Fast/Unload: Difference between revisions
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The ''Fast/Unload User Language Interface'', purchased as a separate Fast/Unload option, | The ''Fast/Unload User Language Interface'', purchased as a separate Fast/Unload option, | ||
allows one to invoke Fast/Unload using the FastUnload or [[FastUnloadTask method]] of | allows one to invoke Fast/Unload using the FastUnload or [[FastUnloadTask method]] of | ||
the [[ | the [[Recordset class]] or the [[$FunLoad]] function in a User Language program. With this | ||
approach, an application builds a set of records to be unloaded, using standard User | 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 | Language statements; for example, you can reduce unload time by restricting the set of | ||
Revision as of 18:02, 21 June 2011
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 User Language 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, 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. The Fast/Unload User Language 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 the $FunLoad function in a User Language 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. The Fast/Unload User Language Interface also provides the ability to unload data from a Model 204 group.
With the Fast/Unload User Language Interface, the processing can be performed either synchronously or asynchronously.
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.
See List of Fast/Unload $functions or the FastUnloadTask class for more information.