Re: Planning time in explain/explain analyze

On Thu, Jan 9, 2014 at 11:45 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Greg Stark <stark@mit.edu> writes:
>> On Thu, Jan 9, 2014 at 9:14 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> In short then, I think we should just add this to EXPLAIN and be done.
>>> -1 for sticking the info into PlannedStmt or anything like that.
>
>> I'm confused. I thought I was arguing to support your suggestion that
>> the initial planning store the time in the cached plan and explain
>> should output the time the original planning took.
>
> 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.

-- 
Robert Haas
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