When you insert data into a database and run COMMIT you expect things to be there: Atomically, Consistent, Isolated and Durable
, like Codd commanded us 40 years ago, but also quickly. There is a surprising amount of sophistication being poured into this, but since I do not want to shame MongoDB and Redis developers in this post, I am not going to talk about that much in this place.
We are instead trying to understand what our databases are doing all day, from the point of view of the storage stack.
That Brendan Gregg Graphics
Here is your performance tooling (sans EBPF) as shown by Brendan Gregg in various iterations. We are interested into the various blues in this graphic, VFS and downwards. The most detailed information of what goes on in the blue stack is given by blktrace. It’s an I/O request recorder.
Unfortunately, blktrace …
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