Re: optimizing common subqueries

As I understand it, Postgres's query planner considers only trees of
joins - I don't know what the technical implications are of using DAG
plans, other than the obvious blowup in planning space.

I was recently in a similar situation, where a script essentially
needed to do a self-join on the result of a complex query.  The script
uses a temp table to store the results of the first query, and then
does a second query using the temp table - effectively, I have done
common-subexpression reduction by hand.  This repeated fragment of your
example:

      SELECT * FROM common_pmids('mycn','trka')

might be a candidate for such treatment.

- John Burger
   MITRE