On Wed, 17 Apr 2019 at 13:13, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > When you see this: > > explain select * from t1 where dt = current_date + 400; > QUERY PLAN > ──────────────────────────────────────────────────────────── > Append (cost=0.00..198.42 rows=44 width=8) > Subplans Removed: 3 > -> Seq Scan on t1_1 (cost=0.00..49.55 rows=11 width=8) > Filter: (dt = (CURRENT_DATE + 400)) > (4 rows) > > Doesn't this give an impression that t1_1 *matches* the WHERE condition > where it clearly doesn't? IMO, contorting explain.c to show an empty > Append like what Hosoya-san suggests doesn't sound too bad given that the > first reaction to seeing the above result is to think it's a bug of > partition pruning.
Where do you think the output list for EXPLAIN VERBOSE should put the output column list in this case? On the Append node, or just not show them? -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
