I'm scoping a project to display the choices and plans the
planner/optimizer considers while PostgreSQL develops a plan. It would
be primarily a teaching tool but may be of use to users curious about
the inner workings of the planner.
This is in contrast with EXPLAIN, which provides information about the
*final* plan selected by the planner. This tool would show details
about the access methods available at each step and the associated
access costs, for example.
There is a TODO item: "Allow EXPLAIN output to be more easily processed
by scripts, perhaps XML" which could be a good first step for this
project.
Is anyone working on a related project?
-Tom Raney
