Thread: Is there any documentation on explain?

Is there any documentation on explain?

From
Diogo Biazus
Date:
Hi everybody,

I have some questions about the results in explain.
I don't know exactly what's the diference between "merge join" and "hash
join", wich one is faster?
What is the meaning of the cost number?
Is there any documentation about this?

Thanks in advance,

--
Diogo de Oliveira Biazus
diogo@ikono.com.br
Ikono Sistemas e Automação
http://www.ikono.com.br



Re: Is there any documentation on explain?

From
Bruce Momjian
Date:
See the existing docs on EXPLAIN, and papers on the developers site:

    http://developer.postgresql.org/index.php

---------------------------------------------------------------------------

Diogo Biazus wrote:
> Hi everybody,
>
> I have some questions about the results in explain.
> I don't know exactly what's the diference between "merge join" and "hash
> join", wich one is faster?
> What is the meaning of the cost number?
> Is there any documentation about this?
>
> Thanks in advance,
>
> --
> Diogo de Oliveira Biazus
> diogo@ikono.com.br
> Ikono Sistemas e Automa??o
> http://www.ikono.com.br
>
>
>
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