In under 24 hours, I had a server crash twice. On the console I could see something about MySQL running out of memory, but other than that, I could not do much with the system other than pressing the reset-button. For some reason, the WordPress table “wp_postmeta” was about 46 megabytes (about 550,000 records), and trying to do something with that table resulted in timeouts etc. I could see the table contained a lot of records with meta_key = “_utw_tags_” and meta_key = “_utw_tags_0”. UTW is Ultimate Tag Warrior, but that’s a plugin active when I write a post, not when visitors access my blog.
So I performed the following command:
delete FROM `wp_postmeta` where `meta_key`= "_utw_tags_" or `meta_key`="_utw_tags_0"
That deleted about 540,000 records, and now the weblog is very responsive again, and the server is a lot less busy. That’s a good thing, right?