Add a -n option to the db_load(1) This option causes db_load(1) to refuse to overwrite already existing key/data pairs in databases.
Add a -N option to the db_stat(1) This option keeps db_stat(1) from acquiring region locks when reading shared regions, which allows db_stat(1) to be used to display information about regions where applications have crashed while holding region locks.
Add region reference counts and sizes to all db_stat(1) region displays.
The mutex locking code has been enhanced to no longer attempt full test-and-set instructions unless there is a strong probability of acquiring the mutex. This makes spinning on the mutex significantly less expensive.
Full test-and-set instructions are necessary on some architectures, and it this change actually decreased performance in some cases.