One day I suspect I'll have to learn hadoop and transfer all this data to a non-structured database, but I'm surprised to find the performance degrade so significantly in such a short period of time.

I have a mysql table with just under 6 million rows. I am doing a very simple query on this table, and believe I have all the correct indexes in place.

the query is

SELECT date, time FROM events WHERE venid='47975' AND date>='2009-07-11' ORDER BY date

the explain returns

id  select_type     table   type    possible_keys   key     key_len     ref     rows    Extra
1   SIMPLE  updateshows     range   date_idx    date_idx    7   NULL    648997  Using where

so i am using the correct index as far as I can tell, but this query is taking 11 seconds to run.

The database is MyISAM, and phpMyAdmin says the table is 1.0GiB.

Any ideas here?

Edited: The date_idx is indexes both the date and venid columns. Should those be two seperate indexes?

mysql performance indexing
Edit
Report