A newsletter about using napkin math and first-principle thinking to estimate systems performance -- fast, and without writing any code! However, on a good day posts will include code to test whether the napkin math lines up with reality. If it doesn't, it's the more cause for an interesting post.

What is the expected throughput of a single-threaded, in-memory data-store like Redis? -- Problem 4
Is fsyncs per seconds and transactions per second for MySQL always the same? -- Problem 10
What do you expect the response time for a query that visits 50 database pages with a 80% page cache hit rate to be? -- Problem 2

With the napkin math reference numbers in hand, pen, paper, and some reasonable assumptions (such as average log size or database record size) we should be able to arrive at an approximate answer. This talk is the best primer on the topic.