Creating a member subset

To create member subsets, use the WLM_CREATE_MEMBER_SUBSET system routine.

To create the member subset:

1. Connect to the database. For example:

   db2 CONNECT TO BANKDB

2. Create the member subset. For example:

   CALL SYSPROC.WLM_CREATE_MEMBER_SUBSET('OLTP_SUBSET', '<databaseAlias>OLTP_DB</databaseAlias>', '( 0, 1, 2 )')

   where:

   • M0, M1, and M2 are members in the Db2® data server environment.
   • OLTP_SUBSET is the name of the member subset.
   • OLTP_DB is a database alias name that is not currently cataloged in the Db2 data server system database directory.

   WLM_CREATE_MEMBER_SUBSET is autonomous, so after invoking the routine there is no need to issue a COMMIT or ROLLBACK command.
3. Validate that the database alias is cataloged in the Db2 data servers system database directory.

   db2 LIST DATABASE DIRECTORY

   Verify that the database alias is listed. For example:

    Database alias                       = OLTP_DB
    Database name                        = BANKDB

4. For applications that you want to be assigned to this member subset, ensure that they are configured to connect to the database alias OLTP_DB. Ensure that the applications are configured to connect to the database alias OLTP_DB instead of the database name BANKDB.
5. Verify the connection by querying the member subset. This command must be run from an application that is connected over TCP/IP to OLTP_DB.

    SELECT M.SUBSETNAME
    FROM SYSCAT.MEMBERSUBSETS AS M,
    TABLE(MON_GET_CONNECTION
    (MON_GET_APPLICATION_HANDLE(), -1 ))
    AS CONN WHERE M.SUBSETID = CONN.MEMBER_SUBSET_ID

6. Verify that the server list cache for the OLTP_SUBSET subset contains server addresses for each member that is included in the subset. If the member subset was created in a Db2 pureScale® environment and is defined as inclusive, there should be a server address for each member in the cluster that is not in the OLTP_SUBSET subset; each of these addresses should have a reported PRIORITY of 0.

   SELECT * FROM TABLE
      (MON_GET_SERVERLIST(2))
      AS SERVERLIST