WAIT FOR DATA field (QUERY_ACCEL_WAITFORDATA subsystem parameter)
The QUERY_ACCEL_WAITFORDATA subsystem parameter determines the default value that is to be used for the CURRENT QUERY ACCELERATION WAITFORDATA special register.
The QUERY_ACCEL_WAITFORDATA subsystem parameter is used when no value is explicitly set for the CURRENT QUERY ACCELERATION WAITFORDATA special register by the SQL statement SET CURRENT QUERY ACCELERATION WAITFORDATA.
| Acceptable values: | 0.0–3600.0 or 0–3600 |
|---|---|
| Default: | 0.0 |
| Update: | option 31 on panel DSNTIPB |
| DSNZPxxx: | DSN6SPRM.QUERY_ACCELERATION_WAITFORDATA |
Valid values are a DECIMAL(5,1) numeric constant in the range of 0.0–3600.0 seconds. For example, a value of 20.0 represents 20.0 seconds (or 20000 milliseconds), and a value of 30.5 represents 30.5 seconds (or 30500 milliseconds). The maximum value of 3600.0 means that the query is delayed for 60 minutes.
The default value is 0.0, which means that the query is not delayed and is run immediately on the accelerator. Other WAITFORDATA behavior is not applied to the query.
The wait time value can also be specified as an INTEGER numeric constant value ranging from 0–3600 seconds, which Db2 will convert to a DECIMAL (5,1) value.
When a non-zero value is specified for QUERY_ACCEL_WAITFORDATA, Db2 and the accelerator will apply other WAITFORDATA delay behavior, restrictions, and requirements to all dynamic queries to be accelerated. These behaviors, restrictions, and requirements can validly stop or even fail the acceleration of some queries that formerly were accelerated successfully. If you specify a non-zero WAITFORDATA delay on the new Db2 subsystem parameter, all dynamic queries on the Db2 subsystem for which acceleration is requested will be affected. For more information about these behaviors, restrictions, and requirements, see SET CURRENT QUERY ACCELERATION WAITFORDATA statement.