wxr importer: defer comment counts
|Reported by:||tellyworth||Owned by:|
Comment counts are calculated and recalculated every time a comment is inserted. That's inefficient when there are multiple comments per post.
The enclosed patch implements and uses a wp_defer_comment_counting() function. It's based on wp_defer_term_counting().
I also removed the comment_exists() check in the importer, since in practice it always returns false (the post_exists() check means we only attempt to import comments when the parent post is new, and hence has no comments).