Re^2: with tied hash, 'each' gives key that doesn't 'exists'

[locked_user sundialsvc4]

FYI, keys would be very inappropriate in this case, because it would read the file twice ... build a complete list of the record keys in RAM (virtual memory) ... then retrieve the records by those keys.   Most of the time you would run out of RAM.   But even if you didn’t, you’d be doing a rather massively too-much amount of unnecessary work.

each, on the other hand, simply walks through the file.   There is no memory-footprint to speak of.   Furthermore, it always does so in ascending order by key.   Very often, that is exactly what you want.   (What bearing if any this may have on this issue, I don’t know.)

[cmac]

It is not generally true that each returns keys (or key/value pairs) in ascending order by key. It is true for some base classes that one can tie a hash to, but not for DB_File which is what the OP is asking about. See the description of each in Programing Perl 3rd Edition p. 703.