When running InnoDB you are able to dig into the engine internals, look at various gauges and counters, see past deadlocks and the list of all open transactions. This is in your reach with one simple command — SHOW ENGINE InnoDB STATUS . On most occasions it works beautifully. The problems appear when you have [...]
How expensive is a WHERE clause in MySQL?
October 31, 2008 By 16 Comments
This is a fun question I’ve been wanting to test for some time. How much overhead does a trivial WHERE clause add to a MySQL query? To find out, I set my InnoDB buffer pool to 256MB and created a table that’s large enough to test, but small enough to fit wholly in memory:
