On Fri, Oct 1, 2021 at 1:06 PM Jeff Holt <jeff.holt@xxxxxxxxxxxx> wrote: > Now looking closely at postgreSQL, I see an opportunity to more quickly implement Oracle's current feature list. > > I've come to this point because I see many roadblocks for users who want to see a detailed "receipt" for their response time. I have heard of method R. Offhand it seems roughly comparable to something like the Top-down Microarchitecture Analysis Method that low level systems programmers sometimes use, along with Intel's pmu-tools -- at least at a very high level. The point seems to be to provide a workflow that can plausibly zero in on low-level bottlenecks, by providing high level context. Many tricky real world problems are in some sense a high level problem that is disguised as a low level problem. And so all of the pieces need to be present on the board, so to speak. Does that sound accurate? One obvious issue with much of the Postgres instrumentation is that it makes it hard to see how things change over time. I think that that is often *way* more informative than static snapshots. I can see why you'd emphasize the need for PostgreSQL to more or less own the end to end experience for something like this. It doesn't necessarily follow that the underlying implementation cannot make use of infrastructure like eBPF, though. Fast user space probes provably have no overhead, and can be compiled-in by distros that can support it. There hasn't been a consistent effort to make that stuff available, but I doubt that that tells us much about what is possible. The probes that we have today are somewhat of a grab-bag, that aren't particularly useful -- so it's a chicken-and-egg thing. It would probably be helpful if you could describe what you feel is missing in more general terms -- while perhaps giving specific practical examples of specific scenarios that give us some sense of what the strengths of the model are. ISTM that it's not so much a lack of automation in PostgreSQL. It's more like a lack of a generalized model, which includes automation, but also some high level top-down theory. -- Peter Geoghegan
