Fast/Unload: Difference between revisions
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<var class="product">Fast/Unload</var> is a utility whose primary function is to quickly unload data from a | |||
Model 204 data file to one or more sequential data sets. | 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 | The <var class="product">Fast/Unload</var> utility consists of several functional units. One unit is a data extraction facility which reads data from a <var class="product">Model 204</var> 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 | 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 | job log and reports any special conditions or errors that might have occurred during a | ||
run. | run. | ||
<var class="product">Fast/Unload</var> can either be invoked directly as a standalone load module or from a User | |||
Language program. When invoked as a standalone load module, | Language program. When invoked as a standalone load module, <var class="product">Fast/Unload</var> | ||
enqueues the data file in share mode unless explicitly requested otherwise. If the | enqueues the data file in share mode unless explicitly requested otherwise. If the | ||
enqueue fails, | enqueue fails, <var class="product">Fast/Unload</var> terminates with an error condition code. It is thus the file | ||
manager's job to ensure that when | manager's job to ensure that when <var class="product">Fast/Unload</var> is run as a standalone load module, | ||
<var class="product">Model 204</var> does not have the file to be unloaded locked in exclusive mode. | |||
The | |||
allows one to invoke Fast/Unload using the FastUnload or [[FastUnloadTask | The <var class="product">Fast/Unload User Language Interface</var>, purchased as a separate <var class="product">Fast/Unload</var> option, | ||
the [[Recordset class]] or the [[$FunLoad]] function | allows one to invoke <var class="product">Fast/Unload</var> from User Language, | ||
approach, an application builds a set of records to be unloaded, using standard User | using the <var>[[FastUnload (Recordset function)|FastUnload]]</var> or <var>[[FastUnloadTask (Recordset function)|FastUnloadTask]]</var> functions of | ||
the <var>[[Recordset class|Recordset]]</var> class or the [[$FunLoad]] function . | |||
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 | 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 | records using indexed <var class="product">Model 204</var> fields. The <var class="product">Fast/Unload</var> load module runs in a subtask | ||
(or PST under CMS) of Model 204 | (or PST under CMS) of <var class="product">Model 204</var>. | ||
With the <var class="product">Fast/Unload User Language Interface</var>, the processing can be performed either | |||
With the Fast/Unload User Language Interface, the processing can be performed either | |||
synchronously or asynchronously. | synchronously or asynchronously. | ||
A system manager can cancel or examine <var class="product">Fast/Unload</var> requests, and each user can | |||
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. | perform the same functions on asynchronous requests that he or she initiated. | ||
To explore the details, see "[[:Category:Fast/Unload User Language Interface|Components]] of the <var class="product">Fast/Unload User Language Interface</var>". | |||
The <var class="product">Fast/Unload User Language Interface</var> also | |||
provides the ability to unload data from a Model 204 group. | |||
The standalone <var class="product">Fast/Unload</var> load module | |||
can also unload a group of files, although without access to group definitions in <var class="product">Model 204</var>. | |||
Revision as of 01:33, 23 June 2012
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 from User Language, using the FastUnload or FastUnloadTask functions of the Recordset class or the $FunLoad function . 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. 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. To explore the details, see "Components of the Fast/Unload User Language Interface".
The Fast/Unload User Language Interface also provides the ability to unload data from a Model 204 group. The standalone Fast/Unload load module can also unload a group of files, although without access to group definitions in Model 204.