RE: Adding attributes (in a massive way)....

["Howard Chu" <hyc@highlandsun.com>]

> -----Original Message-----
> From: owner-openldap-software@OpenLDAP.org
> [mailto:owner-openldap-software@OpenLDAP.org]On Behalf Of Frank Swasey

> Today at 1:55am, Michael Ströder wrote:
> > Frank Swasey wrote:
> > > Today at 3:18pm, Michael Ströder wrote:
> > > >Which backend type?

> > > ldbm using bdb 4.0

> > Correct me if I'm wrong but IMHO slapadd with bdb is much
> > slower than with ldbm. Therefore you former performance comparison of
> > slapadd and ldapmodify might solely apply to ldbm backend.

"IMHO" -> opinions are neither right or wrong.  ;)

Due to transaction logging, back-bdb can be slower than back-ldbm. If you use
it as recommended, with the transaction logs on a separate disk from the main
database, it is generally faster than back-ldbm. Even with logs on the same
disk, back-bdb is usually faster than back-ldbm, because back-bdb's storage
format and coding is more efficient.

> I would recommend using a DB_CONFIG file during the slapadd that turned
> off the writing the db after every transaction (I'm at home, and don't
> remember the command) to speed up the bdb.

assuming a default logfile size of 10MB, I recommend:

set_flags DB_TXN_NOSYNC
set_lg_bsize 2097152

> Of course, IMHO, backend bdb isn't ready to be the production backend.
> There's no documentation on how to maintain it in the administrator's
> guide (or wasn't at my last reading).  You have to go read the C
> programmers reference material on sleepycat and extrapolate to the
> commands you would want to run on a regular basis.  Further, the

You're welcome to submit documentation of your own for
review/adaptation/adoption.
Currently my position is that it's a needless duplication of effort for us to
write documentation on how to use the SleepyCat database. Their documentation
is extensive, and you need to understand it in order to properly
tune/maintain the database. Recommendations like the one I made above are
useless if thrown into the wrong context; or blindly followed without knowing
the underlying assumptions.

> developer's list still is talking about bugs and changes to the
> operation of bdb (granted there are still bugs in the ldbm code).

Operational changes being discussed won't be visible until OpenLDAP 2.2 is
released, whenever that is. Bugs will of course be fixed as soon as is
practical, but otherwise back-bdb in OpenLDAP 2.1 is in its final form.

back-ldbm is another story; there are so many things it does wrong that
really, back-bdb *is* the bugfix for back-ldbm.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support