Description

The @Promote system procedure promotes a replica database to normal operation. During database replication, the replica database only accepts input from the master database. If, for any reason, the master database fails and replication stops, you can use @Promote to change the replica database from a replica to a normal database. When you invoke the @Promote system procedure, the replica exits read-only mode and becomes a fully operational VoltDB database that can receive and execute both read-only and read/write queries.

Note that once a database is promoted, it cannot return to its original role as the receiving end of database replication without first stopping and reinitializing the database as a replica. If the database is not a replica, invoking @Promote returns an error.

Return Values

Returns one VoltTable with one row.

Examples

The following programming example promotes a database cluster.

client.callProcedure("@Promote");

It is also possible to promote a replica database using sqlcmd or the voltadmin promote command. The following commands are equivalent:

$ sqlcmd
1> exec @Promote;

$ voltadmin promote