Re: Let PostgreSQL's On Schedule checkpoint write buffer smooth spread cycle by tuning IsCheckpointOnSchedule?

In summary, the X^1.5 correction seems to work pretty well. It doesn't completely eliminate the problem, but it makes it a lot better.

I don't want to over-compensate for the full-page-write effect either, because there are also applications where that effect isn't so big. For example, an application that performs a lot of updates, but all the updates are on a small number of pages, so the full-page-write storm immediately after checkpoint doesn't last long. A worst case for this patch would be such an application - lots of updates on only a few pages - with a long checkpoint_timeoout but relatively small checkpoint_segments, so that checkpoints are always driven by checkpoint_segments. I'd like to see some benchmarking of that worst case before committing anything like this.