From: | Alban Hertroys <haramrae(at)gmail(dot)com> |
---|---|
To: | Soni M <diptatapa(at)gmail(dot)com> |
Cc: | David G Johnston <david(dot)g(dot)johnston(at)gmail(dot)com>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Query planner question |
Date: | 2014-08-22 14:10:14 |
Message-ID: | CAF-3MvNxh9YgHq9eKXYRHat=0+EcDABhsN8OaTMOF3dDjFabHg@mail.gmail.com |
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Lists: | pgsql-general |
On 22 August 2014 14:26, Soni M <diptatapa(at)gmail(dot)com> wrote:
> Currently we have only latest_transmission_id as FK, described here :
> TABLE "ticket" CONSTRAINT "fkcbe86b0c6ddac9e" FOREIGN KEY
> (latest_transmission_id) REFERENCES transmission_base(transmission_id)
>
> Change the query to include only FK still result the same:
> explain select t.ticket_id ,
> tb.transmission_id
> from ticket t,
> transmission_base tb
> where t.latest_transmission_id = tb.transmission_id
> and tb.parse_date > ('2014-07-31');
> QUERY PLAN
> ----------------------------------------------------------------------------------------------------------------------------------
> Hash Join (cost=113928.06..2583606.96 rows=200338 width=8)
> Hash Cond: (t.latest_transmission_id = tb.transmission_id)
> -> Seq Scan on ticket t (cost=0.00..1767767.26 rows=69990826 width=8)
> -> Hash (cost=108923.38..108923.38 rows=400374 width=4)
> -> Index Scan using transmission_base_by_parse_date on
> transmission_base tb (cost=0.00..108923.38 rows=400374 width=4)
> Index Cond: (parse_date > '2014-07-31 00:00:00'::timestamp
> without time zone)
> (6 rows)
Do you have an index on ticket (latest_transmission_id)?
--
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.
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