.

• Only a subset of netmasks are supported for the Host-column in the mysql.user-table (and related tables). Specifically, if the Host is of the form base_ip/netmask, then the netmask must only contain the numbers 0 or 255. For example, a netmask of 255.255.255.0 is fine while 255.255.255.192 is not.

Filter limitations

Database Firewall limitations (dbfwfilter)

The Database Firewall filter does not support multi-statements. Using them will result in an error being sent to the client.

Tee filter limitations (tee)

The Tee filter does not support binary protocol prepared statements. The execution of a prepared statements through a service that uses the tee filter is not guaranteed to succeed on the service where the filter branches to as it does on the original service.

This possibility exists due to the fact that the binary protocol prepared statements are identified by a server-generated ID. The ID sent to the client from the main service is not guaranteed to be the same that is sent by the branch service.

Monitor limitations

A server can only be monitored by one monitor. Two or more monitors monitoring the same server is considered an error.

Limitations with Galera Cluster Monitoring (galeramon)

The default master selection is based only on MIN(wsrep_local_index). This can be influenced with the server priority mechanic described in the Galera Monitor manual.

Router limitations

Refer to individual router documentation for a list of their limitations.

Release 2.5.28 is a GA release.

Released: 21 Aug 2023

This document describes the changes in release 2.5.28, when compared to the previous release in the same series.

If you are upgrading from an older major version of MaxScale, please read the upgrading document for this MaxScale version.