I'll have to be careful here as I've no experience either with your DB or Postgres, but comparing questDB with PG and using that to claim it's 100X faster may be technically true but a bit of a dirty trick. It's perhaps like comparing a lorry with an F1 car and being surprised at the winner.
I'm also a little surprised at the speedup using SIMD. If it's RAM constrained, and it clearly is because it scales with the number of memory channels, then I completely fail to understand how instructions - which are bloody fast to execute (SIMD or not) compared to slow RAM access - could benefit you. Both SIMD or not should be waiting on memory AFAICS. Except you clearly do get a big speedup, could anyone enlighten me on this?
I'm also a little surprised at the speedup using SIMD. If it's RAM constrained, and it clearly is because it scales with the number of memory channels, then I completely fail to understand how instructions - which are bloody fast to execute (SIMD or not) compared to slow RAM access - could benefit you. Both SIMD or not should be waiting on memory AFAICS. Except you clearly do get a big speedup, could anyone enlighten me on this?