Tomasz Myrta <[EMAIL PROTECTED]> writes:
If I add "and k.id_trasy=lt.id_trasy" into where clause (duplicate), the query works fine.
Define "works fine", please (again, EXPLAIN ANALYZE would be a nice concrete description).
Sorry, I thought the wrong case would be enough. In first case (the worse one) I had: Total runtime: 678.31 msec
After my changes I got:
explain analyze select *
from plany pl
join linia_trasy lt using (id_linii)
join kursy k on (k.event_date=pl.begindate+lt.offset and k.id_trasy=lt.id_trasy)
where pl.id_planu=508
and k.id_trasy=lt.id_trasy;
^^^^^^^^^^^^^^^^^^^^^^^^^^^
QUERY PLAN
--------------------------------------------------------
Nested Loop (cost=0.00..94.43 rows=2 width=40) (actual time=2.97..77.55 rows=5 loops=1)
Join Filter: ("inner".event_date = ("outer".begindate + "outer".offset))
-> Nested Loop (cost=0.00..5.81 rows=7 width=29) (actual time=0.15..0.41 rows=7 loops=1)
Join Filter: ("outer".id_linii = "inner".id_linii)
-> Index Scan using plany_pkey on plany pl (cost=0.00..4.49 rows=1 width=17) (actual time=0.09..0.10 rows=1 loops=1)
Index Cond: (id_planu = 508)
-> Seq Scan on linia_trasy lt (cost=0.00..1.14 rows=14 width=12) (actual time=0.02..0.15 rows=14 loops=1)
-> Index Scan using kursy_pkey on kursy k (cost=0.00..7.62 rows=288 width=11) (actual time=0.05..8.01 rows=533 loops=7)
Index Cond: ((k.id_trasy = "outer".id_trasy) AND (k.id_trasy = "outer".id_trasy))
Total runtime: 78.01 msec
It's much better now (10x faster), but I've just found this plan still isn't as I want to have. I wish I could have index usage on both fields, it means:
Index Cond: ((k.id_trasy = "outer".id_trasy) AND (("inner".event_date = ("outer".begindate + "outer".offset)
Regards, Tomasz Myrta
---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
