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:
- Tell the database to quiesce. As soon as you tell the database
to quiesce, the connections that are in use remain in use, but no
new connections to the database are allowed.
- Processing messages. Messages that are using existing connections
to the database continue to use their connections until the connections
become 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.
- 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.
For more information, see User database connections.