Sarcasm aside, you clearly
don't understand what my problem is.
1. Recent Comments invalidates every page it appears on whenever a comment is posted in any thread. In practice that means that the entire site cache is invalid. That breaks whole-page caching models.
2. This means that Wordpress will regenerate from scratch.
3. This means first of all generating the page, which joins multiple tables including TEXT fields. Because of the brilliant design of MySQL, these joins ignore indices on the joining fields and frequently the join will occur on disk.
4. The Recent Comments plugin also causes joins on disk because it too refers to tables with TEXT fields.
5. The query cache helps a lot, but the site on Linode was still observably jammed on I/O, even when MySQL was given an entire server to itself.
However, if you feel you can do it better, I am happy to engage your services as a fulltime replacement. WPEngine said they could do it for $250/month (they couldn't). Pagely said they could do it for $149/month (they couldn't). I invite your bid.
1. Recent Comments invalidates every page it appears on whenever a comment is posted in any thread. In practice that means that the entire site cache is invalid. That breaks whole-page caching models.
2. This means that Wordpress will regenerate from scratch.
3. This means first of all generating the page, which joins multiple tables including TEXT fields. Because of the brilliant design of MySQL, these joins ignore indices on the joining fields and frequently the join will occur on disk.
4. The Recent Comments plugin also causes joins on disk because it too refers to tables with TEXT fields.
5. The query cache helps a lot, but the site on Linode was still observably jammed on I/O, even when MySQL was given an entire server to itself.
However, if you feel you can do it better, I am happy to engage your services as a fulltime replacement. WPEngine said they could do it for $250/month (they couldn't). Pagely said they could do it for $149/month (they couldn't). I invite your bid.