OK..let me get this straight. You're querying a database to get all usernames so you can use Perl to see if a given username is present?

If that's the case -- and this isn't a rather odd homework assignment -- make the database do the work and write the query to see if the username is present. This way Perl would get a true/false answer from the database, and you wouldn't have to check 8,000,000 usernames

In Perl, one way to do it would be to load all the usernames into an array and use grep

$yes = grep { /$username/ } @usernames;
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