Kevin Grittner wrote:
> Robert Haas <robertmhaas@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 <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
