How to tell MySQL to ignore all indexes for a given query? I've been benchmarking several queries and learning about indexes by using the explain function, profiling and the SQL_NO_CACHE option. 

My usual benchmarking session goes something like this:

SET PROFILING=1;
SELECT SQL_NO_CACHE field_a, field_b FROM table WHERE xxx;
SHOW PROFILES;


Some times after adding indexes, I want to know how the query would perform without any index optimization; so my options so far are to either delete the related indexes or use explain to check what indexes are in use and hint MySQL what indexes to ignore;

EXPLAIN SELECT SQL_NO_CACHE field_a, field_b FROM table WHERE xxx;
SELECT SQL_NO_CACHE IGNORE INDEX (field_a) field_a, field_b FROM table WHERE xxx;
SHOW PROFILES;


Is there a similar option to tell MySQL not to use any index so I can get the query duration without any index optimization. Something like this:

SELECT SQL_NO_CACHE SQL_NO_INDEXES field_a, field_b FROM table WHERE xxx;
After a table name add USE INDEX() without arguments. That will make MySQL to ignore all index in the table.

Example:

SELECT SQL_NO_CACHE field_a, field_b FROM table USE INDEX() WHERE xxx;


Sorry for my english.