In HiRDB, a UAP of a single HiRDB client can connect simultaneously to multiple HiRDB servers. This is called the multi-connection facility. The multi-connection facility enables a single UAP at a HiRDB client to make multiple connections to a single HiRDB server. A single UAP can also connect to multiple HiRDB servers. Each of the multiple connections is treated as an independent transaction (that is, it is handled by the HiRDB server as though each connection were made from a separate UAP). Because a single UAP can make multiple connections, the number of UAPs to be executed can be reduced, thus reducing the overall memory requirements of the UAPs.

To use the multi-connection facility, a dedicated library that is provided must be linked. For details about the multi-connection facility, see the HiRDB Version 9 UAP Development Guide.

Connection modes that can use the multi-connection facility

The multi-connection facility can be used under transaction control unique to HiRDB, as well as under transaction control based on the XA interface. However, the multi-connection facility used in linkage to OLTP by means of the XA interface requires different items to be specified when HiRDB is registered into the transaction manager. For details on the registration procedure, see the HiRDB Version 9 Installation and Design Guide.

Setting up the multi-connection facility

The multi-connection facility is used by defining the following SQLs in the UAP definition:

• Allocation of a connection handle (ALLOCATE CONNECTION HANDLE statement)
• Declaration of connection handle setup (DECLARE CONNECTION HANDLE SET statement)
• Cancellation of connection handle setup (DECLARE CONNECTION HANDLE UNSET statement)
• Release of connection handle (FREE CONNECTION HANDLE statement)