[gwbas1c]

Probably the hardest thing to clean up is a codebase where very complicated "optimizations" were built because someone didn't understand some very basic bottlenecks.

I recently inherited an app that makes heavy use of Redis caching because someone didn't first try to optimizing SQL. The complexity that Redis caching adds is insane to maintain compared to spending a few minutes optimizing SQL.

The original poster really needs to hook up a profiler.

Also: having written lots of parallel code: Parallelization isn't a magic way to make things faster. If the codebase is breaking up tasks into lots of tiny tasks that run in parallel, there might be more overhead in parallelization than needed. Sometimes the fastest (performance and implementation) way to parallelize is to keep most of the codebase serial, but only parallelize at the highest level and never share data among operations.

[tmnstr85]

The old... anything but reviewing the execution plan approach... throw more vCPU's at it! Thank god for query store.