wp-includes/comment.php line85 causes slow query due to the non-indexed column

[matsubobo]

Following query is causes slow query if the wp_comment table is huge.

$ok_to_comment = $wpdb->get_var("SELECT comment_approved FROM $wpdb->comments WHERE comment_author = '$author' AND comment_author_email = '$email' and comment_approved = '1' LIMIT 1");                                                         

In my case, I have 600 thousand records in the wp_comments table and the query takes over 10 minutes to complete.

​http://matsu.teraren.com/blog/wp-content/uploads/2012/08/a40b1291fd99413dc3057fbe0b792a93.png

To fix this issue, I added index on my running wordpress and returns 0.00sec.

I'll attach the patch for create table file.

patch for create table.