Don't know if this will offer insight or not. I maintain a site with
over 18,000 html docs to index. I tried to make a single swish-e index
of all the pages but it ran out of memory before the half-way mark. I
wound up having to make several separate index files(5) which works out
reasonably well except that I have yet to be able to sort the results
from the index files in order to have the relevance numbers appear
correctly(in order).

-Stuart