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Configuring parameters for a database pool
The following table describes the primary parameters of a database pool and the
recommended value for each parameter:
Parameter Description and recommended value
initsize When a JVM is created and connection pool objects are instantiated
for each of the pools, a call is made to the JDBC driver for each
pool and an initial number of connections are created for each
pool. Connections that are created from the initsize are part of
the connections that exist in the pool for reuse, as needed.
Since various JVMs can load the initial number of connections, but
might not really need them, it is recommended that you do not set
the initsize to a large value.
Default value: 0 or 1
Recommended value: 1
maxsize Maximum size of the connection pool that pertains to a database
pool. After a connection is created up to this value, it is not
deleted. It remains idle until needed.
Buffersize Maximum number of connections that can be created. Connections
that are created beyond the maxsize value are created and deleted
as needed.
After all the connections are used (maxsize + buffersize), and a
new request for a connection comes in, the new request is denied,
and an error is written stating that a connection cannot be created
and that the connection pool is exhausted.
maxConn This parameter is not used in Sterling B2B Integrator.
Frequently asked questions
v Q: How many connections will I need?
A: You can start with the recommended settings provided by the tuning wizard
and then monitor the noapp.log file to ensure that you are not close to the
maximum size of the connection pool (maxsize). Monitor the usage over a
period of time and observe if the usage is increasing. If the usage limits exceed
25% of the settings that are recommended by the tuning wizard and the demand
for connections is increasing, contact the IBM Professional Services onsite
consultant or IBM Customer Support.
v Q: Why are connections shown as being idle?
A: Getting a new connection from the database is expensive. Connections are
held in a pool to be available when the system needs them, which means that
connections are often shown as being idle. This method is a performance
trade-off that enables connections to be available when needed.
v Q: Can I kill idle connections?
A: Configure the pool to keep fewer connections, and release connections after a
specified amount of time.
Schema objects
This topic covers the following concepts:
v Placement of Schema Table Objects
18 Sterling B2B Integrator: Performance Management