Nice slides (linked from the article).<p>Since I'm MySQL ignorant, you say:<p>"the code wasn't sure if a row would already exist in the table, so it would issue a DELETE just in case followed by an INSERT with the correct data"<p>I come from a batch oriented background, so whenever I read something like this, my 'use a merge statement' light goes on.<p>I have literally no clue about the locking behavior of such an approach in MySQL, so I'm curious if (a) it was an option at all and (b) what locking behavior MySQL would throw into play with a merge (upsert) directly.