#	exclusive	inclusive	rows x	rows	loops	node
1.	0.041	613.992	↑ 1.0	10	1	→ Limit (cost=37.44..1234.99 rows=10 width=223) (actual time=365.920..613.992 rows=10 loops=1)
2.	0.084	613.951	↑ 612.9	10	1	→ Nested Loop (cost=37.44..734017.88 rows=6129 width=223) (actual time=365.916..613.951 rows=10 loops=1)
3.	0.106	613.737	↑ 612.9	10	1	→ Nested Loop Left Join (cost=37.44..716534.78 rows=6129 width=197) (actual time=365.897..613.737 rows=10 loops=1)
4.	1.424	613.511	↑ 612.9	10	1	→ Nested Loop Left Join (cost=37.44..703885.24 rows=6129 width=161) (actual time=365.880..613.511 rows=10 loops=1) Filter: ((core_rating.last_displayed IS NULL) AND (((core_rating.type = 1) AND (core_rating.rating IS NULL)) OR (core_rating.user_id IS NULL)))
5.	0.312	0.312	↑ 221.8	75	1	→ Index Scan Backward using core_film_popularity on core_film (cost=0.00..14188.60 rows=16634 width=78) (actual time=0.020..0.312 rows=75 loops=1)
6.	1.800	611.775	↓ 3.0	3	75	→ Bitmap Heap Scan on core_rating (cost=37.44..41.45 rows=1 width=83) (actual time=8.149..8.157 rows=3 loops=75) Recheck Cond: ((core_film.parent_id = core_rating.parent_id) AND (core_rating.user_id = 3))
7.	33.375	609.975	↓ 0.0	0	75	→ BitmapAnd (cost=37.44..37.44 rows=1 width=0) (actual time=8.133..8.133 rows=0 loops=75)
8.	78.975	78.975	↓ 2.0	1436	75	→ Bitmap Index Scan on core_rating_parent_id (cost=0.00..8.98 rows=715 width=0) (actual time=1.053..1.053 rows=1436 loops=75) Index Cond: (core_film.parent_id = core_rating.parent_id)
9.	497.625	497.625	↓ 6.7	16209	75	→ Bitmap Index Scan on core_rating_user_id (cost=0.00..27.60 rows=2431 width=0) (actual time=6.635..6.635 rows=16209 loops=75) Index Cond: (core_rating.user_id = 3)
10.	0.120	0.120	↑ 1.0	1	10	→ Index Scan using filmbasket_basketitem_ids on filmbasket_basketitem (cost=0.00..2.05 rows=1 width=36) (actual time=0.011..0.012 rows=1 loops=10) Index Cond: ((core_film.parent_id = filmbasket_basketitem.film_id) AND (filmbasket_basketitem.user_id = 3))
11.	0.130	0.130	↑ 1.0	1	10	→ Index Scan using core_object_pkey on core_object (cost=0.00..2.84 rows=1 width=26) (actual time=0.011..0.013 rows=1 loops=10) Index Cond: (core_object.id = core_film.parent_id)

explain analyze SELECT * FROM "core_film" INNER JOIN "core_object" ON ("core_film"."parent_id" = "core_object"."id") LEFT OUTER JOIN "filmbasket_basketitem" ON ("core_film"."parent_id" = "filmbasket_basketitem"."film_id" and "filmbasket_basketitem"."user_id" = 3) LEFT OUTER JOIN "core_rating" ON ("core_film"."parent_id" = "core_rating"."parent_id" and "core_rating"."user_id" = 3) WHERE ( ("core_rating"."type"=1 AND "core_rating"."rating" IS NULL) OR "core_rating"."user_id" IS NULL) AND "core_rating"."last_displayed" IS NULL ORDER BY "core_film"."popularity" DESC LIMIT 10 ;
                                                                                QUERY PLAN                                                                                 
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=37.44..1234.99 rows=10 width=223) (actual time=365.920..613.992 rows=10 loops=1)
   ->  Nested Loop  (cost=37.44..734017.88 rows=6129 width=223) (actual time=365.916..613.951 rows=10 loops=1)
         ->  Nested Loop Left Join  (cost=37.44..716534.78 rows=6129 width=197) (actual time=365.897..613.737 rows=10 loops=1)
               ->  Nested Loop Left Join  (cost=37.44..703885.24 rows=6129 width=161) (actual time=365.880..613.511 rows=10 loops=1)
                     Filter: ((core_rating.last_displayed IS NULL) AND (((core_rating.type = 1) AND (core_rating.rating IS NULL)) OR (core_rating.user_id IS NULL)))
                     ->  Index Scan Backward using core_film_popularity on core_film  (cost=0.00..14188.60 rows=16634 width=78) (actual time=0.020..0.312 rows=75 loops=1)
                     ->  Bitmap Heap Scan on core_rating  (cost=37.44..41.45 rows=1 width=83) (actual time=8.149..8.157 rows=3 loops=75)
                           Recheck Cond: ((core_film.parent_id = core_rating.parent_id) AND (core_rating.user_id = 3))
                           ->  BitmapAnd  (cost=37.44..37.44 rows=1 width=0) (actual time=8.133..8.133 rows=0 loops=75)
                                 ->  Bitmap Index Scan on core_rating_parent_id  (cost=0.00..8.98 rows=715 width=0) (actual time=1.053..1.053 rows=1436 loops=75)
                                       Index Cond: (core_film.parent_id = core_rating.parent_id)
                                 ->  Bitmap Index Scan on core_rating_user_id  (cost=0.00..27.60 rows=2431 width=0) (actual time=6.635..6.635 rows=16209 loops=75)
                                       Index Cond: (core_rating.user_id = 3)
               ->  Index Scan using filmbasket_basketitem_ids on filmbasket_basketitem  (cost=0.00..2.05 rows=1 width=36) (actual time=0.011..0.012 rows=1 loops=10)
                     Index Cond: ((core_film.parent_id = filmbasket_basketitem.film_id) AND (filmbasket_basketitem.user_id = 3))
         ->  Index Scan using core_object_pkey on core_object  (cost=0.00..2.84 rows=1 width=26) (actual time=0.011..0.013 rows=1 loops=10)
               Index Cond: (core_object.id = core_film.parent_id)
 Total runtime: 614.209 ms
(18 rows)

Per node type stats

node type	count	sum of times	% of query
Bitmap Heap Scan	1	1.800 ms	0.3 %
Bitmap Index Scan	2	576.600 ms	93.9 %
BitmapAnd	1	33.375 ms	5.4 %
Index Scan	2	0.250 ms	0.0 %
Index Scan Backward	1	0.312 ms	0.1 %
Limit	1	0.041 ms	0.0 %
Nested Loop	1	0.084 ms	0.0 %
Nested Loop Left Join	2	1.530 ms	0.2 %

Per table stats

Table name	Scan count	Total time	% of query
scan type	count	sum of times	% of table
core_film	1	0.312 ms	0.1 %
Index Scan Backward	1	0.312 ms	100.0 %
core_object	1	0.130 ms	0.0 %
Index Scan	1	0.130 ms	100.0 %
core_rating	1	1.800 ms	0.3 %
Bitmap Heap Scan	1	1.800 ms	100.0 %
filmbasket_basketitem	1	0.120 ms	0.0 %
Index Scan	1	0.120 ms	100.0 %

explain.depesz.com

A tool for finding a real cause for slow queries.

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Per node type stats

Per table stats