Db2 Connect performance troubleshooting

If Db2 Connect users are experiencing long response times during large queries from IBM mainframe servers, there are some configuration settings that can help you troubleshoot the performance problem.

The following areas should be examined for the possible cause of the performance problem:
  1. For queries which result in returning large data blocks from the IBM mainframe server (usually 32K of data and above), ensure that the database manager configuration parameter RQRIOBLK is set to 32767. This can be done using the Command Line Processor (CLP) as follows: 
       db2 update database manager configuration using RQRIOBLK 32767
  2. Ensure the maximum RU size defined in the IBMRDB mode definition is set to a suitable value. It is recommended that the size is not less than 4K for connections using Token-ring hardware. For connections using Ethernet hardware, note the maximum Ethernet frame size of 1536 bytes, which might be a limiting factor.