Query Tuning in PostgreSQL [closed] - sql

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I have a query that is running in 17s, but I can not think of a way to optimize this query. Some help is much needed.
EXPLAIN ANALYSE
CREATE materialized VIEW professores_fizeram_planejamentoTEST as
SELECT unities.id as id_escola,
unities.name as nome_escola,
teachers.id as id_professor,
teachers.name as nome_professor,
datas.dia,
COALESCE((SELECT true
FROM lesson_plans
WHERE lesson_plans.teacher_id = teachers.id and
datas.dia between lesson_plans.start_at and lesson_plans.end_at
LIMIT 1), false) as criou_plano_aula,
COALESCE((select true
from content_records
where content_records.teacher_id = teachers.id and
content_records.record_date = datas.dia
limit 1), false) as criou_registro_conteudo
FROM (SELECT i::date as dia,
EXTRACT(year FROM i::date) as ano
FROM generate_series(date_trunc('year', now()), now(), '1 day'::INTERVAL) i
WHERE EXTRACT(dow from i::timestamp) in (1,2,3,4,5)) datas
JOIN (SELECT distinct teacher_id, classroom_id, YEAR
FROM teacher_discipline_classrooms) teacher_discipline_classrooms ON (teacher_discipline_classrooms.year = datas.ano)
JOIN classrooms on (classrooms.id = teacher_discipline_classrooms.classroom_id)
JOIN unities on (unities.id = classrooms.unity_id)
JOIN teachers on (teachers.id = teacher_discipline_classrooms.teacher_id)
WHERE NOT EXISTS(SELECT 1
FROM school_calendars
JOIN school_calendar_events on (school_calendar_events.school_calendar_id = school_calendars.id and
school_calendar_events.event_type = 'no_school' and
datas.dia between school_calendar_events.start_date and school_calendar_events.end_date)
WHERE school_calendars.unity_id = unities.id)
This query returns the following analysis
Nested Loop (cost=143.840..3721.540 rows=38 width=66) (actual time=1.923..17270.125 rows=171231 loops=1)
-> Nested Loop (cost=143.690..1523.510 rows=38 width=41) (actual time=1.744..5996.571 rows=171231 loops=1)
Join Filter: (NOT (delta 3))
Rows Removed by Join Filter: 15249
-> Nested Loop (cost=143.550..203.530 rows=76 width=16) (actual time=1.661..568.049 rows=186480 loops=1)
-> Hash Join (cost=143.270..165.450 rows=76 width=16) (actual time=1.651..183.740 rows=186660 loops=1)
Hash Cond: ((victor.juliet_seven)::double precision = echo_tango('quebec_four'::text, ((alpha_quebec_whiskey.alpha_quebec_whiskey)::date)::timestamp without time zone))
-> HashAggregate (cost=121.700..127.820 rows=612 width=12) (actual time=1.384..3.336 rows=2388 loops=1)
Group Key: victor.foxtrot_six, victor.oscar_kilo, victor.juliet_seven
-> Seq Scan on victor (cost=0.000..94.400 rows=3640 width=12) (actual time=0.004..0.563 rows=3640 loops=1)
-> Hash (cost=21.260..21.260 rows=25 width=8) (actual time=0.256..0.256 rows=180 loops=1)
Buckets: 1024 Batches: 1 Memory Usage: 16kB
-> Function Scan on xray_yankee alpha_quebec_whiskey (cost=0.010..21.260 rows=25 width=8) (actual time=0.081..0.195 rows=180 loops=1)
Filter: (echo_tango('papa'::text, (alpha_quebec_whiskey)::timestamp without time zone) = ANY ('oscar_seven_charlie'::double precision[]))
Rows Removed by Filter: 72
-> Index Scan using echo_victor on uniform (cost=0.280..0.490 rows=1 width=8) (actual time=0.001..0.002 rows=1 loops=186660)
Index Cond: (quebec_seven = victor.oscar_kilo)
-> Index Scan using golf on four (cost=0.140..0.160 rows=1 width=29) (actual time=0.001..0.001 rows=1 loops=186480)
Index Cond: (quebec_seven = uniform.xray_victor)
SubPlan
-> Nested Loop (cost=0.280..34.110 rows=2 width=0) (actual time=0.027..0.027 rows=0 loops=186480)
-> Seq Scan on seven (cost=0.000..1.990 rows=2 width=4) (actual time=0.003..0.008 rows=2 loops=186480)
Filter: (xray_victor = four.quebec_seven)
Rows Removed by Filter: 75
-> Index Scan using alpha_quebec_papa on two (cost=0.280..16.050 rows=1 width=4) (actual time=0.008..0.008 rows=0 loops=372960)
Index Cond: (zulu = seven.quebec_seven)
Filter: (((xray_delta)::text = 'oscar_seven_golf'::text) AND ((alpha_quebec_whiskey.alpha_quebec_whiskey)::date >= foxtrot_three) AND ((alpha_quebec_whiskey.alpha_quebec_whiskey)::date <= lima))
Rows Removed by Filter: 14
-> Index Scan using tango on romeo (cost=0.150..0.200 rows=1 width=29) (actual time=0.001..0.001 rows=1 loops=171231)
Index Cond: (quebec_seven = victor.foxtrot_six)
SubPlan
-> Limit (cost=0.000..20.600 rows=1 width=0) (actual time=0.048..0.048 rows=0 loops=171231)
-> Seq Scan on five (cost=0.000..20.600 rows=1 width=0) (actual time=0.045..0.045 rows=0 loops=171231)
Filter: ((foxtrot_six = romeo.quebec_seven) AND ((alpha_quebec_whiskey.alpha_quebec_whiskey)::date >= oscar_echo) AND ((alpha_quebec_whiskey.alpha_quebec_whiskey)::date <= xray_three))
Rows Removed by Filter: 246
SubPlan
-> Limit (cost=4.810..37.030 rows=1 width=0) (actual time=0.015..0.015 rows=0 loops=171231)
-> Bitmap Heap Scan on whiskey (cost=4.810..37.030 rows=1 width=0) (actual time=0.011..0.011 rows=0 loops=171231)
Recheck Cond: (foxtrot_six = romeo.quebec_seven)
Filter: (foxtrot_tango = (alpha_quebec_whiskey.alpha_quebec_whiskey)::date)
Rows Removed by Filter: 28
Heap Blocks: exact=258248
-> Bitmap Index Scan on juliet_bravo (cost=0.000..4.810 rows=70 width=0) (actual time=0.003..0.003 rows=37 loops=171231)
Index Cond: (foxtrot_six = romeo.quebec_seven)
EXPLAIN 1 - RESULT
EXPLAIN 2 - RESULT
Thanks you.

Answer 1

no, we wont!
sanitize your query (add aliases, and use them, for instance)
COALESCE((SELECT true FROM lesson_plans WHERE lesson_plans.teacher_id = teachers.id and datas.dia between lesson_plans.start_at and lesson_plans.end_at LIMIT 1), false) as criou_plano_aula
... can be replaced by a simple EXISTS(subquery)
your outer query only refers to {unities,teachers,datas}, the rest of the tables are merely junction tables.
if there is a difference in the queryplan between expected <-->observed, your statistics are wrong.
the function scan on generate_series() spoils the queryplan. Better use a material calendartable, which could be indexed & countable.
always add the tuning parameters and an estimate of the cardinalities to the question. These are not details.

Answer 2

This is not an answer, but a comment that doesn't fit in the comments section. If you want to speed up your query please add some information:
First, please include the execution plan. This will tell us what's going on fast.
Also, please post:
Existing indexes on lessons_plans.
Existing indexes on content_records.
Rows on teacher_discipline_classrooms.
Existing indexes on teacher_discipline_classrooms.
Existing indexes on classrooms.
Existing indexes on unities.
indexes on teachers.
Existing indexes on shool_calendars.