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Re: SQL command speed

From: mig(at)utdt(dot)edu
To: klcollins(at)wsicorp(dot)com
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: SQL command speed
Date: 2000-05-18 19:38:29
Message-ID: 200005181938.QAA04835@ant.utdt (view raw, whole thread or download thread mbox)
Lists: pgsql-sql
I believe the PostgreSQL optimizer is fooled by many ORs and switches
to sequential scans: it cannot estimate properly the quantity of
results that will be returned.

Try it in one go, as

    $sql = "SELECT notam_id, TO_CHAR(full_issue_date, 'DD-MON-YYYY 
        FROM notam_details
          item_a IN 
The optimizer should (I think) like this better and use the indices,
without requiring that you iterate the queries from the frontend.

As I am trying to learn these things too, I will appreciate knowing
about the result of your tests: please keep me posted.


Miguel Sofer

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Subject: Re: SQL command speed
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