title: Performant Haskell hashed structure.
body: <p>I am writing program that does <em>alot</em> of table lookups. As such, I was perusing the Haskell documentation when I stumbled upon <code>Data.Map</code> (of course), but also <code>Data.HashMap</code> and <code>Data.Hashtable</code>. I am no expert on hashing algorithms and after inspecting the packages they all seem really similar. As such I was wondering:</p>
  
  <p>1: what are the major differences, if any?</p>
  
  <p>2: Which would be the most performant with a high volume of lookups on maps/tables of ~4000 key-value pairs?</p>