From: Craig Ringer [mailto:craig@2ndquadrant.com] > TL;DR: Lets add a ProcSignalReason that makes a backend call > MemoryContextStats when it sees it and a C func that users can use to set > it on a proc. Sane?
> So how about borrowing a ProcSignalReason entry for "dump a memory context > summary at your earliest convenience" ? We could name it a more generic > "dump debug data" in case we want to add things later. > > Then a new pg_log_debug_backend(int) function or something like that could > signal the proc and let CHECK_FOR_INTERRUPTS handle calling > MemoryContextStats next time it's called.
+1 That's one of things I wanted to do. It will be more useful on Windows. Would it work for autovac processes and background workers, etc. that connect to shared memory?
Anything that uses CHECK_FOR_INTERRUPTS() and is attached to PGXACT. So yeah, pretty much anything attached to shmem.
I have also wanted to dump stack traces. Linux (glibc) has backtrace_symbols(), and Windows has StackWalk()/StackWalk64(). Is it sane to make the function a hook?
In-proc stack traces are immensely useful, and IMO relatively safe in a proc that's already in a reasonable state. If your stack is mangled, making it worse with an in-proc stack trace is rarely your biggest concern. I'd LOVE to be able to do this.
However, I'd want to address anything like that quite separately to the change I proposed to expose an existing facility.