File Manager Delta Compares

Users have an issue with the File Manager Compare design going back to 2007 (or maybe earlier).

Let's say you are comparing a file with hundreds of thousands of records. Each record has hundreds of fields. And within all those records we have:

• A couple of inserted records
• A couple of deleted records
• Thousands of changed records, but only a few fields are changed in each one.

We want to suppress display of all of the matching information. There is no desire to page through a million lines of output just to get to the good stuff.

This is impossible to do in File Manager!

The output is controlled by three options: Listing Type, Long Report Exclusions, and Show Changed Fields Only.

The natural choice is to do a Delta compare (which is the same as a Long report excluding Matched records), with Show Changed Fields Only.

It is because File Manager does not process “Show Changed Fields Only” to mean suppress matched fields. It means to only show changed fields on changed records. In other words, if the files are different due to inserts and deletes it does not display any data for those differences.

If you turn off the Show Changed Fields Only, then you do get the fields on inserts and deletes, but you also get all of the fields displayed on changed records.

My argument is this makes no makes no sense – it defies reason that anyone would want it to work this way.

What we need is for the normal processing of File Manager compares to make sense. When you tell it you want a delta compare with only showing delta fields, it should show exactly what the differences are between the two files, and nothing else.

If there is a requirement to be able to suppress even more data (such as suppressing display of fields on inserts and deletes, but not changes), then that should be addressed separately, in a non-default way. For example, consider how the Long report format has an additional option that allows fine tuning of its output records – you can chose Long, but suppressing matches, inserts, deletes or changes.

The way Show Changed Fields Only works now is as if some customer didn't want to see Inserts and Deletes on a Long report, so File Manager changed Delta reports to suppress Inserts and Deletes.

If IBM's answer is that we can accomplish our requirement by have File Manager create files of the deleted and inserted records, I don't agree: that would lose the context of those changes within the original files, and it is a kludge to work around a design deficiency.

The bottom line is that because of this problem, File Manager File Comparison is hamstrung just when it is needed the most: comparing large files (such as production parallels) and finding the where the differences are. It is impossible to see all the differences without also displaying so many lines of matched data that it renders it useless.