Berkeley DB: private copy?

[Bron Gondwana]

On Wed, Sep 22, 2010 at 04:43:23PM +0530, Shuvam Misra wrote:
> I'm open to criticism, but I strongly feel Cyrus should carry its own
> version of some of these critical system libraries, specially those ones
> which have caused so much compatibility grief in its history. I know this
> is considered 'bad taste', but the sysadmin who just wants a stable Cyrus
> server probably cares less about taste than stability.

It's quite justifiable in the case of BDB.  Unfortunately, not so much in
the case of SASL which is the other usual suspect.  SASL tends to be
deeply integrated into the rest of the system.

The other interesting one is openssl - but I don't think we have many
problems with it.  Not having openssl kind of sucks with 2.4 though.
Would suck less if we put our own crc32 and sha1 implementations in
the code.
 
> BTW, a basic question: why do we face more problems with Berkeley DB than
> with other file formats?

Environments mainly.  It does this funky "environment" thing which makes
it very susceptible to any errors in open/close counts between processes.
It's really not as robust in a multi-processor shared environment as
one could hope.

And we're probably using it wrong.  Except I don't know how, or what
to change.  Skiplist is nicely self-contained and relatively bug-free
these days.  We use pure skiplist at FastMail, and we still get
scads of DBERROR messages when we start and stop due to BDB environment
counts going negative.

Bron.