It would be ood if you can suggest something other than loading the file content into database and fetching it.

Probably, but not based on the information you've provided so far. Why do you seem reluctant to provide information?

Please provide:

• The size in bytes of both files.
• The number of records in both files.
• The number of fields in the lines of both files.
• A couple of sample records from both files.

  If the data is proprietary, then take a couple of sample records and change the identifying words, numbers etc., but try to ensure that they remain realistic.

• And idea of how often you will need to do this and how often the file(s) change.

  Ie. "The bigger file remains constant and the smaller changes one a week";

  Or: "This is a one-off problem never to be repeated".

  Or: "The two files never change, but the (combination of) fields used for comparison changes every day".

  Or: ...

With that information, we here have a realistic chance of understanding the scale of the problem and possible solutions.