The scope of configuration keywords and their associated values are defined by the position of configuration keywords in the IBM® data server driver configuration file (db2dsdriver.cfg file).
You can define two subsections under the database information section to enable high availability features:
In Version 10.1 Fix Pack 2 and later fix packs, you can define the <specialregisters> subsection in the <dsn>, <database>, or <parameters> sections of the db2dsdriver.cfg file. The special registers subsection is contained within the <specialregisters> and </specialregisters> tags. The special registers that are defined in the <specialregisters> subsection are sent to the server when the first SQL statement is sent by the client after a connection is established. All special registers that are specified in the <specialregisters> subsection are executed after processing other existing special register keywords that are defined in the connection string, the IBM data server driver configuration file, or the db2cli.ini file. Therefore, if a special register is specified in the <specialregisters> subsection and also specified in the connection string, the IBM data server driver configuration file or the db2cli.ini file, the value that is set in the <specialregisters> subsection is the effective value. The special registers subsection can be placed in the <dsn>, <databases>, or <parameters> sections of the IBM data server driver configuration file.
The <specialregisters> subsection has no performance impact and does not result in additional network traffic. Any exceptions that are encountered are reported for the SQL statement.
All special register parameters that are defined in the <specialregisters> subsection are replayed during the failover scenario that is associated with the automatic client reroute feature.
For a list of the special registers that can be specified for connections to DB2® for z/OS® servers, see "General rules for special registers".
If you specify multiple entries of the same parameter, with different values, in the same section of an IBM data server driver configuration file, you cannot determine which parameter value takes effect.