Posts Tagged ‘auto_increment’

Broken comments

h/t to Dave, the guy who contacted me and mentioned that he was unable to post comments on this blog; I didn’t realize the comments system was not functioning.

Now why the WordPress comment system would go down was a bit confusing and frustrating to diagnose. WP simply sent you to a blank page (wp-comments-post.php#comment-). After ruling out it was not an issue with the theme or a problem with a blank line in wp-comments-post.php (the first 2 cases mentioned here). I tried repairing the wp_comments table in the DB, which didn’t work (the post linked to mentions going further and wiping out the data and recreating the table, but I didn’t want to go that far). I ran across a few posts (such as this one) on the WP forums about similar issues, but nothing that led to a solution.

I decided to dig into wp-comments-post.php and started playing around with a few echo statements to see where things were going wrong. Turns out, wp_new_comment() was always returning a comment_id of 0. Not good. Assuming the WP code was correct (I had no reason to suspect otherwise), it had to be a problem with the database. The problem and solution turned out to be pretty trivial: the comment_ID field of the wp_comments table had the auto_increment attribute missing (which needs to be set; you can see the WP database scheme here). So all new comments were being assigned the default value of 0.

I’m not sure why this would happen; maybe an issue resulting from an upgrade my host did a while back or perhaps an issue with the WP auto-update process.