RE: berkeley db max filesize

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

> -----Original Message-----
> From: James Bourne [mailto:jbourne@mtroyal.ab.ca]

> On Thu, 15 Aug 2002, Howard Chu wrote:
> > This is mainly a Berkeley-specific question:
> > http://www.sleepycat.com/docs/ref/am_misc/dbsizes.html
> >
> > The default page size used by libldbm is 4096 bytes, which gives you 2^44
> > (16 terabytes) as the maximum database size. If you need more, you can
> > redefine the DEFAULT_DB_PAGE_SIZE macro and recompile libldbm. I doubt
> > that you'll need to do this any time soon.
>
> Right, looking at the source I see the page size (I was thinking
> it was the berk db default of 32k maybe?).  I wanted confirmation that the
> 2G problem won't be a problem user the berkeley db.  I had looked at their
> dbsizes table, but didn't know if there was anything internal to openldap
> to cause problems.

The database is pretty much a black box, OpenLDAP only cares about entries.
Since it uses 32-bit ints for entry IDs, you can only have 4 billion entries.
But I think that's OK; if you created one entry per second continuously you'd
wrap around in about 136 years and surely by then the owners of your older
accounts won't need them any more...

The only limits of interest are how much data you can keep in RAM at one
time,
because OpenLDAP retrieves whole entries from the database, even if you only
want one attribute. So your physical RAM size limits how large a single entry
can be, and how many entries can be cached at once, etc...

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