VSAM Performance Enhancement › VPE Operation › VPE Rules Table › RULE Statement

RULE Statement

The following section explains the RULE statement.

RULE	(Scope of the rule)

[INCLUDE|XCLUDE]
 [,JOB=cccccccc|STEP=cccccccc|DDNAME=cccccccc|DSN=cccccccc]
 (Job/Step specified parameters)
 [,POOL=n]
 [,TGTBUF=nnM]
 [,MINBUF=nnM]
 [,ABENDNOMIN=NO|YES]
 [,MINRESV=nnnK]
 (DDNAME/DSN specific parameters)
 [,POWERFACT=nn]
 [,SIS=NO|YES]
 [,DFW=NO|YES]
 [,FORCEMODE=SEQ|LSR]
 [,BUFND=nn]
 [,BUFNI=nn]
 [,BUFSP=nn]
 [,VSAMREC=NO|YES]

The RULE statement specifies VPE processing options for jobs, steps, and data sets. The values specified on a RULE statement overrides the corresponding values specified in the SYSOPT and VSAM statements.

INCLUDE|XCLUDE

Specifies whether this RULE statement is including jobs, jobsteps, or data sets, or excluding them.

JOB=cccccccc|STEP=cccccccc|DDNAME=cccccccc| DSNAME=cccccccc

Specifies the job name, step name, DDNAME, or DSNAME of the job, step, or data set being included in or excluded from VPE processing using this RULE statement. The values specified can contain one or more asterisks, which represent wild card indicators. Note that for data set names wild card characters are not node-specific. For example: "A*T" matches DSN=ABCTEST and DSN=ABC.NODE.TEST.

Note: A node is one portion of the data set name delimited by a period. The nodes of ABC.NODE.TEST are ABC, NODE, and TEST.

JOB/STEP Specific Parameters

These parameters are valid only when the RULE statement specifies JOB= or STEP=.

POOL=n

Specifies the LSR pool number which VPE is to use for I/O buffers for the job(s), step(s), or data set(s) affected by this RULE statement. The default value is 3.

This is the pool number and not the number of pools. VSAM supports 16 LSR pools for data components and 16 for index components. Both sets of pools are numbered 0 through 15. POOL= specifies which of these pairs of pools is to be used. This value need not match the value specified on the POOL parameter of the VSAM statement.

TGTBUF=nnM

Directs VPE to attempt to obtain the specified number of megabytes for the VSAM I/O buffer for the job(s), step(s), or data set(s) affected by this RULE statement. If VPE cannot obtain this much space, it reduces the request until the space request succeeds, or until the minimum buffer size is reached (see the MINBUF=nnM parameter below). The default target buffer size is 4 Mb.

Note: This parameter overrides the TGTBUF parameter on the VSAM statement.

MINBUF=nnM

Works in conjunction with the ABENDNOMIN=YES parameter. MINBUF=nnM specifies the minimum VSAM I/O buffer size which is acceptable for the job(s), step(s), or data set(s) affected by this RULE statement. The default is zero. If a nonzero value is specified for MINBUF=nnM and ABENDNOMIN=YES is specified, VPE abends the job step if the minimum buffer space cannot be obtained.

ABENDNOMIN=NO|YES

ABENDNOMIN=YES directs VPE to abend the jobstep when the minimum buffer space specified by MINBUF= cannot be obtained. Use this parameter whenever it is unacceptable for a jobstep to run without buffering.

MINRESV=nnnnK

Specifies the minimum amount of memory to reserve below the 16 Mb line for the application to use for the job(s), step(s), or data set(s) affected by this RULE statement. The default setting is 300K. VPE does not enhance sequential file buffering if this amount of memory is not available. When LSR buffers are being acquired below the 16 Mb line, this value reduces the size of the VSAM I/O buffers if this amount of space is not available.

VPE Tuning Tip: If you find that TGTBUF= (or even MINBUF=) requirements cannot be met, reduce MINRESV=.