Re: BUG #16927: Postgres can`t access WAL files

Yes, for this moment I have 4 clusters on developer server and 1 cluster
that I`m testing by my own and there is no error connected with
access to WAL files for last about 17-20 hours. I`ll will run my prod
clusters and will also tell you. If I won`t send you any new message - the
problem is gone also on prod server. Thanks in advance!
P.S: the error "2021-03-18 12:22:26.096 EET [4840] LOG:  could not rename
temporary statistics file "pg_stat_tmp/global.tmp" to
"pg_stat_tmp/global.stat": Permission denied" still be, as I know it`s not
very
P.S.S: will be this patch available to download for everyone?

чт, 18 мар. 2021 г. в 23:56, Michael Paquier <michael@paquier.xyz>:

> On Thu, Mar 18, 2021 at 02:16:21PM +0200, Ярослав Пашинский wrote:
> > чт, 18 мар. 2021 г. в 13:15, Michael Paquier <michael@paquier.xyz>:
> >> On Thu, Mar 18, 2021 at 12:44:29PM +0200, Ярослав Пашинский wrote:
> >>> So, I started test on my Windows server that we using for replica on
> >>> instance, which I copied from master. The binarys was unpatched, that
> >>> you sent me here. The system is: windows server 2016, os build
> 14393.4283.
> >>> To emulate load I used pgbench with such parameters -t 10000 -c 50 -j
> 20.
> >>> After couple of running test in log file I found almost same errors:
> >>> "2021-03-18 11:27:14.322 EET [3748] LOG:  could not rename temporary
> >>> statistics file "pg_stat_tmp/global.tmp" to "pg_stat_tmp/global.stat":
> >>> Permission denied
> >>> 2021-03-18 11:27:18.928 EET [692] LOG:  using stale statistics instead
> of
> >>> current ones because stats collector is not responding"
> >>> ...and
> >>> "2021-03-18 11:48:49.630 EET [6476] LOG:  could not rename file
> >>> "pg_wal/00000001000000650000008F": Permission denied"
> >>> So I decided to switch to patched binaries and sometimes get only this
> >>> one error:
> >>> "2021-03-18 12:27:14.571 EET [4840] LOG:  could not rename temporary
> >>> statistics file "pg_stat_tmp/global.tmp" to "pg_stat_tmp/global.stat":
> >>> Permission denied
> >>> 2021-03-18 12:27:19.178 EET [7556] LOG:  using stale statistics instead
> >> of current ones because stats collector is not responding"
> >>> Which is not very critical, so it`s ok.
> >>
> >> Okay, so it looks like a very good news to me.  With the patched
> >> binaries you are not seeing the renaming problem with the WAL files
> >> anymore.
> >>
> >>> On other hand, on developer server (Windows Server 2016 (version 1607,
> OS
> >>> build 14393.4225))  with real load and unpatched binaries now I got no
> >>> errors about about pg_wal and gets only twice this error:
> >>> "2021-03-18 12:07:26.153 EET [2956] LOG:  could not rename temporary
> >>> statistics file "pg_stat_tmp/global.tmp" to "pg_stat_tmp/global.stat":
> >>> Permission denied"
> >>>
> >>> So, keep testing. That's strange for now. I am thinking about changing
> >>> binaries on prod server, but it will be possible on Saturday.
> >>
> >> Yes, I think that it would be good to do more tests, as it may be
> >> possible that what you are seeing does not repeat.  What you are
> >> reporting is encouraging though.  Thanks!
> >>
> >> By the way, it is very important to report that to the community
> >> mailing lists.  Could you add pgsql-bugs when replying please?
> >
> > The strange thing is why one server works fine on unpatched binaries
> while
> > the second one requires a patched version to get rid of pg_wal access
> > error.
> >
> > UPD: just right now on developer server I got an error: "2021-03-18
> > 14:11:39.444 EET [892] LOG:  could not rename file
> > "pg_wal/00000001000009130000006F": Permission denied"
> > Will switch to patched binaries and tell you later.
>
> The issue seems to depend on timing and the load your cluster is
> facing, so that is not surprising to hear that this does not show up
> 100% of the time.  I am actually glad to hear that you have not seen
> the issue anymore with the patched builds, while the unpatched builds
> have shown the problem at least once.  It would be a problem if the
> patched builds begin to complain about the renaming of the WAL
> segments though as we would have to consider a different theory.
>
> > P.S: Sorry, that I didn't include in reply psql-bugs, is it ok right now?
>
> That's fine.  Thanks :)
>
> I have added to this email the last things we discussed, for
> transparency.
> --
> Michael
>