Re: nuderstanding 'explain analyse' - Mailing list pgsql-performance

From Josh Berkus
Subject Re: nuderstanding 'explain analyse'
Date
Msg-id 200411162207.50341.josh@agliodbs.com
Whole thread Raw
In response to nuderstanding 'explain analyse'  (Alexandre Leclerc <alexandre.leclerc@gmail.com>)
List pgsql-performance
Alexandre,

> If the plans for both queries are exactly the same, should I assume
> that the cost will also be the same?

Nope.   A seq scan over 1,000,000,000 rows is going to cost a LOT more than a
seq scan over 1000 rows, even though it's the same plan.

When you have the data sorted out, post explain analyzes and we'll take a shot
at it.

--
Josh Berkus
Aglio Database Solutions
San Francisco

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