Today's COBOL Performance Tuning tip is another that can be applied to any language. You may think it is so obvious that it is not a tip, but common sense. The only reason I am even giving it a blog entry is because I have seen this happen.
I am positive a request came from a Business Analyst or the customer to not write any extract records for customers with a certain field containing a specific value. The programmer found the program creating the extract records, found where the call was to write the extract records, and just before that call they inserted an IF statement to go to the paragraph exit if that certain field contained the specific value.
So after the record was read in with the certain field with the specific value, the programmer allowed several more files, tables, history records, etc. to be read in, calculations to occur, calls to be executed and the extract to be completely built before bypassing the customer.