Hi,
The index doesn't cost you so much, seq SEQ Scan actully does:
Seq Scan on isbns_a_descubrir
(cost=0.00..8067.91 rows=1 width=21) (actual time=30.044..30.044 rows=1
loops=2025)
This seq scan is called once for every row of librosdisponibilidadtemp
which passes the WHERE condition.
So Here "Index Scan using
librosdisponibilidadtemp_idx_proceso on librosdisponibilidadtemp
(cost=
1.01..133557993.56 rows=2068 width=21) (actual
time=5722.607..790552.588 rows=9 loops=1)" it
says how much it will cost you to calculate the upper seq scan and the
seq scan on (Seq Scan on
raizpaises) and the index scan on libros.
I suggest you to create index on table isbns_a_descubrir over
column isbn. This will hurry the query.
And use join instead of IN for table raizpaises. This should also save
some time.
Regards,
Kaloyan Iliev
ave this query:
SELECT DISTINCT isbn, CURRENT_TIMESTAMP, 1
FROM librosdisponibilidadtemp
WHERE proceso = ai_proceso
AND gen_isbn_pais(isbn) IN (SELECT pais FROM raizpaises)
AND NOT EXISTS
( SELECT isbn
FROM libros
WHERE isbn = librosdisponibilidadtemp.isbn)
AND NOT EXISTS
( SELECT isbn
FROM isbns_a_descubrir
WHERE isbn = librosdisponibilidadtemp.isbn);
and the plan execution is
Unique (cost=133558107.45..133558128.13 rows=414 width=21) (actual
time=
790552.899..790553.098 rows=9 loops=1)
-> Sort (cost=133558107.45..133558112.62 rows=2068 width=21)
(actual time=790552.882..790552.944 rows=9 loops=1)
Sort Key: isbn, now(), 1
-> Index Scan using librosdisponibilidadtemp_idx_proceso on
librosdisponibilidadtemp (cost=
1.01..133557993.56 rows=2068 width=21) (actual
time=5722.607..790552.588 rows=9 loops=1)
Index Cond: (proceso = 28465)
Filter: ((hashed subplan) AND (NOT (subplan)) AND (NOT
(subplan)))
SubPlan
-> Seq Scan on isbns_a_descubrir
(cost=0.00..8067.91 rows=1 width=21) (actual time=30.044..30.044 rows=1
loops=2025)
Filter: ((isbn)::bpchar = $1)
-> Index Scan using "libros_idx_ISBN" on libros
(cost=0.00..5.95 rows=1 width=21) (actual time=12.938..12.938 rows=1
loops=50512)
Index Cond: (isbn = $1)
-> Seq Scan on raizpaises (cost=
0.00..1.01 rows=1 width=10) (actual time=0.764..0.871 rows=1 loops=1)
Total runtime: 790553.561 ms
The libros table has 1200000 regs.
The isbns_a_descubrir table has 300000 regs.
The librosdisponibilidadtemp table has 50000 regs.
does anybody can explain me, why using index
ibrosdisponibilidadtemp_idx_proceso is so slow and the others
conditions are good enough
Thanks everybody
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