Re: Why this index?

[Thimble Smith]

At 19:11, 19990722, Steven Roussey wrote:
>170 (63 with c=0) rows match 15950 and 19687 (3586 with c=0) rows match
>12750.
>
>With so many rows matching, it seems to me that it ought to use the 8 byte
>index(a,c) that matches the where clause rather than the first 4 bytes of
>the index(a,b).

I could be way off, but have you used isamchk -a to inform MySQL about
your tables?  It sometimes does real wonders for the proper selection
of keys to use.

Tim