On 1/1/19 1:42 AM, Andrew Gierth wrote:
"Andreas" == Andreas Karlsson <andr...@proxel.se> writes:
Andreas> I believe I have fixed these except for the comment on the
Andreas> conditions for when we inline.
Andreas> Andrew Gierth: Why did you chose to not inline on FOR UPDATE
Andreas> but inline volatile functions? I feel that this might be
Andreas> inconsistent since in both cases the query in the CTE can
Andreas> change behavior if the planner pushes a WHERE clause into the
Andreas> subquery, but maybe I am missing something.
I chose not to inline FOR UPDATE because it was an obvious compatibility
break, potentially changing the set of locked rows, and it was an easy
condition to test.
I did not test for volatile functions simply because this was a very
early stage of the project (which wasn't my project, I was just
assisting someone else). I left the comment "this likely needs some
additional checks" there for a reason.
Thanks, that makes sense! I will need to ponder some on if the behavior
change when predicates are pushed into a subquery with volatile
functions is ok. I am leaning towards no, because otherwise inlining
CTEs would affect more than query performance.
Andreas
