Need helping creating indexes to join 10 million+ table with others quickly

[xvszero]

My experience with indexes is usually do this...

create index indexnamehere on tablenamehere(columnnamehere)

on the fields I am joining to other tables and voila, everything works fine.

But now I have to do a join between a table with a 10 million+ records and another with about 250k. And they have to be joined on two different columns, which combine to create one "unique" identifier. I set up the indexes the way I usually do, but when I actually try to do the selection everything just stalls up.

Any ideas?

[chazzy]

try doing an explain on the query you're using first, see if it's actually using your new index or not.

[xvszero]

What's an explain?!

Also, how fast can I reasonably expect this stuff to work anyhow? I'm used to getting responses in mere seconds, but then again I've never had a 10 million row table before.

[chazzy]

what dbms?