On Thu, Aug 21, 2025 at 5:28 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > Hmm. Up to now, we have not had an assumption that postmaster > children are aware of every other postmaster child. In particular, > not all postmaster children have PGPROC entries. How much does > this matter? What happens if the shared PGPROC array is corrupt?
It's also how we set latches, but yeah it's certainly an issue. Other ideas: 1. My other patch that used O_ASYNC (= ask the kernel to send SIGIO when the pipe becomes readable) worked, but required a pipe or socket pair per backend and is not actually in any standard. I think it is available almost everywhere anyway. I could rejuvenate that just to try out again. 2. I wonder if we could make better use of session IDs. I understand that we use them to signal eg archiver + its children, but I wonder if we could use a different granularity. postmaster's sid for most stuff, and per-backend sids when really needed, and then you just have to signal a small number of sessions, perhaps more than one but not much more. We pretend that setsid is optional but it's old POSIX and everywhere. I also know that Windows has a similar thing, I just haven't looked into it. > > Most of the patch is just removing hundreds of lines of errors and > > conditions and comments that were now unreachable. > > The patch would likely be a lot more readable if you split out the > "delete unreachable code" part into a separate step. Will do.
