Query not using index
От | Kaloyan Iliev |
---|---|
Тема | Query not using index |
Дата | |
Msg-id | 4399500A.4020607@faith.digsys.bg обсуждение исходный текст |
Ответы |
Re: Query not using index
(Jaime Casanova <systemguards@gmail.com>)
Re: Query not using index (Kaloyan Iliev <news1@faith.digsys.bg>) Re: Query not using index (Kaloyan Iliev <kaloyan@mbox.digsys.bg>) |
Список | pgsql-performance |
Hi all, I have a problem with a query which doeson't want to use indexes. I tried to create different indexes but nothing help. Can anyone suggest what index I need. This query is executed 1.5Milion times per day and I need it to be veri fast. I made my test on 8.0.0 beta but the production database is still 7.4.6 so i need suggestions for 7.4.6. I will post the table with the indexes and the query plans. iplog=# \d croute Table "public.croute" Column | Type | Modifiers -----------------+--------------------------+----------- confid | integer | network | cidr | comment | text | router | text | port | text | valid_at | timestamp with time zone | archived_at | timestamp with time zone | Indexes: "croute_netwo" btree (network) WHERE confid > 0 AND archived_at IS NULL "croute_netwokr_valid_at" btree (network, valid_at) "croute_network" btree (network) WHERE archived_at IS NULL "croute_network_all" btree (network) iplog=# select version(); version -------------------------------------------------------------------------------------------------------------- PostgreSQL 8.0.0beta1 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk) (1 row) !!!!!!!!!!!!THIS IS THE QUERY!!!!!!!!!!!!!!!!! customer=> explain analyze SELECT * customer-> FROM croute customer-> WHERE '193.68.0.8/32' <<= network AND customer-> (archived_at is NULL OR archived_at > '17-11-2005') AND customer-> valid_at < '1-12-2005'::date AND customer-> confid > 0; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Seq Scan on croute (cost=0.00..441.62 rows=413 width=102) (actual time=14.131..37.515 rows=1 loops=1) Filter: (('193.68.0.8/32'::cidr <<= network) AND ((archived_at IS NULL) OR (archived_at > '2005-11-17 00:00:00+02'::timestamp with time zone)) AND (valid_at < ('2005-12-01'::date)::timestamp with time zone) AND (confid > 0)) Total runtime: 37.931 ms (3 rows) customer=> select count(*) from croute; count ------- 10066 (1 row) This is the result of the query: confid | network | comment | router | port | valid_at | archived_at | -------+---------------+---------+------+----+-------------------------+-----------+ 19971 | xx.xx.xx.xx/32 | xxxxx | ? | ? | 2005-03-11 00:00:00+02 | | (1 row) And last I try to stop the sequance scan but it doesn't help. I suppose I don't have the right index. iplog=# set enable_seqscan = off; SET iplog=# explain analyze SELECT * iplog-# FROM croute iplog-# WHERE '193.68.0.8/32' <<= network AND iplog-# (archived_at is NULL OR archived_at > '17-11-2005') AND iplog-# valid_at < '1-12-2005'::date AND iplog-# confid > 0; QUERY PLAN -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Seq Scan on croute (cost=100000000.00..100000780.64 rows=1030 width=103) (actual time=29.593..29.819 rows=1 loops=1) Filter: (('193.68.0.8/32'::cidr <<= network) AND ((archived_at IS NULL) OR (archived_at > '2005-11-17 00:00:00+02'::timestamp with time zone)) AND (valid_at < '2005-12-01'::date) AND (confid > 0)) Total runtime: 29.931 ms (3 rows) I try creating one last index on all fields but it doesn't help. iplog=# CREATE INDEX croute_all on croute(network,archived_at,valid_at,confid); CREATE INDEX iplog=# explain analyze SELECT * iplog-# FROM croute iplog-# WHERE '193.68.0.8/32' <<= network AND iplog-# (archived_at is NULL OR archived_at > '17-11-2005') AND iplog-# valid_at < '1-12-2005'::date AND iplog-# confid > 0; QUERY PLAN -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Seq Scan on croute (cost=100000000.00..100000780.64 rows=1030 width=103) (actual time=29.626..29.879 rows=1 loops=1) Filter: (('193.68.0.8/32'::cidr <<= network) AND ((archived_at IS NULL) OR (archived_at > '2005-11-17 00:00:00+02'::timestamp with time zone)) AND (valid_at < '2005-12-01'::date) AND (confid > 0)) Total runtime: 30.060 ms (3 rows) Thanks in advance to all. Kaloyan Iliev
В списке pgsql-performance по дате отправления: