Hi, On 2018/12/05 6:55, Alvaro Herrera wrote: > I noticed another interesting thing, which is that if I modify the query > to actually reference some partition that I do have (as opposed to the > above, which just takes 30s to prune everything) the plan is mighty > curious ... if only because in one of the Append nodes, partitions have > not been pruned as they should. > > So, at least two bugs here, > 1. the equivalence-class related slowness, > 2. the lack of pruning > > QUERY PLAN > ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > Hash Join (cost=1159.13..25423.65 rows=1 width=24) > Hash Cond: (abs((p.plusalesprice - p_875.plusalesprice)) = (max(abs((p_877.plusalesprice - p_879.plusalesprice))))) > -> Nested Loop (cost=1000.00..25264.52 rows=1 width=20) > Join Filter: ((p.loccd = p_875.loccd) AND (p.fecha = p_875.fecha)) > -> Gather (cost=1000.00..25154.38 rows=875 width=16) > Workers Planned: 2 > -> Parallel Append (cost=0.00..24066.88 rows=875 width=16) > -> Parallel Seq Scan on precio_125 p (cost=0.00..27.50 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1999-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) [ Parallel SeqScan on precio_126 to precio_998 ] > -> Parallel Seq Scan on precio_999 p_874 (cost=0.00..27.50 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1999-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) As you can see from the "Filter: " property above, the baserestrictinfo of this Append's parent relation is: BETWEEN '1990-05-06' AND '1999-05-07' which selects partitions for all days from '1990-05-06' (precio_125) up to '1992-09-26' (precio_999). > -> Materialize (cost=0.00..79.52 rows=2 width=16) > -> Append (cost=0.00..79.51 rows=2 width=16) > -> Seq Scan on precio_125 p_875 (cost=0.00..39.75 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1990-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) > -> Seq Scan on precio_126 p_876 (cost=0.00..39.75 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1990-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) Whereas for this Append, it is BETWEEN '1990-05-06' AND '1990-05-07'. > -> Hash (cost=159.12..159.12 rows=1 width=4) > -> Aggregate (cost=159.10..159.11 rows=1 width=4) > -> Nested Loop (cost=0.00..159.10 rows=1 width=8) > Join Filter: ((p_877.loccd = p_879.loccd) AND (p_877.fecha = p_879.fecha)) > -> Append (cost=0.00..79.51 rows=2 width=16) > -> Seq Scan on precio_125 p_877 (cost=0.00..39.75 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1990-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) > -> Seq Scan on precio_126 p_878 (cost=0.00..39.75 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1990-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) > -> Materialize (cost=0.00..79.52 rows=2 width=16) > -> Append (cost=0.00..79.51 rows=2 width=16) > -> Seq Scan on precio_125 p_879 (cost=0.00..39.75 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1990-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) > -> Seq Scan on precio_126 p_880 (cost=0.00..39.75 rows=1 width=16) > Filter: ((fecha >= '1990-05-06 00:00:00'::timestamp without time zone) AND (fecha <= '1990-05-07 00:00:00'::timestamp without time zone) AND (pluid = 2)) And also for these two Appends. So, I don't think there's anything funny going on with pruning here, maybe just a typo in the query (1999 looks very much like 1990 to miss the typo maybe.) I fixed the query to change '1999-05-07' to '1990-05-07' of the first Append's parent relation and I get the following planning time with the patch I posted above with 2 partitions selected under each Append as expected. Planning Time: 536.947 ms Execution Time: 1.304 ms (31 rows) Even without changing 1999 to 1990, the planning time with the patch is: Planning Time: 4669.685 ms Execution Time: 110.506 ms (1777 rows) Thanks, Amit
