Packing multiple statement requests improves network/mainframe efficiency by reducing the number of sends and receives between the application and the database.
To determine the ideal pack factor to specify in the Pack attribute, first use the PackMaximum attribute by setting it to 'Yes'. Setting this attribute to Yes on the first job run sets up iterative interactions with the database to heuristically determine the maximum possible pack factor. At the end of the run, this value is displayed in the Stream operator’s logged output. Specify that determined value in the Pack attribute on subsequent runs. Set the PackMaximum to 'No'.
Alternatively, the Stream Driver TD_Evt_PackFactor event returns the current pack factor when queried. This value is available after a connection is initiated and before it is terminated.
- The schema has variable-length columns and
- Array Support is on and
- One of the following:
- The PACK factor is set to 2400
- The PACKMAXIMUM is set to 'Y[es]'
- Neither the PACK factor attribute nor PACKMAXIMUM attribute is populated
The user will be informed the "floating" Pack factor via a new informational message similar to the following:
**** 14:50:34 The PACK factor has changed. The minimum PACK factor is about 1270 data records per request. The maximum PACK factor is about 1298 data records per request.
In the message, the word "about" indicates that worker instances can have a different Pack factor.