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Bug 123092 - postgres user not created due to nscd delay
Summary: postgres user not created due to nscd delay
Keywords:
Status: CLOSED DUPLICATE of bug 125421
Alias: None
Product: Fedora
Classification: Fedora
Component: postgresql
Version: rawhide
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Tom Lane
QA Contact: David Lawrence
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2004-05-12 11:35 UTC by Dams
Modified: 2013-07-03 03:01 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2006-02-21 19:03:12 UTC
Type: ---
Embargoed:

Attachments (Terms of Use)

Description Dams 2004-05-12 11:35:06 UTC 
Description of problem:
It seems the user postgres is not created when installing postgresql*
packages. 

[root@gruyere /var]# rpm -q postgresql-libs postgresql
postgresql-libs-7.4.2-1
postgresql-7.4.2-1
[root@gruyere /var]# apt-get install postgresql-server
Reading Package Lists... Done
Building Dependency Tree... Done
The following NEW packages will be installed:
   postgresql-server (7.4.2-1)
0 upgraded, 1 newly installed, 0 removed and 0 not upgraded.
Need to get 0B/3098kB of archives.
After unpacking 7591kB of additional disk space will be used.
Checking GPG signatures...
Committing changes...
Preparing...               
########################################### [100%]
chown: `postgres:postgres': invalid user
   1:postgresql-server     
########################################### [100%]
warning: user postgres does not exist - using root
warning: user postgres does not exist - using root
warning: user postgres does not exist - using root
warning: user postgres does not exist - using root
Done.

Version-Release number of selected component: postgresql-7.4.2-1
Comment 1 Tom Lane 2004-05-12 14:42:08 UTC 
Hm, there is code in the server RPM specfile to create user postgres
and group postgres if they do not already exist.  Can you try these
commands by hand (as root) and see what happens?

groupadd -g 26 -o -r postgres

useradd -M -n -g postgres -o -r -d /var/lib/pgsql -s /bin/bash \
	-c "PostgreSQL Server" -u 26 postgres

The specfile is set up to ignore any and all errors from these
commands, which I suppose is meant to avoid failing if the user/group
already exist, but I suspect it is masking some other problem that's
specific to your installation.
Comment 2 Dams 2004-05-12 16:03:53 UTC 
[root@gruyere /var]# groupadd -g 26 -o -r postgres
groupadd: group postgres exists
zsh: exit 9     groupadd -g 26 -o -r postgres
[root@gruyere /var]# useradd -M -n -g postgres -o -r -d /var/lib/pgsql
-s /bin/bash -c "PostgreSQL Server" -u 26 postgres
[root@gruyere /var]#

Group has been added by the package, the user hasnt. (note that rpm
doesnt complain about the group)
I can reproduce the problem with "rpm -e postgresql-server ; rpm -Uvh
postgresql-server-7.4.2-1".

After a little more investigation : the problem is not in postgresql,
it's nscd. If i shutdown it, the problem is fixed. I think we can
close as WORKSFORME.. or reassign it to the glibc.
Comment 3 Tom Lane 2004-05-12 17:40:06 UTC 
Hmm ... [reads nscd man page] ...  So the real issue is that the
groupadd/useradd sequence is done by the script fast enough that the
group name is not visible through the nscd cache at the time useradd
runs, causing useradd to fail.  Even if useradd were to be hacked to
succeed, the subsequent chown would probably come along before nscd
times out and updates its cache.

One would think this happens for every RPM that tries to create a new
user/group, not just Postgres.

The only Postgres-level solution I can see is to put a couple of
"sleep 15" delays into the RPM's preinstall script, which I'm not
willing to do.  My thought is that nscd is fundamentally broken if it
doesn't watch for updates to the underlying files, rather than rely on
a timeout.

I'm gonna cc the nscd maintainer and see what he has to say.  (I'd
re-mark this as an nscd bug, except the popup list doesn't offer it as
an option.  Odd.)
Comment 4 Ville Skyttä 2004-06-06 19:12:16 UTC 
See bug 125421.
Comment 5 Tom Lane 2004-06-19 21:31:08 UTC 
I'm closing this bug entry, since bug 125421 against nscd seems to be
where the problem really is.

*** This bug has been marked as a duplicate of 125421 ***
Comment 6 Ville Skyttä 2004-06-19 22:05:56 UTC 
...against shadow-utils, that is :)
Comment 7 Red Hat Bugzilla 2006-02-21 19:03:12 UTC 
Changed to 'CLOSED' state since 'RESOLVED' has been deprecated.
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