Kevin Grittner wrote: > Robert Haas <robertmh...@gmail.com> wrote: > > > I sometimes want to know what the planner thinks the cost of some > > plan other than the one actually selected would be. > > Another DBMS I used for years had a way to turn on an *extremely* > verbose mode for their planner; it showed everything it considered > with its related cost information. Even a moderately complex query > generated hundreds or thousands of lines of output, so I rarely used > it; but for those particularly stubborn queries, where you just can't > understand why it's picking the plan it is, a little work wading > through the output would *always* clear up the mystery. > > Now that we can generate EXPLAIN output in more structured formats, > perhaps we could think about adding an "extremely verbose" mode where > the planner would "think out loud" as a whole separate section from > where we show the chosen plan?
Well, we have OPTIMIZER_DEBUG, which is a compile-time flag, but that perhaps can be changed to output as part of EXPLAIN. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
