Re: Add callbacks for fixed-numbered stats flush in pgstats

On Wed, Sep 04, 2024 at 06:27:43AM +0000, Bertrand Drouvot wrote:
> Agree. The idea was to add an additional parameter (say "check_only") to the
> flush_fixed_cb. If this parameter is set to true then the flush_fixed_cb would
> do nothing (no flush at all) but return a boolean that would indicate if there
> is pending stats. In case it returns false, then we could avoid the clock check.

Hmm. It's the same thing in terms of logic, but I am not really
convinced that it is a good idea to mix a code path for a sanity check
with a code path dealing with the action, particularly considering
that there is the nowait option to think about in the flush callback
which would require one to think about 4 possible states rather than
two possibilities. So that's more error-prone for extension
developers, IMO.

At the end, I have used my original suggestions for the callbacks. If
there are voices in favor of something different, we still have a good
chunk of the development and beta cycle for that.
--
Michael