Re: archive status ".ready" files may be created too early

On 8/25/21, 11:01 AM, "Fujii Masao" <masao.fujii@oss.nttdata.com> wrote:
> If LogwrtResult.Flush >= EndPos, which means that another process already
> has flushed the record concurrently and updated XLogCtl->LogwrtResult.Flush.
> This situation also means that that another process called
> NotifySegmentsReadyForArchive(LogwrtResult.Flush). Right?

If the segment boundary wasn't registered before the other process
called NotifySegmentsReadyForArchive(), then it couldn't have used the
boundary for deciding which .ready files to create.

> If this understanding is right, there seems no need to wake walwriter up here
> so that it can call NotifySegmentsReadyForArchive(LogwrtResult.Flush) gain.
> Thought?

We're actually discussing this right now in another thread [0].  I
think we might be able to get rid of that part if we move the boundary
registration to before we release the WAL insert lock(s).

Nathan

[0] https://postgr.es/m/DE60B9AA-9670-47DA-9678-6C79BCD884E3%40amazon.com