Como leeer el explain analyze

From: Edwin Quijada <listas_quijada(at)hotmail(dot)com>
To: <pgsql-es-ayuda(at)postgresql(dot)org>
Subject: Como leeer el explain analyze
Date: 2008-12-30 14:53:26
Message-ID: BLU137-W1333ACF44EFAA7CE8CDC3BE3E70@phx.gbl
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Hola!
Me estoy eneredando con una consulta que esta muy lenta y estoy tratando de entender el asunto del explain analyze para ver como mejorar el performance pero la verdad entiendo poco la informacion que ahi ofrece.
No existe alguna informacion de como se podria interpretar de una mejor forma esta informacion de forma tal que podamos analizar cualquier consulta?

Ejemplo:
QUERY PLAN
Limit (cost=14910.15..14910.15 rows=1 width=20) (actual time=0.093..0.093 rows=0 loops=1)
InitPlan
-> Seq Scan on tsys_leads_lists l2 (cost=0.00..178.34 rows=1 width=0) (actual time=0.038..0.038 rows=1 loops=1)
Filter: ((fsys_attempts> 0) AND (fsys_loaddatetime = '2008-12-22 12:08:09'::timestamp without time zone))
-> Sort (cost=14731.80..14733.92 rows=847 width=20) (actual time=0.091..0.091 rows=0 loops=1)
Sort Key: l.fsys_lastdial_datetime, l.fsys_id_record
Sort Method: quicksort Memory: 17kB
-> Result (cost=0.00..14727.57 rows=847 width=20) (actual time=0.041..0.041 rows=0 loops=1)
One-Time Filter: (NOT $2)
-> Nested Loop (cost=0.00..14727.57 rows=847 width=20) (never executed)
-> Seq Scan on tsys_leads_original o (cost=0.00..9238.67 rows=945 width=4) (never executed)
Filter: ((fsys_id_project = 102) AND (aall_general.asys_geography_get_timezone1_datetime(fsys_phone1)>= ((((((aall_general.asys_geography_get_timezone1_datetime(fsys_phone1))::date)::character varying)::text || ' '::text) || '09:00:00 AM'::text))::timestamp without time zone) AND (aall_general.asys_geography_get_timezone1_datetime(fsys_phone1) <= ((((((aall_general.asys_geography_get_timezone1_datetime(fsys_phone1))::date)::character varying)::text || ' '::text) || '09:00:00 PM'::text))::timestamp without time zone))
-> Index Scan using tsys_leads_lists_idx on tsys_leads_lists l (cost=0.00..5.80 rows=1 width=28) (never executed)
Index Cond: (l.fsys_unoid = o.fsys_unoid)
Filter: ((l.fsys_loaddatetime = '2008-12-22 12:08:09'::timestamp without time zone) AND (l.fsys_lead_activation_mark = 1) AND (l.fsys_attempts = 0) AND ((l.fsys_lastdial_datetime IS NULL) OR (l.fsys_lastdial_datetime < (now())::date)) AND ((l.fsys_active = 1) OR ((l.fsys_active = 0) AND (l.fsys_lastget_datetime < (now())::date))) AND ((l.fsys_code IS NULL) OR ((l.fsys_code)::text = ''::text) OR (subplan)))
SubPlan
-> Seq Scan on tsys_script_dispositions d (cost=0.00..5.09 rows=1 width=0) (never executed)
Filter: ((($0)::text = (fsys_code)::text) AND (fsys_done = 0))
Total runtime: 0.200 ms

*-------------------------------------------------------*
*-Edwin Quijada
*-Developer DataBase
*-JQ Microsistemas
*-809-849-8087

* " Si deseas lograr cosas excepcionales debes de hacer cosas fuera de lo comun"
*-------------------------------------------------------*

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