I see that file 1 is humongous (6 GB). How big is file 2? I guess output 1 is "extract records from file 1 that match an id in file2?". I am unclear as to the algorithm for output 2.

Have you tried any code yet? If so post it and your thoughts on algorithms.

Update: The size of file 2 matters in terms of whether this can be kept in memory or not. If so, this output 1 is relatively easy. If not, then some pre-sorting or a DB approach would be necessary.

In reply to Re^3: Query large tab delimited file by a list by Marshall
in thread Query large tab delimited file by a list by Elninh05

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