Where's that doc on plans ?

Jean-Christophe Boggio <cat@thefreecat.org> writes:

A few days ago I read a very interesting doc about postgres' query
planner, how to read an EXPLAIN plan, how is a cost calculated, etc.
but I can't find it anymore.

If you're not thinking of the EXPLAIN tutorial in

http://www.postgresql.org/devel-corner/docs/postgres/performance-tips.html

then I'd be interested to know what you *are* thinking of...

regards, tom lane