[Pkg-postgresql-public] PostgreSQL packages in Debian, problems on startup

[deavid]

Hi Christoph,

I'm glad to see that most of them are fixed and the rest seem to be fixed
soon. For me isn't a problem anymore as I now know how to repair these
things. But I feel other people will have a headache with these things, in
special when dealing with Log Shipping / Hot standby setups.

> both the unknown options and the systemd integration with
> pg_upgradecluster have been fixed in the meantime; unfortunately not
> in the jessie version of postgresql-common. Though if you say
> 9.5, is that from apt.postgresql.org? If so, make sure to upgrade to
> the postgresql-common version from there as well.

Yes, most probably is from apt.postgresql.org. It is my preferred source
for postgresql packages for my servers since a year ago.
This server was installed 4 months ago, and probably not upgraded since
then. I'll do ASAP.

> This has also been, well, addressed. It's not really fixable, see
> /lib/systemd/system/postgresql\@.service because of the way how
> instanced systemd service units work. pg_createcluster will now warn
> if you create a cluster with a dash in the name.

At least it prints a warning. Some people will not notice the text,
this has happened to me several times. But as you said, is not
fixable. I knew.

> If you change start.conf, you need to "systemctl daemon-reload" to get
> the generator symlinks updated.

In 9.5 start.conf doesn't say anything about this. But I've checked my 9.6
and it has the advise. So this was also fixed.
I didn't see this because I was still working with 9.5, and even in my
office computer which runs debian testing I already have 9.6, i didn't have
time yet to upgrade.

Anyway, thanks again for your work. I really appreciate it.





El jue., 6 oct. 2016 a las 20:11, Christoph Berg (<myon at debian.org>)
escribió:

> Package: postgresql-common
>
> Re: deavid 2016-10-05 <CAFR-75vif=
> hSH5E3f2SQSXV39vkNjcZVk+KQ3ya2UN6P25RziQ at mail.gmail.com>
> > Hello Cristoph,
> >
> > First of all, thank you a lot for your hard work on your tools for
> > postgresql clusters. It is very helpful indeed. PostgreSQL is a lot
> easier
> > to work with in Debian & Ubuntu thanks to those tools.
> >
> > I want to inform you about an issue, maybe because several bugs or misuse
> > for my part. I don't know.
> >
> > The issue itself can be explained as: init.d scripts manage a list of
> > servers/clusters different than the one in pg_lscluster.
> >
> > The effect is always the same, I end with some special cluster which
> > doesn't start or stop when called from /etc/init.d/postgresql start/stop.
> > When I try to manually start it, it does without problems.
> >
> > I had several talks in IRC on #postgres channel of Freenode, also i asked
> > on #debian and #debian-next and no one had a clue.
> >
> > Finally I traced the problem. And it seems to be a lack of documentation,
> > and maybe some bugs. I could trace it thanks to your documentation in
> > README files of postgresql-common package, but I think it could be better
> > explained.
> >
> > The problem lies in that init.d files rely on systemctl, which I don't
> know
> > how it works. Seems the second list is in
> > /var/run/systemd/generator/postgresql.service.wants/
> >
> > I would recommend to add a tool to check this folder and do some repair,
> > and output a log of possible problems.
> >
> > I've found 3 ways to get a broken list in systemd:
> >
> > 1) Failed pg_upgradecluster due to failure on postgresql.conf migration:
> > From 9.3 to 9.5 several options have changed and older options are no
> > longer supported. If you have modified those options then they are
> > uncommented. Most notable is checkpoint_segments, which the default is
> too
> > low, and disappears in newer versions. When the script tries to finally
> > "start" the cluster, it fails, and forgots to update systemd services; so
> > when you manually fix postgresql.conf there's no way to "resume" the
> > upgrade.
>
> > On the pg_upgradecluster failure, is an old problem now. I believe it was
> > wheezy, so it should be version 134wheezy4 or similar.
> > For the other two, they ocurred this week on an updated Jessie system, so
> > they should be version 165+deb8u1
>
> Hi deavid,
>
> both the unknown options and the systemd integration with
> pg_upgradecluster have been fixed in the meantime; unfortunately not
> in the jessie version of postgresql-common. Though if you say
> 9.5, is that from apt.postgresql.org? If so, make sure to upgrade to
> the postgresql-common version from there as well.
>
> > 2) Placing a dash (-) in the cluster name. Seems its a separator for your
> > scripts. When you do this, pg_createcluster doesn't notice and continues,
> > leaving you with a working cluster that doesn't start on boot.
>
> This has also been, well, addressed. It's not really fixable, see
> /lib/systemd/system/postgresql\@.service because of the way how
> instanced systemd service units work. pg_createcluster will now warn
> if you create a cluster with a dash in the name.
>
> > 3) Using pg_renamecluster. It leaves old names in systemd.
>
> That item is still open, thanks for spotting.
>
> > I would recommend:
> > * Add --skip-systemctl-redirect to the man page of pg_ctlcluster. It is
> > useful for debug problems. I had to drill down through the perl scripts
> to
> > find the option. (I do not know perl)
>
> Aye.
>
> > * Document in pg_ctlcluster how to fix if one cluster doesn't start on
> boot.
>
> Possibly, will think about it.
>
> > What I did manually to fix this:
> > * Modified the names of symlinks in
> > /var/run/systemd/generator/postgresql.service.wants/
>
> "systemctl daemon-reload" should have done that (that's what was
> missing in the old pg_upgradecluster version).
>
> > * systemctl daemon-reload
> > * systemctl stop postgresql
> > * pg_lsclusters to see if anyone is still runing, and stop it with
> > "pg_ctlcluster --skip-systemctl-redirect"
>
> That was the other half of the breakage; the cluster would not be
> started via systemd during the upgrade.
>
> > * systemctl start postgresql
> > * pg_lsclusters to see if every cluster is running again.
> >
> > I've checked a dozen times /etc/postgresql/9.5/*/start.conf ; but it has
> > its original contents. I tried "manual" and it doesn't help, so i put
> > "auto" again on it.
>
> If you change start.conf, you need to "systemctl daemon-reload" to get
> the generator symlinks updated.
>
> Christoph
>
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