Code review comment for lp:~jtv/launchpad/bug-408206

= Bugs 408067, 408319 =

It seems that ddtp-ubuntu is using export-to-branch now. These are the
Ubuntu package descriptions, and by far our largest translation files.
Whatever new ground this project steps on with Translations, it finds
some quicksand.

The export takes too long, and gets killed by a database watchdog. The
script is built to resume after such a failure, but the iteration of
productseries to service then breaks around item #10. Apparently it's
getting batched, with the transaction the result is coming from already
broken.

This branch fixes three issues exposed by this failure:

 * The transaction gets too long. This fix commits after every
   translation file as well as after every productseries.

 * Failures are logged as Warning, not as Error. Failures like this one
   shouldn't be fatal to the script, but it starts logging them as
   errors anyway.

 * After the error the script keeps iterating over a result set it first
   acquired before the abort. That becomes a shortlist, limited to a
   reasonable number of productseries for the script to hold in memory.

None of these are particularly testworthy. To QA, re-enable ddtp-ubuntu
exports and see what breaks next. :-)

Jeroen