Bug 1480624

Summary: pg_upgrade from rh-postgresql95 fails against el7 postgresql (9.2)
Product: Red Hat Software Collections Reporter: Simone Tiraboschi <stirabos>
Component: postgresqlAssignee: Pavel Raiskup <praiskup>
Status: CLOSED NOTABUG QA Contact: qe-baseos-daemons
Severity: high Docs Contact:
Priority: unspecified    
Version: rh-postgresql95CC: databases-maint, didi, hhorak, pkubat, praiskup
Target Milestone: ---   
Target Release: 3.1   
Hardware: Unspecified   
OS: Unspecified   
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Last Closed: 2017-08-14 10:44:29 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Blocks: 1459134    

Description Simone Tiraboschi 2017-08-11 14:11:22 UTC 
Description of problem:
pg_upgrade from rh-postgresql95 fails against el7 postgresql (9.2) with

command: "/usr/bin/pg_ctl" -w -l "pg_upgrade_server.log" -D "/var/lib/pgsql/data" -o "-p 50432 -b  -c listen_addresses='' -c unix_socket_permissions=0700 -c unix_socket_directory='/tmp'" start >> "pg_upgrade_server.log" 2>&1
waiting for server to start....FATAL: unrecognized configuration parameter "unix_socket_directory" .... stopped waiting pg_ctl: could not start server

The root cause is that the configuration parameter unix_socket_directory has been replaced by unix_socket_directories (plural!!!) with upstream postgres 9.3 (see: https://www.postgresql.org/docs/current/static/release-9-3.html#AEN114343 )

But Fedora maintainers backported that change to 9.1 and 9.2, see:
https://bugzilla.redhat.com/show_bug.cgi?id=853353
https://bugzilla.redhat.com/show_bug.cgi?id=825448

Now pg_upgrade checks the source PostgreSQL version in order to get the right list of options for it. It uses unix_socket_directory if source is < 9.3, unix_socket_directories otherwise.
See https://github.com/postgres/postgres/blob/837255cc81fb59b12f5a70ac2a8a9850bccf13e0/src/bin/pg_upgrade/server.c#L213

The problem is that now, due to the back-porting of that change at F17 time, pc_ctl on postgresql 9.2 shipped with el7 expects unix_socket_directories as it's 9.3 and so it fails when run by pg_upgrade (which ignores the back-port of the 9.3 parameter at F17 time).

Version-Release number of selected component (if applicable):
rh-postgresql95.x86_64             2.2-2.el7

How reproducible:
100%

Steps to Reproduce:
1. run pg_upgrade
2.
3.

Actual results:
command: "/usr/bin/pg_ctl" -w -l "pg_upgrade_server.log" -D "/var/lib/pgsql/data" -o "-p 50432 -b  -c listen_addresses='' -c unix_socket_permissions=0700 -c unix_socket_directory='/tmp'" start >> "pg_upgrade_server.log" 2>&1
waiting for server to start....FATAL: unrecognized configuration parameter "unix_socket_directory" .... stopped waiting pg_ctl: could not start server


Expected results:
It successfully executes 

Additional info:
Maybe it's worth to be fixed in Fedora PostgreSQL

[root@centos73e ~]# postgres --version
postgres (PostgreSQL) 9.2.18
[root@centos73e ~]# postgres --describe-config | grep -o 'unix_socket_director\w*'
unix_socket_directories
[root@centos73e ~]# yum list installed | grep postgresql-server
postgresql-server.x86_64           9.2.18-1.el7         @base                   
rh-postgresql95-postgresql-server.x86_64
Comment 3 Pavel Raiskup 2017-08-14 10:44:29 UTC 
(In reply to Simone Tiraboschi from comment #0)
> The problem is that now, due to the back-porting of that change at F17 time,
> pc_ctl on postgresql 9.2 shipped with el7 expects unix_socket_directories as
> it's 9.3 and so it fails when run by pg_upgrade (which ignores the back-port
> of the 9.3 parameter at F17 time).

That's known problem;  but since RHEL7 PostgreSQL 9.2 behaves differently from
upstream postgresql, pg_upgrade from rhscl doesn't know whether it is performing
upgrade *from* data generated by upstream postgresql server or *from* datadir
generated by RHEL7 "downstream patched" server.

That's why there's (temporary, for RHEL7 time-being) environment variable
REDHAT_PGUPGRADE_FROM_RHEL.  Set that variable to '1' and pg_upgrade should
behave correctly (ie. it should use unix_socket_directories even for 9.2
server).

Other option (and it is preferred!) is to (a) backup first and (b) use the
'postgresql-setup --upgrade' command wrapper (instead of using pg_upgrade
directly).  This way you save a lot of headaches with permissions, enabling
collections, environment variables, etc.