You are abusing this forum.

How do you come to that conclusion? You ask a vague question and post no code or data as background and, it would seem, you are dissatisfied with the necessarily vague pointers you got in reply. You then re-post exactly the same question some hours later, again with no code or example data, but with the added information that the run took 7 hours and that you might have taken salva's advice to use index. LanX is quite right, you should have kept in the original thread. As for abusing the forum, I would suggest that the boot is on the other foot!

I come here to discuss interesting perl related issue.

How about posting some interesting Perl code so that we have something to go on?

Update: Fixed typo.