Merge branch 'experiment-files-650'
Give dummy request the _stats dict. The stats events are setup to listen on all Engines.
Use subprocess postgres for tests by default (avoid sqlite segfault.)
Fix transaction record row insert after a savepoint rollback.
Fix transaction recording.
Fix sync_edw.get_all_datasets to use correct loop variable.

The tests here are really brittle and could really do with reworking sometime.
Merge remote-tracking branch 'origin/master' into sync-options-1145
cannot resolve extra post on 409