PLP/MCU Tasks §

Because there is the potential for a great many files to be created, the Results and Work folders (introduced in the previous page) are further subdivided according to the five main tasks that might be performed on a file in PLP/MCU: 

  1. Pre-processing 
  2. Self-PLP 
  3. MCU review of Self-PLP results 
  4. PLP 
  5. MCU review of PLP results 

In the typical scenario, only two, or perhaps three of these tasks will be performed. But because of the comprehensive nature of the PLP/MCU process, it is necessary that they all be supported, and maintained as separate processes. Hopefully the following discussions will illuminate this need. 

The folder structure preserves the logical order above by using a numerically-prefixed name, as follows: 


1-pp: Pre-Processing 

There are two purposes of pre-processing. The first is to clean-up and normalize all of the match key fields that will be used by PLP to query the database. This allows PLP to concentrate on what it needs to do: search databases and match records. If you are a TMQ customer for Osmosis, then you will normally skip this step, as this pre-processing performs the same work as is described in a 'Global Fix report'. 

The second purpose, closely related to the first, is to normalize, and even compose if necessary, the unique system Id of the source/library file being processed, and of any holding or items that might be loaded via that file. The parameters for this second bit of processing are described in detail in the PLP section called Library Load Profiles 

2-splp: Self-PLP 

Before searching the database for matching records, we first want to make sure there are no dupes within the source file itself. 'Self-PLP' is the way we do this. 

Self-PLP uses the same match rules as PLP, but instead of searching a system database, it searches a file of MARC records. Self-PLP makes one pass on the source file to create an internal database of all of the match keys that are present in the file1). It then makes a second pass through the file, and more or less pretends to run as if it were PLP itself. 

If there are duplicates in the source file to be loaded, Self-PLP will merge them together: the unique system Id of one record, and all of the holdings, will be added to the other record (the choice as to which record is the mergee is determined via the Preferences defined for the match rules). If there are matching records that fail crosschecks, they will be output to a 'XCFail' file and should be resolved in MCU (step 3) before the file is sent on to PLP (step 4). 

Again, if you are a TMQ Osmosis customer you will normally skip this step, as Osmosis runs a version of Self-PLP on every file that it processes (the results will be found in your Duplicate Rercord Logs). 

3-mcu-splp: MCU Review of Self-PLP results 

If Self-PLP identifies any duplicate records in the source file that fail to pass crosschecks, the next step will be to review those records in MCU. Once the problems are resolved, the resulting file can then be sent on to the next step, which is PLP. 

If you are a TMQ Osmosis customer, MCU may be able to assist you with the clean-up of duplicate records in your system. The 'Possible matches' identified by Osmosis are MCU-able files, and you can use the display capabilities of MCU to help you quickly resolve duplicates on your system 2) 

4-plp: PLP 

PLP searches each record in the source file in your library database and looks for matches according to the match rules in place. (This processi s described in more detail here). 

5-mcu-plp: MCU Review of PLP results 

If PLP identifies any records in the source file that match database records but fail to pass crosschecks, the next step will be to review those records in MCU. Once the problems are resolved, the resulting file can then be loaded to the library system. 

Next: MCU--Basic display setup 

1) if you are interested in this sort of thing, have a look at the file named like 'Splp-00000000-kbm.txt' in the '../Work/2-splp/' folder, after Self-PLP is finished
2) for example, run MCU to identify the dupes in one window, and have a connection to your system in another window
mcu/plp-mcu_tasks.txt · Last modified: 2013/04/27 09:09 (external edit)
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