This is what Jonny Harris, core development contributor, says: In WordPress 6.1, there is a massive improvement to database performance. Database queries in WP_Query are now cached. A ticket I have been working on for 5+ years was merged. This should result in billions of less repeated database queries".
Asked if this wasn't an improvement that was already in version 6.0, Harris replied: "We are improve database performance all the time. There was improved to term query caching in 6.0. This is post query caching. Related but not the same. That issue was patched in 6.0.1. I patched it myself".
Although there is no documentation on this particular enhancement yet, I expect to hear more about it in a few days.
WordPress 6.1 will be released on 1 November and will be the third major update of 2022 on its way to the FSE (full site editing as a native option).
Beta 3 will be available for installation and testing today, and three release candidates will be available for testing between 11 and 25 October, depending on their development cycle
Yesterday I installed beta 2 in the test environment with the intention of trying out the new features, but mainly because of the much-lauded performance improvement in query caching, which is what I'm most interested in, and to be able to measure the differences in loading speed.
With this new database caching feature, instead of making a direct query to the database, WP will first check if what is requested is cached and extract the information from there with the consequent saving of queries, which for large databases (like the one of this blog) with a high volume of posts, can be a significant drag on performance.
Remember that if you are encouraged to test any development version of WordPress, you should always do so in a staging environment, never on a production site. To do this you can use the WordPress Beta Tester plugin and uninstall it once you have finished your caching.
While I test the thing, I leave here these fireworks that I got the other day because they probably won't be repeated very often, at least not for all pages.