Turning on archiving requires a simple stanza which will turn on archiving for the use sending the stanza and using default settings.
<iq type='set' id='turnon'> <pref xmlns='urn:xmpp:archive'> <auto save='true'/> </pref> </iq>
A sucessful result will yield this response from the server:
<iq type='result' to='user@domain.com' id='turnon'/>
Once this is turned on, incoming and outgoing messages from the user will be stored in tig_ma_msgs table in the database.