If you create a site from the 2.04 install and it only has the
PRIMARY and post_name indices/indexes in the posts table.
According to upgrade-schema.php, you are only suppose to have KEY and
post_name:
CREATE TABLE $wpdb->posts (
[A BUNCH OF FIELDS]
PRIMARY KEY (ID),
KEY post_name (post_name)
);
However, in upgrade-functions.php, the 'post_status' index is added as
part of function upgrade_101().
// Clean up indices, add a few
add_clean_index($wpdb->posts, 'post_name');
add_clean_index($wpdb->posts, 'post_status');
add_clean_index($wpdb->categories, 'category_nicename');
add_clean_index($wpdb->comments, 'comment_approved');
add_clean_index($wpdb->comments, 'comment_post_ID');
add_clean_index($wpdb->links , 'link_category');
add_clean_index($wpdb->links , 'link_visible');
It seems upgrade_101 is not called when a new DB is create because the
version is already 3440.
All of those other indices have been moved over to the schema file but
post_status has not.
