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Determining whether queries can benefit from acceleration

To evaluate the potential savings for both accumulated elapsed time and processor time, you can enable the modeling of query workloads for plans that run on an accelerator server.

About this task

Results are recorded in the accelerator fields of accounting trace IFCID 003. Only queries that DB2® deems eligible to run on an accelerator server are included in IFCID 003.

Procedure

To determine whether queries can benefit from acceleration:

Start of changeEnable the modeling of query workloads for plans that run on an accelerator server by setting the following subsystem parameters and special registers:
  • Set the ACCEL_MODEL subsystem parameter to YES
  • Set the QUERY ACCELRATION subsystem parameter value to NONE, ENABLE, ENABLE WITH FAILBACK or ELIGIBLE.
  • Set the CURRENT GET_ACCEL_ARCHIVE subsystem parameter to NO.
  • Set the CURRENT GET_ACCEL_ARCHIVE special register to NO

If other values are specified, DB2 tries to accelerate queries instead of doing accelerator modeling.

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