Limitations in Azure Database for MariaDB

The following sections describe capacity, storage engine support, privilege support, data manipulation statement support, and functional limits in the database service.

Server parameters

Note

If you are looking for min/max values for server parameters like max_connections and innodb_buffer_pool_size, this information has moved to the server parameters article.

Azure Database for MariaDB supports tuning the values of server parameters. The min and max value of some parameters (ex. max_connections, join_buffer_size, query_cache_size) is determined by the pricing tier and vCores of the server. Refer to server parameters for more information about these limits.

Upon initial deployment, an Azure for MariaDB server includes systems tables for time zone information, but these tables are not populated. The time zone tables can be populated by calling the mysql.az_load_timezone stored procedure from a tool like the MySQL command line or MySQL Workbench. Refer to the Azure portal or Azure CLI articles for how to call the stored procedure and set the global or session-level time zones.

Password plugins such as "validate_password" and "caching_sha2_password" are not supported by the service.

Storage engine support

Supported

Unsupported

Privileges & data manipulation support

Many server parameters and settings can inadvertently degrade server performance or negate ACID properties of the MariaDB server. To maintain the service integrity and SLA at a product level, this service does not expose multiple roles.

The MariaDB service does not allow direct access to the underlying file system. Some data manipulation commands are not supported.

Privilege support

Unsupported

The following are unsupported:

  • DBA role: Restricted. Alternatively, you can use the administrator user (created during new server creation), allows you to perform most of DDL and DML statements.
  • SUPER privilege: Similarly, SUPER privilege is also restricted.
  • DEFINER: Requires super privileges to create and is restricted. If importing data using a backup, remove the CREATE DEFINER commands manually or by using the --skip-definer command when performing a mysqldump.
  • System databases: The mysql system database is read-only and used to support various PaaS functionality. You cannot make changes to the mysql system database.
  • SELECT ... INTO OUTFILE: Not supported in the service.

Supported

  • LOAD DATA INFILE is supported, but the [LOCAL] parameter must be specified and directed to a UNC path (Azure storage mounted through SMB).

Functional limitations

Scale operations

  • Dynamic scaling to and from the Basic pricing tiers is currently not supported.
  • Decreasing server storage size is not supported.

Server version upgrades

  • Automated migration between major database engine versions is currently not supported.

Point-in-time-restore

  • When using the PITR feature, the new server is created with the same configurations as the server it is based on.
  • Restoring a deleted server is not supported.

Subscription management

  • Dynamically moving pre-created servers across subscription and resource group is currently not supported.

VNet service endpoints

  • Support for VNet service endpoints is only for General Purpose and Memory Optimized servers.

Storage size

  • Please refer to pricing tiers for the storage size limits per pricing tier.

Current known issues

  • MariaDB server instance displays the incorrect server version after connection is established. To get the correct server instance engine version, use the select version(); command.

Next steps