Delta logic and merging

[arvind]

Hi All,
I have two source files which will be merged and loaded into the target output file.
Need to implement the delta logic on these two files.

There are some 50 columns in the source 1 and 30 in source 2.
We are using 30 columns from source 1 and 5 columns from source 2 for merging.

Which is the best practice?
1) Implement delta logic first then merge.
2) Merge first and implement delta logic.

Delta logic: compare with prior day file, if record are new or changed the load in output file.

Thanks in advance
Arvind

[bcarlson]

My personal preference would be to do delta processing first - keep it unique between input files since the delta processing for file 1 doesn't have anything to do with the delta processing for file 2.

The delta processing should be able to run concurrently. Then merge the outputs and continue processing - you'll have smaller volumes to process at this point, too.