xSQL Cluster Control

The following sections demonstrate a set of cluster control commands are provided by xSQL to get information from, detach and attach cluster nodes.

For an overview see page xSQL Commands

Cluster info

The cluster info command shows a list of the current cluster nodes and their states. For example:

 
    XSQL>cluster info
    NodeId           Address                          QRank     State
    *    0        127.0.0.1:15000                       100     Online
     1        127.0.0.1:5001                          1     Offline
     2        127.0.0.1:15001                         1     Offline
     6        127.0.0.1:15005                         1     Online
     

The same information can also be displayed using the function mco_cluster_info() with an SQL select statement:

 
    XSQL>select mco_cluster_info();
    NodeId           Address                          QRank     State
    *    0        127.0.0.1:15000                       100     Online
     1        127.0.0.1:5001                          1     Offline
     2        127.0.0.1:15001                         1     Offline
     6        127.0.0.1:15005                         1     Online
     

Detach

The detach command disconnects a database from the cluster. The database then becomes unavailable for both reading and writing. For example:

 
    XSQL>cluster detach
    Successfully detached
     

The database can also be detached using the function mco_cluster_detach() with an SQL select statement:

 
    XSQL>select mco_cluster_detach();
    Successfully detached
     

Attach

The attach command reconnects a database to the cluster after a previous detach. The database then becomes available for both reading and writing. For example:

 
    XSQL>cluster attach
    Successfully attached
     

The database can also be attached using the function mco_cluster_attach() with an SQL select statement:

 
    XSQL>select mco_cluster_attach();
    Successfully attached