Re: Some other CLOBBER_CACHE_ALWAYS culprits

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> On 2021-May-14, Tom Lane wrote:
>> An idea I'd been toying with was to make invals probabilistic, that is
>> there would be X% chance of an inval being forced at any particular
>> opportunity.  Then you could dial X up or down to make a tradeoff
>> between speed and the extent of coverage you get from a single run.
>> (Over time, you could expect pretty complete coverage even with X
>> not very close to 1, I think.)

> Maybe we could say that debug_invalidate_system_caches_always=2 means to
> use the current behavior, and debug_invalidate_system_caches_always=1
> uses some probabilistic rule?

What I had in mind was to replace the boolean with an actual fraction.
Probability zero is the non-debug behavior, and probability one gives
you the same result as CLOBBER_CACHE_ALWAYS, and values in between
give you tradeoffs.  But I'm not sure exactly how to extend that to
the recursive cases.

            regards, tom lane