ovdb update

[Heath Kehoe]

>>[...]
>
>This sounds very cool, and similar to some of the plans Aidan had at one
>point to spawn off nnrpd helper processes.  (I think one of the original
>intentions there was to see if caching overview data across multiple
>nnrpds would help performance, but I think BerkeleyDB is already doing
>some of that, right?)
>

Yah, BerkeleyDB does extensive caching, but the readserver thing probably
won't change caching performance.  One big benefit that I didn't mention
is that having only a few processes accessing the database reduces
lock contention within the database.  Which means that innd won't be
slowed down as much when there are lots of readers (in theory... I
havn't verified that yet).

-heath