Re: [HACKERS] Runtime Partition Pruning

On 2 December 2017 at 08:04, Robert Haas <robertmhaas@gmail.com> wrote:
> On Fri, Dec 1, 2017 at 6:20 AM, Beena Emerson <memissemerson@gmail.com> wrote:
>> David Q1:
>> postgres=#  explain analyse execute ab_q1 (3,3); --const
>>                                                QUERY PLAN
>> ---------------------------------------------------------------------------------------------------------
>>  Append  (cost=0.00..43.90 rows=1 width=8) (actual time=0.006..0.006
>> rows=0 loops=1)
>>    ->  Seq Scan on ab_a3_b3  (cost=0.00..43.90 rows=1 width=8) (actual
>> time=0.005..0.005 rows=0 loops=1)
>>          Filter: ((a = 3) AND (b = 3))
>>  Planning time: 0.588 ms
>>  Execution time: 0.043 ms
>> (5 rows)
>
> I think the EXPLAIN ANALYZE input should show something attached to
> the Append node so that we can tell that partition pruning is in use.
> I'm not sure if that is as simple as "Run-Time Partition Pruning: Yes"
> or if we can give a few more useful details.

It already does. Anything subnode with "(never executed)" was pruned
at runtime. Do we really need anything else to tell us that?

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services