In order to enable DRCP, the connection
broker needs to be started. The following command
starts the broker, which registers itself with the database
listener from sys user:
Once the pool is started, it remains in
this state until it is explicitly stopped. The pool is
automatically restarted if it is active when the database
instance is restarted.
In order for the client connections to
use the connection pool, the connect string must specify the
connect type as POOLED. For example, the TNS connect
descriptor to use DRCP for client connections could be:
The DRCP pool can be stopped when all
client requests managed by DRCP have completed using the
following command from sys user:
SQL> execute dbms_connection_pool.stop_pool();
Considerations with DRCP
Since the pooled servers are essentially
a pool of preserved dedicated servers, there are certain
special considerations that apply to the use of DRCP in the
Modifying database users of DRCP - Since pooled servers are dedicated servers owned by the
user, it is not possible to change the password of a user
while that user is connected. Also, when dropping a
user, make sure that no sessions authenticated by that
user are in the pool.
Shutting down the database - When
client connections are actively being handled by DRCP, the
database needs to wait until all pooled servers are
returned to the connection broker before stopping the pool
and shutting down the database.
Advanced Security Option (ASO) - ASO
options are not available for pooled servers.
Oracle 11g has provided several dynamic
views for monitoring database resident connection pooling
dba_cpool_info - Contains information about the
connection pool including the maximum and minimum number
of connections, pool status, and timeout for idle
- Contains pool statistics including the number of session
requests, the total wait time for a session request, and
the number of times a session that matches the request was
found in the pool.
- Contains connection-class level statistics for the pool.