Index not used in query. Why? - Mailing list pgsql-performance
| From | Andrei Bintintan |
|---|---|
| Subject | Index not used in query. Why? |
| Date | |
| Msg-id | 0bef01c4b5f8$70026ae0$0b00a8c0@forge Whole thread Raw |
| Responses |
Re: Index not used in query. Why?
|
| List | pgsql-performance |
Hi to all! I have the following query. The execution time is very big, it
doesn't use the indexes and I don't understand why...
SELECT count(o.id) FROM orders o
INNER JOIN report r ON o.id=r.id_order
INNER JOIN status s ON o.id_status=s.id
INNER JOIN contact c ON o.id_ag=c.id
INNER JOIN endkunde e ON
o.id_endkunde=e.id
INNER JOIN zufriden z ON
r.id_zufriden=z.id
INNER JOIN plannung v ON
v.id=o.id_plannung
INNER JOIN mpsworker w ON
v.id_worker=w.id
INNER JOIN person p ON p.id = w.id_person
WHERE o.id_status > 3
The query explain:
Aggregate (cost=32027.38..32027.38 rows=1 width=4)
-> Hash Join (cost=23182.06..31944.82 rows=33022 width=4)
Hash Cond: ("outer".id_person = "inner".id)
-> Hash Join (cost=23179.42..31446.85 rows=33022 width=8)
Hash Cond: ("outer".id_endkunde = "inner".id)
-> Hash Join (cost=21873.54..28891.42 rows=33022 width=12)
Hash Cond: ("outer".id_ag = "inner".id)
-> Hash Join (cost=21710.05..28067.50 rows=33021
width=16)
Hash Cond: ("outer".id_status = "inner".id)
-> Hash Join (cost=21708.97..27571.11 rows=33021
width=20)
Hash Cond: ("outer".id_worker = "inner".id)
-> Hash Join (cost=21707.49..27074.31
rows=33021 width=20)
Hash Cond: ("outer".id_zufriden =
"inner".id)
-> Hash Join
(cost=21706.34..26564.09 rows=35772 width=24)
Hash Cond: ("outer".id_plannung
= "inner".id)
-> Hash Join
(cost=20447.15..23674.04 rows=35771 width=24)
Hash Cond: ("outer".id =
"inner".id_order)
-> Seq Scan on orders o
(cost=0.00..1770.67 rows=36967 width=20)
Filter: (id_status >
3)
-> Hash
(cost=20208.32..20208.32 rows=37132 width=8)
-> Seq Scan on
report r (cost=0.00..20208.32 rows=37132 width=8)
-> Hash (cost=913.15..913.15
rows=54015 width=8)
-> Seq Scan on plannung v
(cost=0.00..913.15 rows=54015 width=8)
-> Hash (cost=1.12..1.12 rows=12
width=4)
-> Seq Scan on zufriden z
(cost=0.00..1.12 rows=12 width=4)
-> Hash (cost=1.39..1.39 rows=39 width=8)
-> Seq Scan on mpsworker w
(cost=0.00..1.39 rows=39 width=8)
-> Hash (cost=1.06..1.06 rows=6 width=4)
-> Seq Scan on status s (cost=0.00..1.06
rows=6 width=4)
-> Hash (cost=153.19..153.19 rows=4119 width=4)
-> Seq Scan on contact c (cost=0.00..153.19
rows=4119 width=4)
-> Hash (cost=1077.91..1077.91 rows=38391 width=4)
-> Seq Scan on endkunde e (cost=0.00..1077.91
rows=38391 width=4)
-> Hash (cost=2.51..2.51 rows=51 width=4)
-> Seq Scan on person p (cost=0.00..2.51 rows=51 width=4)
As you can see, no index is used.I made everywhere indexes where the jons
are made. If I use the following query the indexes are used:
SELECT count(o.id) FROM orders o
INNER JOIN report r ON o.id=r.id_order
INNER JOIN status s ON o.id_status=s.id
INNER JOIN contact c ON o.id_ag=c.id
INNER JOIN endkunde e ON
o.id_endkunde=e.id
INNER JOIN zufriden z ON
r.id_zufriden=z.id
INNER JOIN plannung v ON
v.id=o.id_plannung
INNER JOIN mpsworker w ON
v.id_worker=w.id
INNER JOIN person p ON p.id = w.id_person
WHERE o.id_status =4
Aggregate (cost=985.55..985.55 rows=1 width=4)
-> Hash Join (cost=5.28..985.42 rows=50 width=4)
Hash Cond: ("outer".id_person = "inner".id)
-> Hash Join (cost=2.64..982.03 rows=50 width=8)
Hash Cond: ("outer".id_worker = "inner".id)
-> Nested Loop (cost=1.15..979.79 rows=50 width=8)
-> Nested Loop (cost=1.15..769.64 rows=49 width=8)
-> Nested Loop (cost=1.15..535.57 rows=48
width=12)
-> Seq Scan on status s (cost=0.00..1.07
rows=1 width=4)
Filter: (4 = id)
-> Nested Loop (cost=1.15..534.01 rows=48
width=16)
-> Hash Join (cost=1.15..366.37
rows=47 width=20)
Hash Cond: ("outer".id_zufriden
= "inner".id)
-> Nested Loop
(cost=0.00..364.48 rows=51 width=24)
-> Index Scan using
orders_id_status_idx on orders o (cost=0.00..69.55 rows=52 width=20)
Index Cond:
(id_status = 4)
-> Index Scan using
report_id_order_idx on report r (cost=0.00..5.66 rows=1 width=8)
Index Cond:
("outer".id = r.id_order)
-> Hash (cost=1.12..1.12
rows=12 width=4)
-> Seq Scan on zufriden z
(cost=0.00..1.12 rows=12 width=4)
-> Index Scan using endkunde_pkey on
endkunde e (cost=0.00..3.55 rows=1 width=4)
Index Cond: ("outer".id_endkunde
= e.id)
-> Index Scan using contact_pkey on contact c
(cost=0.00..4.86 rows=1 width=4)
Index Cond: ("outer".id_ag = c.id)
-> Index Scan using plannung_pkey on plannung v
(cost=0.00..4.28 rows=1 width=8)
Index Cond: (v.id = "outer".id_plannung)
-> Hash (cost=1.39..1.39 rows=39 width=8)
-> Seq Scan on mpsworker w (cost=0.00..1.39 rows=39
width=8)
-> Hash (cost=2.51..2.51 rows=51 width=4)
-> Seq Scan on person p (cost=0.00..2.51 rows=51 width=4)
Best regards,
Andy.
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