Chapter 14. Jdbc Connection Concentrator And Workload Balancing - IBM DB2 Manual

Chapter 14. JDBC connection concentrator and workload
balancing
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© Copyright IBM Corp. 1998, 2008
Java applications that use IBM Data Server Driver for JDBC and SQLJ type 4
connectivity to access DB2 for z/OS or IBM Informix Dynamic Server can take
advantage of the connection concentrator and workload balancing functions.
The IBM Data Server Driver for JDBC and SQLJ connection concentrator and
workload balancing functions are similar to the connection concentrator and
workload balancing functions of DB2 Connect.
The IBM Data Server Driver for JDBC and SQLJ connection concentrator function
can reduce the resources that DB2 for z/OS or IBM Informix Dynamic Server data
sources require to support large numbers of client applications. The IBM Data
Server Driver for JDBC and SQLJ connection concentrator function lets many
connection objects use the same physical connection, which reduces the total
number of physical connections to the data source.
Workload balancing advantages for DB2 for z/OS: IBM Data Server Driver for
JDBC and SQLJ workload balancing can improve availability of a data sharing
group. When workload balancing is enabled, the driver gets frequent status
information about the members of a data sharing group. The driver uses this
information to determine the data sharing member to which the next transaction
should be routed. With workload balancing, the DB2 for z/OS server and
Workload Manager for z/OS (WLM) ensure that work is distributed efficiently
among members of the data sharing group and that work is transferred to another
member of a data sharing group if one member has a failure.
Workload balancing advantages for IBM Informix Dynamic Server: IBM Data
Server Driver for JDBC and SQLJ workload balancing can improve availability of a
high-availability cluster. When workload balancing is enabled, the driver gets
frequent status information about the servers the cluster. The driver uses this
information to determine the server to which the next transaction should be
routed. With workload balancing, the Connection Manager ensures that work is
distributed efficiently among servers in the cluster and that work is transferred to
another server if one server has a failure.
The IBM Data Server Driver for JDBC and SQLJ uses transport objects and a global
transport objects pool to support the connection concentrator and workload
balancing. There is one transport object for each physical connection to the data
source. When you enable the connection concentrator and workload balancing, you
set the maximum number of physical connections to the data source at any point
in time by setting the maximum number of transport objects.
At the driver level, you set limits on the number of transport objects using IBM
Data Server Driver for JDBC and SQLJ configuration properties.
At the connection level, you can use DataSource properties to enable and disable
the IBM Data Server Driver for JDBC and SQLJ connection concentrator and
workload balancing and set limits on the number of transport objects. You can set
these properties when you obtain a connection using the DataSource interface or
the DriverManager interface.
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