Hi, Bill Easton wrote:
> I think that MySQL is doing what would be expected, namely an index scan
> which reads entire index on IP and selects distinct values of IP.
What I expect it to do is to give me all the distinct values in that
row. It should be able to notice that there are only a few distinct
values in there, and a "select distinct" over an indexed column doesn`t
need to do a full scan.
An open-coded loop
> val = db.Do("select min(IP) from test")
> while (val) {
> process(val)
> val = db.Do("select min(IP) from test where IP > '$val'")
> }
runs almost instantly. MySQL should be able to do that optimization, it's
rather obvious (ten million rows, and IP has less than 100 different
values).
--
Matthias Urlichs | {M:U} IT Design @ m-u-it.de | [EMAIL PROTECTED]
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