Contrib RFC: Counters for Slow InnoDB Sync Reads

I just submitted a MySQL Contribution and I would like to gather feedback about it.  Depending on the received feedback, I might submit an updated contribution.  The contribution is Counters for Slow InnoDB Sync Reads, and its goal is to make MySQL easier to operate on “complex” IO subsystems (like network drives in the cloud).

The bug report / feature request Bug #117740 : Please consider adding Slow IO Counters contains all the details about the contribution and the problem this is solving, including what is a sync read.  If you prefer looking at a PR over a patch file, you can check the Contrib / RFC Fake PR : Bug #117740 - Counters for Slow InnoDB Sync Reads (and if you want to know what is a Fake PR, it is also detailed in there).  If you have thoughts or questions about this, feel free to comment below or in the Contrib Fake PR.

Thanks in advance for any feedback you might have : this will allow me to make the contribution and MySQL even better !

Faster MySQL Startup with Many Tables (1M+)

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 (1 minute and 9 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.

RFC: Database / Schema in the Slow Query Log File

A month ago, I announced that I am working on a MySQL Contribution to add database / schema in the slow query log file (bug report, LinkedIn, Twitter, Facebook, and MySQL Community Slack).  My contribution is ready, and before submitting it, I would like feedback, so I am writing this post as a Request for Comments (RFC).  If you are in a hurry, you can go directly to the RFC Fake PR.  But what is a Fake PR ?  It is part of my way of working on MySQL Contributions, which I describe below, and on which I would also welcome feedback.  Something else covered in this post are the design choices made for this contribution, and again, I would welcome your feedback on them (I can make adjustments before submitting my contribution).  In this post, I also explain why having the database / schema in the slow query log file is important.