My db issues for last ten years have frequently been a mix of bad query plans and terrible orm layers. Doctrine in Symfony rarely yield good queries in mysql for us. We've been moving away from orm where possible because we don't need to support multiple databases. Further if I switch my db to postgres I'm changing out everything else anyway to remove php from the codebase. I didn't write the original code but my team has to maintain it. The orm makes that hard actually compared to staight sql in the end.