Sort-field for ALL docs in FieldCache for sort queries -> OOM on lots of docs

[Per Steffensen]

Hi

We have a lot of docs in Solr. Each particular Solr-node handles a lot 
of docs distributed among several replica. When you issue a sort query, 
it seems to me that, the value of the sort-field of ALL docs under the 
Solr-node is added to the FieldCache. This leads to OOM-exceptions at 
some point when you have enough docs under the Solr-node - relative to 
its Xmx of course. Are there any "tricks" to get around this issue, so 
that a sort-query will never trigger a OOM, no matter how many docs are 
handled by a particular Solr-node. Of course you need to be ready to 
accept the penalty of more disk-IO as soon as the entire thing does not 
fit in memory, but I would rather accept that than accept OOM's.

Regards, Per Steffensen