Hi Shawn,
It may be your facets that are killing you here. As Toke mentioned, you
have not indicated what your max heap is.20 separate facet fields with
millions of documents will use a lot of fieldcache memory if you use the
standard facet.method, fc.
Try adding facet.method=enum to all your facet queries, or you can put
it in the defaults section of each request handler definition.
Ok, that is easy to try out.
Alternatively, you can add docValues to all your facet fields, but that
will require a full reindex.
This will not be so easy to handle, so I'll try it only if nothing else
helps.
Thanks a lot,
Angel