title: What are atomikos transaction logs used for?
body: <p>I've inherited an application that uses Atomikos for transaction handling in Spring on top of an Oracle database.  In production deployments transaction logging has always been enabled by setting com.atomikos.icatch.enable_logging=true but the truth is I can't find any info on what exactly these logs are used for.</p>
  
  <p>The atomikos site states "this should never be disabled on production or data integrity cannot be guaranteed" and I found a comment in a jta.properties on that site that said there is a "risk of losing data after restart or crash" if it is disabled.</p>
  
  <p>We don't enable this in our development environments and are able to use the application normally.  I thought they might be used in the case of the application crashing but if so I'm not sure how they'd be used.  Maybe automatically during the next startup or manually in some way?  In terms of data integrity I know Oracle enables it's own data recovery but maybe these transaction logs hold data that Oracle hasn't seen yet, e.g. if Spring were to crash.</p>