pg.ddx.io pgsql-performance@postgresql.org mailing list archive help / color / mirror / Atom feed From: Kaloyan Iliev Iliev <kaloyan@digsys.bg>
To: pgsql-performance@postgresql.org
Subject: Re: Query Optimization
Date: Thu, 08 Apr 2010 16:41:16 +0300
Message-ID: <4BBDDCFC.5070901@digsys.bg> (raw )
In-Reply-To: <4BBDD2F3.7030701@digsys.bg >
References: <4BBDD2F3.7030701@digsys.bg >
Sorry for the noise.
I make vacuum analyze and the problem is solved.
Kaloyan Iliev
Kaloyan Iliev Iliev wrote:
> Hi,
> Can anyone suggest why this query so slow.
>
> SELECT version();
> version
> ---------------------------------------------------------------------------------------------------------
>
> PostgreSQL 8.4.2 on i386-portbld-freebsd7.2, compiled by GCC cc (GCC)
> 4.2.1 20070719 [FreeBSD], 32-bit
> (1 row)
> explain analyze SELECT DT.value,
> DT.meassure_date,
> DT.ms_status_id as status_id,
> S.descr_bg as status_bg,
> S.descr_en as status_en,
> VT.id as value_type_id,
> VT.descr_en as value_type_en,
> VT.descr_bg as value_type_bg,
> T.unit as value_type_unit,
> T.name as general_value_type,
> T.ms_db_type_id
> FROM
> ms_data AS DT,
> ms_statuses AS S,
> ms_value_types AS VT,
> ms_types AS T,
> ms_commands_history AS CH
> WHERE DT.ms_value_type_id = 88 AND
> DT.meassure_date >= '2010-04-01 1:00:00' AND
> DT.meassure_date <= '2010-04-01 1:10:00' AND
> DT.ms_command_history_id = CH.id AND
> CH.ms_device_id = 7 AND
> DT.ms_value_type_id = VT.id AND
> VT.ms_type_id = T.id AND
> DT.ms_status_id = S.id
> GROUP BY value,
> meassure_date,
> status_id,
> status_bg,
> status_en,
> value_type_id,
> value_type_en,
> value_type_bg,
> value_type_unit,
> general_value_type,
> ms_db_type_id
> ORDER BY meassure_date DESC;
> QUERY PLAN
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Group (cost=23.93..23.96 rows=1 width=229) (actual
> time=63274.021..63274.021 rows=0
> loops=1)
> -> Sort (cost=23.93..23.94 rows=1 width=229) (actual
> time=63274.016..63274.016 rows=0 loops=1)
> Sort Key: dt.meassure_date, dt.value, dt.ms_status_id, s.descr_bg,
> s.descr_en, vt.id, vt.descr_en, vt.descr_bg, t.unit, t.name,
> t.ms_db_type_id Sort Method: quicksort Memory: 17kB
> -> Nested Loop (cost=0.00..23.92 rows=1 width=229) (actual
> time=63273.982..63273.982 rows=0
> loops=1)
> -> Nested Loop (cost=0.00..19.64 rows=1 width=165)
> (actual time=63273.977..63273.977 rows=0
> loops=1)
> -> Nested Loop (cost=0.00..15.36 rows=1 width=101)
> (actual time=63273.974..63273.974 rows=0
> loops=1)
> -> Nested Loop (cost=0.00..11.08 rows=1 width=23)
> (actual time=63273.970..63273.970 rows=0
> loops=1)
> -> Index Scan using
> ms_commands_history_ms_device_id_idx on ms_commands_history ch
> (cost=0.00..4.33 rows=1 width=8) (actual time=0.163..25254.004
> rows=9807 loops=1)
> Index Cond: (ms_device_id = 7)
> -> Index Scan using
> ms_data_ms_command_history_id_idx on ms_data dt (cost=0.00..6.74
> rows=1 width=31) (actual time=3.868..3.868 rows=0 loops=9807)
> Index Cond:
> (dt.ms_command_history_id = ch.id)
> Filter: ((dt.meassure_date >=
> '2010-04-01 01:00:00'::timestamp without time zone) AND
> (dt.meassure_date <= '2010-04-01 01:10:00'::timestamp without time
> zone) AND (dt.ms_value_type_id = 88))
> -> Index Scan using ms_value_types_pkey on
> ms_value_types vt (cost=0.00..4.27 rows=1 width=82) (never
> executed) Index Cond:
> (vt.id = 88)
> -> Index Scan using ms_types_pkey on ms_types t
> (cost=0.00..4.27 rows=1 width=72) (never
> executed)
> Index Cond: (t.id = vt.ms_type_id)
> -> Index Scan using ms_statuses_pkey on ms_statuses s
> (cost=0.00..4.27 rows=1 width=68) (never
> executed) Index
> Cond: (s.id = dt.ms_status_id)
> Total runtime: 63274.256 ms
> Thanks in advance.
>
> Kaloyan Iliev
>
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To: pgsql-performance@postgresql.org
Cc: kaloyan@digsys.bg
Subject: Re: Query Optimization
In-Reply-To: <4BBDDCFC.5070901@digsys.bg>
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