From: Sergei Golubchik
Date: December 5 2003 10:37pm
Subject: Re: fulltext search speed issue with SQL_CALC_FOUND_ROWS
List-Archive: http://lists.mysql.com/mysql/155171
Message-Id: <20031205223702.GE65646@serg.mylan>
MIME-Version: 1.0
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Hi!

On Dec 05, tk wrote:
> Hello Sergei, Gunnar, and others,
> 
> thank you for your quick responses.
> One little mystery remains:
> 
> Why does one need to read all the row data (with
> SQL_CALC_FOUND_ROWS) to get the total number of
> results when using a limit? 
> 
> When the index is used to find relevant rows and sort
> the results, the code certainly must know how many
> total results there are. 

Yes, but it's different code, it works on a different level and knows
nothing about SQL_CALC_FOUND_ROWS :(
 
> Could one not store the total while using the index
> and use "select FOUND_ROWS()" without
> SQL_CALC_FOUND_ROWS to retrieve the total?

Yes, it could.
It is the optimization that wasn't implemented yet.
(but it's in the TODO)

Regards,
Sergei

-- 
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  /  |/  /_ __/ __/ __ \/ /   Sergei Golubchik <serg@stripped>
 / /|_/ / // /\ \/ /_/ / /__  MySQL AB, Senior Software Developer
/_/  /_/\_, /___/\___\_\___/  Osnabrueck, Germany
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