A possible fix for SERVER-20176 requires some way to flush the logs explicitly.

geert.bosch tried a WT_SESSION.begin_transaction and WT_SESSION.commit_transaction pair, with commit_transaction configuring sync=on, but that won't work unless there are writes included in the transaction.

sue.loverso suggests it might be possible to make that work (and it's not unreasonable since the documentation does imply sync=on flushes all log records. (The documentation says "whether to sync the log on every commit by default", without any discussion of a write being required.)

sue.loverso also suggested WT_SESSION.transaction_sync could be enhanced to provide this functionality, perhaps calling that method without any configuration would flush the log.

sue.loverso, michael.cahill