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From luis.roberto@siscobra.com.br
Subject Re: Join optimization
Date
Msg-id 1436239160.11622485.1594493964776.JavaMail.zimbra@siscobra.com.br
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In response to Re: Join optimization  (Fabrízio de Royes Mello <fabrizio@timbira.com.br>)
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I'm sorry for the bad example.


I don't understand oracle's execution plan very well, but it doesn't seem to be hitting the Users table...

De: "Fabrízio de Royes Mello" <fabrizio@timbira.com.br>
Para: "luis.roberto" <luis.roberto@siscobra.com.br>
Cc: "pgsql-general" <pgsql-general@lists.postgresql.org>
Enviadas: Sábado, 11 de julho de 2020 15:24:04
Assunto: Re: Join optimization


Em sáb, 11 de jul de 2020 às 14:20, <luis.roberto@siscobra.com.br> escreveu:
Hi!

Recently on a blogpost [1] I saw that Oracle was able to "optimize" a join strategy by completely eliminating access to a table.

Heres the execution on Oracle 18c [2] and PostgreSQL 13 (beta) [3].

Is there a fundamental reason why PG can't do the same? 

It does... did you see the “never executed” notice on the Postgres explain output?

Regards,


--
   Fabrízio de Royes Mello         Timbira - http://www.timbira.com.br/
   PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento

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