If you access databases from one or more message flows,
your database administrator might occasionally want to issue the quiesce
instruction on a database. This action is a function of the database,
not of the integration node.
The following three assumptions are made
for the database that you are quiescing:
- The database can be quiesced (not all databases support this function).
- New connections to the database are blocked by the database when
it is quiescing.
- Message flows that access the
database eventually become idle.
The following list shows the behavior that is expected
while a database is quiescing:
- Run the command that quiesces the database. When this command
starts, the connections that are in use remain in use, but no new
connections to the database are allowed.
- Messages that are being processed by message flows, which use
existing connections to the database, continue to use their connections
until the connections become idle. Therefore if messages continue
to be received by the message flow, it might be a long time before
the quiesce occurs. 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 action ensures that the database connections that the
flow holds become idle.
- Database connections for the message flow become idle. This situation
causes the integration node to release the connections to the databases that the message flow is using. When all connections to
the database from the integration node, and from any other applications that are using
the database, are released, the database can complete its quiesce
function.
For more information, see Database connections.