bitcoin/bitcoin — pull request #1360 by jgarzik (2012-05-19 05:27:39+00:00)
Title: Default to DB_TXN_WRITE_NOSYNC for all transactional operations

* This is safer than DB_TXN_NOSYNC, and does not appear to impact
performance.
* Applying this to the dbenv is necessary to avoid many fdatasync(2)
calls on db 5.x
* We carefully and thoroughly flush databases upon shutdown and
other important events already.