[foxhill]

whilst "free" in principle, there is obvious cost/risk in adopting features like those (CTE demat and llvm), if nothing else, in even trying them out.

testing the llvm-based optimiser (in postgres 11) showed little benefit, and in a few circumstances slowed things down. had i had more time to poke around, i'd have probably got it to a place where it represented an improvement, but, up until i left that role, it was a feature that remained switched off - postgres doesn't generally introduce features that represents "breaks" in code.

having not had _that_ much experience with MS-SQL, i'd still recommend the switch. looking through the things in postgres that i take for granted vs. what's in MS-SQL, i don't think i could cope with not having postgres :)