“Copying to tmp table” extremely slow

You may need to try setting certain variables within your session

• tmp_table_size
• max_heap_table_size

These particular values may be too small for your DB Connection to fulfill the query efficiently. These can be set within as follows:

To see what values these settings have currently do the following:

• SHOW VARIABLES LIKE 'max_heap_table_size';
• SHOW VARIABLES LIKE 'tmp_table_size';

To set max_heap_table_size to 64M do the following:

• SET max_heap_table_size = 1024 * 1024 * 64;

To set tmp_table_size to 32M do the following:

• SET tmp_table_size = 1024 * 1024 * 32;

If you cannot set these values within your own session, contact your hosting provider to dynamically set them in your my.cnf.

Give it a Try !!!