Local request queue data set

The local request queue data set stores pending BTS requests; for example, timer requests or requests to run activities. It is recoverable and is used to ensure that, if CICS® fails, no pending requests are lost.

Requests that CICS can run immediately, for example, requests to run activities, are stored on the data set only briefly. Requests that CICS cannot run immediately, for example, timer or unserviceable requests, might be stored for longer periods. When CICS has processed a request, the request is deleted from the data set.

The local request queue data set differs from repository data sets in the following ways:
  • It is a mandatory CICS data set. You must define one, even if you do not use BTS.
    Note: Procedure DFHDEFDS in library SDFHINST contains a definition of the LRQ. For information about how to use DFHDEFDS, see DFHDEFDS job for CICS region data sets.
  • You must define one, and only one, to each CICS region.
  • It is never shared. The local request queue data set relates solely to requests generated on the local region.

Specify the following parameters to IDCAMS:

INDEXED
BTS local request queue data sets must be in KSDS format.
KEYS(40 0)
The file key. The file key is 40 bytes in length and is located at offset X'0' in the record.
LOG(UNDO|ALL)
The recovery options for the data set:
UNDO
The data set is recoverable.
ALL
Forward recovery is required. If you specify LOG(ALL), you must also specify a log stream on the LOGSTREAMID parameter.
LOGSTREAMID(log_stream_ID)
The identifier of the log stream to which forward recovery records are to be written. This parameter is required only if you specify LOG(ALL).
RECORDSIZE(average  maximum)
The average and maximum size of records on the data set, in bytes.

Specify average as 2232 bytes and maximum as 2400 bytes.

Figure 1 shows example JCL for defining a BTS local request queue data set.
Figure 1. Example JCL for defining a BTS local request queue data set. The numbers are for illustration only.
//SMITHGOT JOB (WINVMC,SMITH),CLASS=E,USER=username
//IJMRLRQ  EXEC PGM=IDCAMS,REGION=6144K
//SYSPRINT DD SYSOUT=A
//AMSDUMP  DD SYSOUT=A
//SYSIN    DD *
  DEFINE CLUSTER (                         -
                NAME( CICSTS54.CICS.LRQ )  -
                LOG(UNDO)                  -
                CYL(2,1)                   -
                VOLUME (SYSDAV)            -
                KEYS( 40 0 )               -
                INDEXED                    -
                RECORDSIZE( 2232 2400 )    -
                FREESPACE( 0 10 )          -
                SHAREOPTIONS( 2 3 )        -
                )                          -
  DATA          (                          -
                NAME( CICSTS54.CICS.LRQ.DATA )    -
                CISZ(2560) -
                ) -
  INDEX         ( -
                NAME( CICSTS54.CICS.LRQ.INDEX )   -
                )                          -
/*
//

The LRQ data set is critical to the operation of BTS. Because its loss could severely impact the progression of BTS activities, you should consider defining it to use backup while open (BWO) and forward recovery.