Fast/Unload overview: Difference between revisions

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==Fast/Unload topics==
==Fast/Unload topics==
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<li>[[Fast/Unload invocation]]
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Revision as of 19:51, 9 February 2015

Fast/Unload is a utility whose primary function is to quickly unload data from a Model 204 data file to one or more sequential data sets. The Fast/Unload utility consists of several functional units:

  • One unit is a data extraction facility which reads data from a Model 204 data file.
  • Another unit is a compiler which converts a special data language describing the output format to machine language. The generated machine language actually performs the output function.
  • A third unit is a reporting facility which provides a job log and reports any special conditions or errors that might have occurred during a run.

Fast/Unload can either be invoked directly as a standalone load module or from a SOUL program. When invoked as a standalone load module, Fast/Unload enqueues the data file in share mode unless explicitly requested otherwise. If the enqueue fails, the Fast/Unload terminates with an error condition code. It is thus the file manager's job to ensure that when Fast/Unload is run as a standalone load module, Model 204 does not have the file to be unloaded locked in exclusive mode.

Fast/Unload SOUL Interface

The Fast/Unload SOUL Interface, purchased as a separate Fast/Unload option, allows one to invoke Fast/Unload using the FastUnload or FastUnloadTask method of the Recordset class, or using the $Funload function in a SOUL program.

With this approach, an application builds a set of records to be unloaded, using standard User Language statements; for example, you can reduce unload time by restricting the set of records using indexed Model 204 fields. The Fast/Unload load module runs in a subtask (or PST under CMS) of Model 204. Since the unload is from a Model 204 record set, the Fast/Unload SOUL Interface automatically provides the ability to unload data from a Model 204 group; standalone Fast/Unload provides that functionality by allowing multiple Model 204 file names on the OPEN statement.

The Fast/Unload SOUL Interface processing can be synchronous or asynchronous.

A system manager can cancel or examine Fast/Unload requests, and each user can perform the same functions on asynchronous requests that he or she initiated.

Fast/Unload topics