I have been scratching my head about MySQL startup for some time. There is much to say about this, and many other posts will probably follow. For now, it is enough to know that with many tables (millions) the startup of MySQL 8.0+ (including 8.0, 8.4 and 9.0) is suboptimal (to say the least). With very little changes, I was able to speed it up, from 2:39 to 1:09 (one minute and nine seconds). This result is obtained with 1 million tables on a m6id.xlarge AWS instance (4 vcpu and local SSD). It does not translate directly to EBS volumes, even though there are still things I think can be done there. I describe all the details of my optimizations in the rest of this post.
