I'm wondering about how big I can make a hash before it ceases to be effective; are there any tips or guides on this point? Obviously, the answer may be machine-specific with regards to physical resources, but further help may be useful. In my application, my simple hash of scalars (for duplicate detection) hits a size of over 55 million, at which point my system seems to be dying of asphyxiation. Are there any heuristic watermarks about when a hash may stop being effective in Perl?