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From:Thimble Smith Date:February 21 2001 2:38pm
Subject:Re: Optimisation suggestion...
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On Wed, Feb 21, 2001 at 12:59:43PM +0000, Antony T Curtis wrote:
> In the case where there is a SELECT on a table where no index is
> directly applicable, if there is a compound index where the second part
> (or third, etc) of the index is used in the WHERE clause, it should be
> possible to still use that index by being able to skip rows rather than
> doing a brute-force search through all the records.
> 
> Any hints where I should look to see if such an optimisation could be
> implemented?

It isn't clear to me how that would work.  Do you mean, to scan
the whole index in order to find rows where the secondary index
part matches, instead of scanning the data file?  Or do you have
something else in mind?  I think this optimization wouldn't work,
but I'm not sure I understand what you're suggesting.

Tim

-- 
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  /  |/  /_ __/ __/ __ \/ /    Tim Smith <tim@stripped>
 / /|_/ / // /\ \/ /_/ / /__   MySQL AB, Development Team
/_/  /_/\_, /___/\___\_\___/   Boone, NC  USA
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Thread
character set conf fileChi-Wai Lau21 Feb
  • character set conf fileMichael Widenius21 Feb
  • Optimisation suggestion...Antony T Curtis21 Feb
    • Re: Optimisation suggestion...Thimble Smith21 Feb
  • Re: Optimisation suggestion...Antony T Curtis21 Feb
    • Re: Optimisation suggestion...Michael Widenius5 Mar
  • Re: Optimisation suggestion...Antony T Curtis5 Mar
    • Re: Optimisation suggestion...Michael Widenius5 Mar
  • Re: Optimisation suggestion...Antony T Curtis6 Mar
RE: Optimisation suggestion...Enrique Villar6 Mar
  • Re: Optimisation suggestion...Antony T Curtis6 Mar