How To Diagnose And Fix Incorrect Post Comment Counts In WordPress
Updated: September 16th, 2012
Introduction
If your WordPress comment counts got messed up, whether because of a plugin (I'm talking about you, DISQUS) or you messed with your database manually and did something wrong (yup, that's what I just did), fear not – I have a solution for you.
But first, a little background.
Comment Counts In WordPress
Here's how comment counts work in WP:
- Posts live in a table called wp_posts and each has an ID.
- Comments reside in a table called wp_comments, each referring to an ID in wp_posts.
- However, to make queries faster, the comment count is also cached in the wp_posts table, rather than getting calculated on every page load.
If this count ever gets out of sync with
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[MySQL] Deleting/Updating Rows Common To 2 Tables – Speed And Slave Lag Considerations
Introduction
A question I recently saw on Stack Overflow titled Faster way to delete matching [database] rows? prompted me to organize my thoughts and observations on the subject and quickly jot them down here.
Here is the brief description of the task: say, you have 2 MySQL tables a and b. The tables contain the same type of data, for example log entries. Now you want to delete all or a subset of the entries in table a that exist in table b.
Solutions Suggested By Others
DELETE FROM a WHERE EXISTS (SELECT b.id FROM b WHERE b.id = a.id); |
beer planet is a blog about technology, programming, computers, and geek life. It is run by Artem Russakovskii - a local San Francisco geek who is currently pursuing his own projects and regularly enjoys hacking Android, PHP, CSS, Javascript, AJAX, Perl, and regular expressions, working on Wordpress plugins and tools, tweaking MySQL queries and server settings, administering Linux machines, blogging, learning new things, and other geeky stuff.
