This fix applies to [[:OAR 2.5.2]] and [[:OAR 2.5.3]], and must be taken into account if upgrading to any later version of OAR (i.e. starting from [[:OAR 2.5.4]])

=== Description of the issue ===
With [[:OAR 2.5.2]] and [[:OAR 2.5.3]], OAR's database schema version must be 2.5.2 but is actually 2.5.0 in case of a fresh database setup with oar-database.

This unfortunately causes the upgrade of the database to a later version of OAR (e.g. [[:OAR 2.5.4]]) to report an error:
<code=bash>
root@server:~# oar-database --check
[Failed] OAR database version mismatch. Current version is 2.5.0 while 2.5.4 is required.
root@server:~# 
root@server:~# oar-database --upgrade
WARNING: Please make sure to stop oar-server service before upgrading.
         Please consider backing up the database before upgrading.
Continue? [y/N]: y
The current schema version is 2.5.0. Upgrading to 2.5.4.
Uprgading from '2.5.0' to '2.5.2'...
ERROR:  column "array_index" of relation "jobs" already exists
Uprgading from '2.5.2' to '2.5.4'...
root@server:~# 
</code>

=== Description of the fix procedure===

First check that your are actually using OAR 2.5.2 or OAR 2.5.3, e.g:
<code bash> 
$ /usr/sbin/oarnotify -V
OAR version : 2.5.3 (Frog Master)
</code>

It the reported version is indeed 2.5.2 or 2.5.3, follow the procedure adapted to your database backend.

== Mysql database ==
Check your database schema version:
<code bash>
# adapat the following to your configuration:
$ OARDBNAME="oar"
$ OARDBUSER="oar"
$ OARDBPASSWD="..."
$ echo 'select * from `schema`;' | mysql -t -u$OARDBUSER -p$OARDBPASSWD $OARDBNAME
+---------+------+
| version | name |
+---------+------+
| 2.5.0   |      |
+---------+------+
</code>

Check that your jobs table already has a "array_index" column.
<code bash>
$ echo 'select array_index from jobs limit 1;' | mysql -t -u$OARDBUSER -p$OARDBPASSWD $OARDBNAME
+-------------+
| array_index |
+-------------+
| .....       |
+-------------+
</code>

If yes, that confirms that the current version of your OAR database is 2.5.2 already and that the schema version is wrong. 

Please apply the following command to fix the version:
<code bash>
$ echo 'update `schema` set version = "2.5.2";' | mysql -u$OARDBUSER -p$OARDBPASSWD $OARDBNAME
# Then, check the version again:
$ echo 'select * from `schema`;' | mysql -t -u$OARDBUSER -p$OARDBPASSWD $OARDBNAME
+---------+------+
| version | name |
+---------+------+
| 2.5.2   |      |
+---------+------+
</code>

== Postgresql database ==

Same as with MySQL, but use the psql command instead of the mysql command, e.g.:

<code bash>
$ echo 'update schema set version = "2.5.2";' | psql -h $SERVER oar oar -W
</code>