title: Where can I find a description of plan nodes?
body: <p>I'm working my way through a postgres query plan for the first time.</p>
  
  <p>I'm having some trouble because I don't seem to be able to find any documentation that describes what each of the plan nodes are.  In many cases, the name provides me with a reasonable guess, but in several the name of the plan node is too generic for me to have confidence in it.</p>
  
  <p>Where can I find a list of types of plan nodes, with descriptions of each?</p>