On Sun, Apr 05, 2020 at 07:56:51PM -0700, Andres Freund wrote:
> I found this while trying to benchmark the effect of my snapshot changes
> on 2pc. I just used the attached pgbench file.
>
> I've not yet reviewed the change sufficiently to pinpoint the issue.
Indeed. It takes seconds to show up.
> It's a bit sad that nobody has hit this in the last few months :(.
2PC shines with the code of xlogreader.c in this case because it keeps
opening and closing XLogReaderState for a short amount of time. So it
is not surprising to me to see this error only months after the fact
because recovery or pg_waldump just use one XLogReaderState. From
what I can see, the error is that the code only bothers closing
WALOpenSegment->seg when switching to a new segment, but we need also
to close it when finishing the business in XLogReaderFree().
I am adding an open item, and attached is a patch to take care of the
problem. Thoughts?
--
Michael
