API functions that can be called from the application's HA monitor to monitor the operational status of the TFServers. Mirroring can also be used to support maintaining multiple copies of a database in which updates are only made to the master but readers are directed to one of the mirrored slaves in order to distribute many possible database readers across multiple computers. In this situation, it is not necessary for the master to wait for each slave to confirm a successful commit of each transaction and the mirroring process can run asynchronously. RDM database mirroring requires that the master and all mirrored databases be maintained on the same computer/operating system platforms. Database replication This is due to be released in Q2/18. Replication is similar to mirroring but it not really intended for HA support but for transferring all or, more likely, portions of one database (master) to another database (slave). Replication is designed to work where the databases are not necessarily being maintained on the same platform. The slave databases can be other RDM-managed databases or they can be a 3rd-party DBMS. RDM's replication includes support for multiple master to single slave selective replication of circular table data—important for embedded computers and devices at the edge of the data grid where status and condition monitoring occurs. The status data stored in each master's circular table is replicated to a central control system maintaining a permanent history of all device statuses, which can then be made available for a variety of time series and other analyses. RDM also provides a database change notification API library that allows a slave to access the master replication logs without the data be stored and managed in a database. This allows, for example, a master to store device control information in a database that is replicated to the device through the notification API in order to efficiently control device operation. SQL/PL The RDM SQL Programming Language (SQL PL) is based on the ansi/ISO SQL Persistent Stored Modules (PSM) specification (ISO/IEC 90756-4:2011 +2012). It provides a high-level language in which stored procedures and functions can be written, compiled and called within the RDM SQL system. SQL PL is a computationally complete programming language for use in RDM SQL stored routines (procedures or functions). The language is block structured with the ability to declare variables that conform to the usual scoping rules with an assignment statement so