Re: Planning time in explain/explain analyze

Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Jan 9, 2014 at 11:45 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Uh, no, wasn't my suggestion.  Doesn't that design imply measuring *every*
>> planning cycle, explain or no?  I was thinking more of just putting the
>> timing calls into explain.c.

> Currently the patch includes changes to prepare.c which is what seems
> odd to me.  I think it'd be fine to say, hey, I can't give you the
> planning time in this EXPLAIN ANALYZE because I just used a cached
> plan and did not re-plan.  But saying, hey, the planning time is
> $TINYVALUE, when what we really mean is that looking up the
> previously-cached plan took only that long, seems actively misleading
> to me.

Meh.  Why?  This would only come into play for EXPLAIN EXECUTE stmtname.
I don't think users would be surprised to see a report of minimal planning
time for that.  In fact, it might be a good thing, as it would make it
easier to tell the difference between whether you were seeing a generic
plan or a custom plan for the prepared statement.
        regards, tom lane