CA Datacom/DB DBUTLTY Configuration › Overriding DBUTLTY DBMSTLST Buffer Specifications at Execution Time

Overriding DBUTLTY DBMSTLST Buffer Specifications at Execution Time

As discussed in the previous section, the default DBUTLTY DBMSTLST module does not specify enough buffers for large DBUTLTY executions. The previous section provided recommendations for changes to the DBMSTLST settings to provide a more substantial set of buffers.

However, this approach lacks some flexibility for certain utility operations where more buffers could aid in speeding up the processing. For example, during a DBUTLTY RECOVERY=FORWARD operation having a much larger number of IXX, DXX, and data buffers could significantly improve the recovery time and shorten the time it takes to rebuild a database after a failure. However, for other utilities such as a normal backup or extract, these additional buffers may not be beneficial.

For these special cases, the DBUTLTY SET command can be used to override the buffer settings for a given DBUTLTY execution. Once the SET command has been issued, the selected buffer allocation remains in effect until the DBUTLTY execution ends or another SET command is encountered.

Business Value

Using the SET command can allow you to experiment with the number of buffers needed to support long-running DBUTLTY jobs. In some cases, the ability to add additional buffers to speed recovery or other processing can be critical to sites that have experienced a database outage.

Additional Considerations

The DBUTLTY SET function uses a freeform text processor to pass various commands and settings from the JCL stream to the DBUTLTY program. Providing buffer specifications is just one of the overrides that this function can provide to the DBUTLTY program, as shown in the following example:

SET OPTION1=’DATANO=9999;DXXNO=9999;IXXNO=999’

The SET function shows you how to override data buffers to 9999, DXX buffers to 9999 and IXX buffers to 999.

Do not to set the buffers numbers so high that the DBUTLTY 31-bit memory size exceeds the size of the region’s available 31-bit memory. For DBUTLTY functions that also include a sort, some planning must be done to help ensure ample room for the sort’s 31-bit memory requirements.