grep a large list against a large file

Question

I am currently trying to grep a large list of ids (~5000) against an even larger csv file (3.000.000 lines).

I want all the csv lines, that contain an i

Answer 1

You may get a significant search speedup with ugrep to match the strings in the_ids.txt in your large huge.csv file:

ugrep -F -f the_ids.txt huge.csv

This works with GNU grep too, but I expect ugrep to run several times faster.