Re: ORDER BY ... DESC LIMIT 1 optimization ?

[Michael Widenius]

Hi!

>>>>> "Timothy" == Timothy Smith <tim@stripped> writes:

Timothy> On 2001 Sep 06, Fournier Jocelyn [Presence-PC] <joc@stripped>
> wrote:
>> It doesn't change anything, the query is still slow.

Timothy> OK, I believe that the optimization is not being done because
Timothy> MySQL doesn't realize that the ORDER BY is on the second part
Timothy> of the same key that is used for the WHERE clause.

Timothy> This might not be easy to fix in a general way, but we will
Timothy> look into it.

Just a note about this; There is a chance that MySQL 4.0.2 will fix
that (I just pushed code that fixes some ORDER BY ... DESC
optimizations)


Regards,
Monty

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