Re: Real vs Int performance

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От Igor Neyman
Тема Re: Real vs Int performance
Дата
Msg-id F4C27E77F7A33E4CA98C19A9DC6722A2070C23A0@EXCHANGE.corp.perceptron.com
обсуждение исходный текст
Ответ на Re: Real vs Int performance  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-performance

> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> Sent: Wednesday, January 26, 2011 5:12 PM
> To: David Greco
> Cc: pgsql-performance@postgresql.org
> Subject: Re: Real vs Int performance
>
> David Greco <David_Greco@harte-hanks.com> writes:
> > Came across a problem I find perplexing. I recreated the
> dimensional
> > tables in Oracle and the fields that are integers in Oracle became
> > integers in Postgres. Was experiencing terrible performance
> during the
> > load and narrowed down to a particular dimensional lookup
> problem.
> .......................................
> .......................................
> .......................................
> .......................................
> In real life, this query is actually bound and parameterized,
>
> In that case, an EXPLAIN using literal constants is next door
> to useless in terms of telling you what will happen in real
> life.  You need to pay attention to exactly how the
> parameterization is done.  Again, I'm suspecting a wrong
> datatype indication.
>
>             regards, tom lane
>

To see what happens with parametrized query in "real life" you could try
"auto_explain" contrib module.

Regards,
Igor Neyman

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