"Jafri, Nazneen" <nazja...@amazon.com> writes:
> The default setting of parameter io_max_concurrency shows 64 whereas the
> documentation says -1, checking if this is the expected behavior.
I think it's behaving as designed: the bootstrap default is indeed -1, but
later in startup there is an an auto-tuning step that replaces that with
a number chosen as stated in the docs (which evidently comes out as 64
on your system).
There are other auto-tuned GUCs that behave similarly. We could leave the
user-exposed setting as "-1", but it was argued that that was unhelpful
compared to exposing the value chosen by auto-tuning.
regards, tom lane
