Michael Widenius wrote:
> Hartmut, what information are you missing ?
> The above is as quite good way to describe it without going to pseudo code.
> The only things I can see that could be added are:
> - Indexes are numbered from 1 uppwards, in the same order as given
> by SHOW CREATE TABLE or SHOW INDEX
> - The index map is a bitmap that shows which index we will use for
> checking if we can use an index to retrieve the rows with either the
> range or index_merge methods. Ie, the value 5 (= 1 + 4 ) would
> tell you that mysqld will try to use index 1 and 3 for this.
that is exactly what was missing: the explanation of "N"
in the "(index map: N)" part ... which lead to all the
guessing (both right and wrong) in this thread ...
Hartmut Holzgraefe, Principal Support Engineer
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