Hi, On 2022-07-11 22:22:28 -0400, Melanie Plageman wrote: > Yes, per an off list suggestion by you, I have changed the tests to use a > sum of writes. I've also added a test for IOPATH_LOCAL and fixed some of > the missing calls to count IO Operations for IOPATH_LOCAL and > IOPATH_STRATEGY. > > I struggled to come up with a way to test writes for a particular > type of backend are counted correctly since a dirty buffer could be > written out by another type of backend before the target BackendType has > a chance to write it out.
I guess temp file writes would be reliably done by one backend... Don't have a good idea otherwise. > I also struggled to come up with a way to test IO operations for > background workers. I'm not sure of a way to deterministically have a > background worker do a particular kind of IO in a test scenario. I think it's perfectly fine to not test that - for it to be broken we'd have to somehow screw up setting the backend type. Everything else is the same as other types of backends anyway. If you *do* want to test it, you probably could use SET parallel_leader_participation = false; SET force_parallel_mode = 'regress'; SELECT something_triggering_io; > I'm not sure how to cause a strategy "extend" for testing. COPY into a table should work. But might be unattractive due to the size of of the COPY ringbuffer. > > Would be nice to have something testing that the ringbuffer stats stuff > > does something sensible - that feels not entirely trivial. > > > > > I've added a test to test that reused strategy buffers are counted as > allocs. I would like to add a test which checks that if a buffer in the > ring is pinned and thus not reused, that it is not counted as a strategy > alloc, but I found it challenging without a way to pause vacuuming, pin > a buffer, then resume vacuuming. Yea, that's probably too hard to make reliable to be worth it. Greetings, Andres Freund
