On Tue, Nov 07, 2023 at 11:47:46AM -0500, Stephen Frost wrote: > We only care about the value of the unlogged LSN being correct during > normal shutdown when we're writing out the shutdown checkpoint, but by > that time everything else has been shut down and the value absolutely > should not be changing.
I agree that's all true. I'm trying to connect how this scenario ensures we see the most up-to-date value in light of this comment above pg_atomic_read_u32(): * The read is guaranteed to return a value as it has been written by this or * another process at some point in the past. There's however no cache * coherency interaction guaranteeing the value hasn't since been written to * again. Is there something special about all other backends being shut down that ensures this returns the most up-to-date value and not something from "some point in the past" as the stated contract for this function seems to suggest? -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
