Controlling deadlock detection

Use the DEADLOCK parameter in the IRLM startup procedure to control how often IRLM does its deadlock detection processing.

Specify the parameter as follows:

DEADLOCK='x,y'

x: The number of seconds between two successive scans for a local deadlock (DEADLOCK TIME value on installation panel DSNTIPJ). The default is 1 second. Values can range 1–5 seconds, or 100 to 5000 milliseconds.
y: The number of local scans that occur before a scan for global deadlock starts (DEADLOCK CYCLE value on installation panel DSNTIPJ). IRLM always uses a value of 1.

Global deadlock detection requires the participation of all IRLM members in the data sharing group. Each IRLM member has detailed information about the locks that are held and are being waited for by the transactions on its associated Db2 member. However, to provide global detection and timeout services, each IRLM is informed of all requests that are waiting globally so that the IRLM can provide information about its own blockers. That IRLM also provides information about its own waiters. The IRLM members use XCF messages to exchange information so that each member has this global information.