Change from pgsql to internal

So you use pgsql only for authentication? Or do you use also mod_roster_odbc, ...?

If you only use for auth, then you only need ejabberd to create an item for each user in the Mnesia table 'passwd', with the info: username, domain, password. There are two possible ways: create the accounts as usual, or manually edit the table. I don't know which one is better, so I'll explain how to make the difficult one :)

1. Export your pgsql database to text file
2. Convert the file to the format used by Mnesia text dumps.
3. For example, to add the users 'tom' with password 'tutu9' and 'bobby' with password 'gj45' to the vhost 'localhost', I create the file /tmp/justusers.dump with this content:
   

   {tables,[
            {passwd,[{record_name,passwd},{attributes,[us,password]}]}
   ]}.
   {passwd,{"tom","localhost"},"tutu9"}.
   {passwd,{"bobby","localhost"},"gj45"}.

4. Now go to the ejabberd webadmin, and in Nodes -> your node -> DB Backups, Restore text file backup, put the full path to your file and Accept.

I tested this, and importing that file didn't remove any information: the other accounts and the rosters are intact. But anyway, you may want to make a binary backup before doing all this process.