DSQSBSTG (adjusting GETVIS storage used for report data)

Parameter name

DSQSBSTG

Short form

B

Valid values

From 0 to 99,999,999 bytes

Default

500,000 bytes

In VSE, to produce reports and temporarily store data, QMF uses GETVIS storage, which is virtual storage within the CICS partition. VSE/ESA 1.3 limits GETVIS storage according to the partition size you define for CICS. To ensure each user has enough storage for QMF queries and reports, first adjust the CICS partition size according to the number of QMF users and the size and complexity of reports they are creating.

After you size the CICS partition, use the DSQSBSTG parameter to specify the maximum amount of GETVIS storage QMF uses to run queries and produce reports. Specify the storage amount in bytes. The user can specify the GETVIS storage from a cleared CICS screen.

For example, the following command starts QMF from a cleared CICS screen and specifies that a maximum of 0.8 MB of GETVIS storage can be used to store the user's report data:

QMFn B=800000

Choosing the right amount of GETVIS storage for each user

QMF needs a minimum amount of GETVIS storage to display a report in the default format. This minimum is between 15,000 and 31,000 bytes (15 to 31 KB) depending on how the storage in your CICS partition is distributed. Set DSQSBSTG to 0 when you want QMF to use the minimum value for GETVIS storage.

The default value of 0.5 MB can accommodate most QMF transactions. However, the amount of virtual storage needed varies for individuals using a report format other than the default. Users working with very large reports may need up to 1 MB or more of virtual storage. See the QMF Referencefor information on report formatting options.

Important: QMF requires a minimum of 15 MB GETVIS storage for up to 20 users (24 MB total virtual storage for the partition). When you increase a user's GETVIS storage using the DSQSBSTG parameter or when you add more QMF users, make sure you increase the value of the CICS ALLOC parameter so that each user has enough GETVIS storage to run queries and produce reports. A QMF transaction could time out waiting for storage to become available.

Performance tradeoffs

Use the DSQSPILL parameter to provide users with a spill file; if the spill file is full, QMF continues to retrieve data into GETVIS storage in amounts specified by the DSQSBSTG parameter. If you use too low a value for DSQSBSTG, performance will be poor even if you use a spill file, because QMF must return to the database several times to retrieve the requested data. Consider using a governor exit routine to limit rows retrieved from the database so that less GETVIS storage is used for queries and reports.