Re: Postgres, fsync, and OSs (specifically linux)

On 2018-05-22 21:58:06 +0200, Dmitry Dolgov wrote:
> > On 22 May 2018 at 20:59, Andres Freund <andres@anarazel.de> wrote:
> > On 2018-05-22 20:54:46 +0200, Dmitry Dolgov wrote:
> > Huh? Checkpointer was in SendFsyncRequest()? Coudl you share the
> > backtrace?
> 
> Well, that's what I've got from gdb:

>     #3  0x000000000077ad08 in WaitLatchOrSocket
> (latch=latch@entry=0x0, wakeEvents=wakeEvents@entry=4, sock=8,
> timeout=timeout@entry=-1, wait_event_info=wait_event_info@entry=0) at
> latch.c:385
>     #4  0x00000000007152cb in SendFsyncRequest
> (request=request@entry=0x7ffe37529f40, fd=fd@entry=-1) at
> checkpointer.c:1345
>     #5  0x0000000000716223 in AbsorbAllFsyncRequests () at checkpointer.c:1207

Oh, I see. That makes sense. So it's possible to self-deadlock
here. Should be easy to fix...  Thanks for finding that one.


> Yes, this patch solves the problem, thanks.

Just avoids it, I'm afraid... It probably can't be hit easily, but the
issue is there...

- Andres