Release Notes for MariaDB MaxScale 22.08.1

Logging Behavior

• Default logging behavior has changed: (MXS-4192)

  • Prior to this release, by default MaxScale logs to syslog in addition to the MaxScale log.

  • Starting with this release, by default MaxScale only logs to the MaxScale log and no longer logs to syslog.

  • To retain the behavior of prior releases, in your MaxScale configuration, under the [maxscale] section, specify syslog=true:

    [maxscale]
    syslog=true
    

Group Change Handling with Xpand Monitor (xpandmon)

• Xpand Monitor (xpandmon) handles Xpand Group Changes explicitly. (MXS-3490)

  • Prior to this release, Xpand Monitor treats Group Change errors in the same way as any other error, so the monitor would abandon the current node and try to connect to other nodes. Xpand Monitor would repeatedly attempt to connect to nodes at regular intervals until the Group Change ended.

  • Starting with this release, Xpand Monitor detects when a monitor operation fails due to a Group Change. Xpand Monitor sets the state of all nodes to "Down" until the Group Change is completed to prevent other components (such as routers) from attempting to take corrective action before the Group Change really is over. During the Group Change, the monitor will not log errors related to it not being able to connect to Xpand, as that is to be expected until the Group Change is over.

  • When a Group Change begins, the monitor writes the following message to the MaxScale log:

    Group change detected.
    

  • When a query is executed during a Group Change and log_info is enabled, the monitor writes the following message to the MaxScale log:

    MONITOR_NAME: Group Change detected on NODE_NAME: NODE_QUERY_RESPONSE_TEXT
    

  • When a Group Change finishes, the monitor writes the following message to the MaxScale log:

    Group change now finished.
    

Rebuild Server with MariaDB Monitor (mariadbmon)

• MariaDB Monitor (mariadbmon) can use MariaDB Enterprise Backup (mariadb-backup) to clone the contents of a server. (MXS-2542)

• The rebuild operation is a monitor module command that can be launched with MaxCtrl

• The rebuild operation replaces the contents of a database server with the contents of another server.

• MariaDB Monitor performs this operation by running MariaDB Enterprise Backup on both the source and target servers using SSH.

• For example, to rebuild a replica node, execute maxctrl call command mariadbmon async-rebuild-server:

  maxctrl call command mariadbmon async-rebuild-server MONITOR_NAME TARGET_NODE [ SOURCE_NODE ]
  

  • Replace MONITOR_NAME with the name of the monitor.

  • Replace TARGET_NODE with the name of the target node.

  • Optionally, replace SOURCE_NODE with the name of the source node. If the source node is not specified, then a source node is auto-selected. When auto-selecting, the monitor prefers to pick an up-to-date replica server.

• For additional information, see "Rebuild a Replica Node with MariaDB Enterprise Server".

ColumnStore Commands with MariaDB Monitor (mariadbmon)

• MariaDB Monitor (mariadbmon) can execute commands for MariaDB Enterprise ColumnStore. (MXS-3217)

• MariaDB Monitor can fetch cluster status, add and remove nodes, start and stop the cluster, and set the cluster read-only or read-write.

• To execute the commands, execute maxctrl call command mariadbmon COMMAND_NAME PARAMETERS

• For additional information, see "MariaDB Monitor: ColumnStore Commands".

MaxGUI Enhancements

Support has been added to MaxGUI for:

• Columnstore operations (MXS-3216)

• Drag and drop control of replication (MXS-3642)

• Killing a session (MXS-4087)

• Managing MaxScale users (updating, adding, deleting MaxScale users) (MXS-3853)

• Multiple query tabs within the Worksheet, so multiple queries can be run from one worksheet (MXS-4025)

• Saving and editing .sql files in the Query Editor (MXS-3723)

• Showing filter diagnostics (MXS-4167)

• Storing queries as snippets in the Query Editor (MXS-3725)

Additionally, the MaxGUI user interface has been enhanced:

• The user interface indicates when operations are unavailable due to lack of privileges. (MXS-3783)

• A "Stop Query" button is included in the Query Editor. (MXS-3918)

Dynamic Reload of SSL/TLS Certificates

• SSL/TLS certificates can be updated without server restart: (MXS-3982) (MXS-4041)

  • The new maxctrl reload tls command reloads the TLS certificates of servers, listeners, and the REST API.

  • Prior to this release, changes to certificates required restart of MaxScale.

Automatic Purge

• Avrorouter (avrorouter) can automatically purge old files. (MXS-4010)

• The max_data_age parameter has been added to configure this functionality. The parameter can be set to a time duration.

• The default value for the max_data_age parameter is 0s (0 seconds), which means that old files are not automatically purged.

• When the max_data_age parameter is set to a duration greater than 0s (0 seconds), the Avrorouter (avrorouter) will automatically purge any files that only have data that is older than the specified duration. This means that all data files with at least one event that is newer than the configured limit will not be removed, even if the ages of all the other events are above the limit.

• Purge operations are only done when a file rotation takes place (either manual or automatic) or when a schema change is detected.

• MariaDB recommends configuring the max_data_age and max_file_size parameters together to provide automatic removal of stale data.

• Automatic file purging only works with the direct replication mode. The legacy file based replication mode does not support this.

File Rotation

• Avrorouter (avrorouter) can automatically rotate files based on file size. (MXS-4010)

• The max_file_size parameter can be used to configure this functionality. This parameter can be set to a file size limit.

• The default value for the max_file_size parameter is 0, which means that files are not automatically rotated based on file size.

• When the size of a single Avro data file exceeds the configured value of the max_file_size parameter, the Avrorouter (avrorouter) rotates the file and creates a new file. This is done by closing the existing file and creating a new one with the next version number. This uses the size of the file as reported by the operating system. The check for the file size is done after a transaction has been processed which means that large transactions can still cause the file size to exceed the given limit.

• File rotation only works with the direct replication mode. The legacy file based replication mode does not support this.

Causal Reads

• Support added for causal reads in a multi-MaxScale environment using the Read/Write Split Router (readwritesplit) with the causal_reads parameter.

• Previous releases supported causal reads only in a single MaxScale environment. (MXS-3663)

• For additional information, see "Ensuring Causal Consistency with MaxScale's Read/Write Split Router".

Disable JSON Schema Updates

• Kafka CDC Router (kafkacdc) can be configured to skip sending schema updates. (MXS-4052)

• The send_schema parameter can be used to configure this functionality.

• The default value for the send_schema parameter is true, which means that a JSON schema object is sent in the stream whenever the table schema changes.

• When the send_schema parameter is false, a JSON schema object is not sent in the stream whenever the table schema changes.

Multi-MaxScale

• The nosqlprotocol protocol module can be used in a multi-MaxScale setup. (MXS-4145)

Implicit Bootstrapping

• The nosqlprotocol protocol module can optionally create a default NoSQL user at startup. (MXS-4242)

• Starting with this release, authentication and authorization for NoSQL Listeners can be implicitly bootstrapped.

• Implicit bootstrapping occurs at startup when there are no NoSQL users in the account database, and the following parameters are configured:

  • Authentication and authorization are configured by setting the nosqlprotocol.authentication_required and nosqlprotocol.authorization_enabled parameters to true

  • The database user account for authentication and authorization is configured by setting the nosqlprotocol.user and nosqlprotocol.password parameters

  • For example, the following example configuration shows the parameters required for implicit bootstrapping:

    [SERVICE_NAME]
    type=service
    ...
    
    [LISTENER_NAME]
    type=listener
    service=SERVICE_NAME
    protocol=nosqlprotocol
    port=17017
    nosqlprotocol.authentication_required=true
    nosqlprotocol.authorization_enabled=true
    nosqlprotocol.user=USER_NAME
    nosqlprotocol.password=USER_PASSWORD
    

• When implicit bootstrapping occurs at startup, the nosqlprotocol protocol module performs the following procedure:

  1. The nosqlprotocol protocol module waits until the primary server used by the service linked to the NoSQL Listener is available.

  2. The nosqlprotocol protocol module connects to the primary server using the database user account specified by the nosqlprotocol.user and nosqlprotocol.password parameters.

  3. The nosqlprotocol protocol module executes SHOW GRANTS to determine the user account's database privileges.

  4. The nosqlprotocol protocol module translates the user account's database privileges into the equivalent NoSQL role.

  5. The nosqlprotocol protocol module creates a NoSQL user in the account database.

• After implicit bootstrapping occurs, the credentials specified by the nosqlprotocol.user and nosqlprotocol.password parameters can be used to connect to the NoSQL Listener. The nosqlprotocol protocol module only uses the nosqlprotocol.user and nosqlprotocol.password parameters during implicit bootstrapping, so they can be removed from the configuration after bootstrapping has occurred.

Destroy Session

• The new maxctrl destroy-session command is available for killing a session. (MXS-3152)

• The new command requires the session ID to be specified. The session ID can be obtained using maxctrl list sessions.

• Prior to this release, to kill a session, a direct connection to the database must be made, and the KILL statement must be executed.

Memory Usage

• The maxctrl list sessions and maxctrl show session commands provide information about the memory usage of a session. (MXS-2724)

  • Prior to this release, the commands provide no memory usage information.

  • Starting with this release, the commands provide information that can be used for detecting anomalous behavior.

  • Example output:

    ├───────────────────┼──────────────────────────────────┤
    │ Memory            │ {                                │
    │                   │     "connection_buffers": 67226, │
    │                   │     "last_queries": 0,           │
    │                   │     "session_history": 774,      │
    │                   │     "total": 68000,              │
    │                   │     "variables": 0               │
    │                   │ }                                │
    └───────────────────┴──────────────────────────────────�
    

Reload

• The new maxctrl reload session and maxctrl reload sessions commands are available to reload existing sessions. (MXS-2347)

• Session reload enables an existing session to use servers added since the session was started. By default, sessions use servers present at the time the session was started. With this feature, sessions for long-running client connections can use servers added since the session was started.

• maxctrl reload session SESSION_ID reloads the session with the specified session ID.

• maxctrl reload sessions reloads all sessions.

Database Firewall Filter (dbfwfilter) Removal

• Previously deprecated in MaxScale 6, the Database Firewall Filter (dbfwfilter) has been removed in MaxScale 22.08.

Removed Parameters

The following MariaDB Monitor (mariadbmon) parameters have been removed:

Deprecated Parameters