Migration only doing one row at a time? I have a migration class set up that takes from an XML source ID list that points to individual XML files with data which is then imported into nodes.  The migration works but only one at a time.  There are no errors in the messages for migration, apache error log, syslog, and doing drupal_debug in all steps of the migration only shows that the migration goes through one row then stops.  

Is there any common issue that might be causing this behavior?
The issue was a standard PHP issue in a function that was being called during the batch operation.  In this case, the error does not matter, what matters is that I could not see anywhere that the error was happening.  

Running migrations via the Migrate UI will not show errors, in some cases, anywhere.  To better troubleshoot it is recommended that migrations are run via Drush.  Running my migration through Drush I was able to see where the import was failing and why.