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From Soni M
Subject Query planner question
Date
Msg-id CAAMgDXnx57NMFXcrB7sE72djD4=3+3EPGNPOdEcwhJ0bEdVFXw@mail.gmail.com
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Responses Re: Query planner question  (David G Johnston <david.g.johnston@gmail.com>)
Re: Query planner question  (Jeff Janes <jeff.janes@gmail.com>)
Re: Query planner question  (Jeff Janes <jeff.janes@gmail.com>)
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Hi Everyone,

I have this query :

select t.ticket_id ,
tb.transmission_id
from ticket t,
transmission_base tb
where t.latest_transmission_id = tb.transmission_id
and t.ticket_number = tb.ticket_number
and tb.parse_date > ('2014-07-31');


Indexes on ticket :
    "ticket_pkey" PRIMARY KEY, btree (ticket_id) CLUSTER
    "ticket_by_latest_transmission" btree (latest_transmission_id)
    "ticket_by_ticket_number" btree (ticket_number)

This query only returns some portions of rows from ticket table.
The question is, Why does postgres need to get all the rows from ticket table in order to complete this query?
Can't postgres use indexes to get only needed rows on ticket table?

I try set seqscan to off, but still index scan try to get all rows on ticket table.
Here's the execution plan : http://explain.depesz.com/s/abH2

Thanks

--
Regards,

Soni Maula Harriz

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