At some point my Apple wiki wanted to upgrade which included an upgrade of Postgres from 9.2 to 9.3. I think a premature reboot cause the upgrade process to break it.
This is what fixed it:
First open Terminal App and sudo su <return> to become root…
You may see several folders here. Mine contained the following folders:
If you don’t see these, this procedure probably won’t work for you. I advise you to backup this folder either way just be be on the safe side.
Cluster.pg is where the postgres configuration file under the /Library/Server/Wiki/Config folder points to for the collab database.
First make sure wiki and collabd are not running
serveradmin stop wiki
serveradmin stop collabd
Remove the collab database your wiki is pointing to
rm -R Cluster.pg Cluster.pg
mv Cluster.pg.original_for_upgrade Cluster.pg
mv Cluster.pg.new_for_upgrade Cluster.pg.new_for_upgrade_
chmod -R 700 Database.xpg
chmod -R 750 FileData
chown -R _teamsserver:_teamsserver *
serveradmin start wiki
serveradmin start collabd
Wait a while.
Point your browser to your wiki.