Quiescing a database

This topic illustrates the behavior that WebSphere Message Broker expects when a database is quiesced. A database administrator issues the quiesce instruction on a database; it is not a function of the broker.

This topic assumes three things about the database being quiesced:
  • The database can be quiesced
  • New connections to the database are blocked by the database when it is quiescing
  • Message flows using the database eventually become idle
The following list shows the behavior expected while a database is quiescing:
  1. Tell the database to quiesce. As soon as you tell database to quiesce, connections that are in use remain in use, but no new connections to the database are allowed.
  2. Processing messages. Messages that are using existing connections to the database continue to use their connection until the connection becomes idle. This can take a long time if messages continue to be processed. To ensure that messages are no longer processed, stop the message flow. Stopping the message flow stops messages being processed and releases the database connections that the flow was using. This ensures that the database connections that the flow holds become idle.
  3. Database connections for the message flow become idle. This causes the broker to release the connections to the user databases that the message flow is using. When all connections to the database from the broker and from any other applications using the database are released, the database can complete its quiesce function.
Related tasks
Preparing databases on UNIX systems
Creating a DB2 database on Windows
Creating a DB2 database on Linux and UNIX systems
Customizing DB2 databases
Connecting to the databases
Authorizing access to the databases
Related reference
User database connections
Supported databases
Listing database connections that the broker holds
WebSphere MQ connections