The data compression facility enables you to compress user data that is sent over the network by an RPC. You can use this facility to reduce the number of packets that are sent over the network, thereby reducing network congestion.

You use the dccltdatacomp operand in the TP1/Client/J environment definition to specify whether or not the data compression facility is used.

When this facility is used, TP1/Client/J compresses the value of the input parameter (in_data) set by the rpcCall method that is executed from a CUP. If compression is effective, the compressed data is then sent out over the network. The value of the response (out_data) to the query from SPP is also compressed by TP1/Server and then sent over the network. TP1/Client/J receives the response, restores the compressed data, and then passes it to the CUP.

The following figure provides an overview of the data compression facility.

Figure 2-37 Overview of database adapter

This facility is applicable when the version of TP1/Server at the service request destination is 03-03 or later.^# It supports the RPC communication mode and all RPC interfaces. However, the following differences apply, depending on the TP1/Server version at the service request destination:

• For a TP1/Server version earlier than 03-06
  If the input parameter value is not compressed, the response value is not compressed by TP1/Server even if compression would be effective.
  
• For a TP1/Server version 03-06 or later
  The response value is compressed by TP1/Server if compression would be effective, even if the input parameter value was not compressed.
  

#

For an RPC using the remote API facility, the data compression facility is supported if the TP1/Server version is 03-05 or later.

The data compression facility cannot be used if the XA transaction linkage facility is used from uCosminexus TP1 Connector or Cosminexus TP1 Connector and if the TP1/Server version is 07-00 or earlier.

Organization of this section

2.12.1 Effects of the data compression facility

2.12.2 Notes about using the data compression facility