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Re: [ANNOUNCE] Berkeley DB 4.4.16 (fwd)



Quanah Gibson-Mount wrote:
Here's the BDB 4.4 release announcement... I have some questions about this & OpenLDAP inline.

Gregory Burd <gburd@sleepycat.com> writes:

Sleepycat Software is pleased to announce:
        Berkeley DB 4.4.16
        http://www.sleepycat.com/products/bdb.html

The Berkeley DB 4.4 release introduces a number of important new features
in three major functional areas.
The first area is in limiting when database environment recovery needs
to be performed. The Berkeley DB 4.4 release introduces the ability
to abort transactions and release locks held by processes that have
failed, without exiting the database environment and performing
recovery. In addition, the 4.4 release also introduces the ability to
serialize the database environment creation process, performing
recovery automatically as necessary. This feature can significantly
simplify the architecture of applications comprised of multiple
concurrent processes.

Since BDB now does auto-recover, is alock going to cause conflicts?

There is no conflict since you have to explicitly request this feature. However, it appears that the BDB 4.4 feature is more useful than alock, since it will release locks held by exited processes. That means explicit recovery/cleanup steps will be far less frequent. Previous BDB releases didn't record the thread or process ID that owned a lock, so it simply wasn't possible to only cleanup dangling locks. Now that BDB 4.4 records these owner IDs, deadlock debugging will be a lot easier too.


--
 -- Howard Chu
 Chief Architect, Symas Corp.  http://www.symas.com
 Director, Highland Sun        http://highlandsun.com/hyc
 OpenLDAP Core Team            http://www.openldap.org/project/