> ... that being said (and I took a quick test with 10000
> randomly-inserted
> records and fetched them in index order) if the data's in the
> cache, the
> speed difference is insignificant.
As long as everything fits into the system cache and is
already in there, this test is moot.
> I did this:
>
> create table foo (a int not null,b char(100));
> create index foo_a on foo(a);
> for(i=0; i<10000; i++) {
> insert into foo(a,b) values( `((i*3467)%10000)` , 'fusli');
> }
here you need to reboot the machine or make sure nothing is cached.
then time the following and make sure it uses the index afterwards.
> select a from foo order by a;
Andreas