Paged results and multiple bdb backends.

[Brandon Hume <hume-ol@bofh.ca>]

Okay, I've isolated what appears to be part of the problem, and
something I overlooked in our upgrade from 2.2 to 2.3: We also split the
existing tree into multiple BDB backends.  Several isolated branches of
the tree were quite large, and this was an attempt to split the database
in multiple, more-managable chunks.  We were also looking at partial
replication of just one portion of the tree.

Now, as I muck about on a test server, I see that if I edit slapd.conf
so that only one backend is enabled, I have functional paged results.
If I enable a subordinate database, paged results fail with the
previously mentioned "old or invalid" error.

So, at least I have a fallback plan to get this working: merge it all
back into the single BDB database.  I'd like to avoid that if I can,
though.

Are there tricks to using the paged results control when searching
across multiple backends?