Re: Planner not using column limit specified for one column for another column equal to first

From: Yeb Havinga <yebhavinga(at)gmail(dot)com>
To: Віталій Тимчишин <tivv00(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Planner not using column limit specified for one column for another column equal to first
Date: 2010-04-16 13:21:30
Message-ID: 4BC8645A.2060700@gmail.com
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Віталій Тимчишин wrote:
>
> BTW: Changing slow query to inner joins do not make it fast
I'm interested to see the query andplan of the slow query with inner joins.

>
>
> Another thing is it seems that the number of rows guessed is far
> off from the actual number of rows, is the number 5000000
> artificial or are you're statistics old or too small histogram/mcv's?
>
>
> Nope, I suppose this is because of limit. If I remove the limit, the
> estimations are quite correct. There are ~6 millions of row in each table.
Yes, that makes sense.

regards,
Yeb Havinga

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