From: Yeb Havinga <yebhavinga@gmail.com>
To: Віталій Тимчишин <tivv00@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Planner not using column limit specified for one column for another column equal to first
Date: Fri, 16 Apr 2010 15:21:30 +0200
Message-ID: <4BC8645A.2060700@gmail.com> (raw)
In-Reply-To: <k2u331e40661004160549td6bf86d5pb6fde70e6d1ab5d@mail.gmail.com>
References: <m2y331e40661004160102tff445f9eg165a04efe3b409ed@mail.gmail.com>
<4BC8204A.7050904@gmail.com>
<k2u331e40661004160549td6bf86d5pb6fde70e6d1ab5d@mail.gmail.com>
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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To: pgsql-performance@postgresql.org
Cc: yebhavinga@gmail.com, tivv00@gmail.com
Subject: Re: Planner not using column limit specified for one column for another column equal to first
In-Reply-To: <4BC8645A.2060700@gmail.com>
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