No or limited use of FieldCache

[Per Steffensen]

Hi

We have a SolrCloud setup handling huge amounts of data. When we do 
group, facet or sort searches Solr will use its FieldCache, and add data 
in it for every single document we have. For us it is not realistic that 
this will ever fit in memory and we get OOM exceptions. Are there some 
way of disabling the FieldCache (taking the performance penalty of 
course) or make it behave in a nicer way where it only uses up to e.g. 
80% of the memory available to the JVM? Or other suggestions?

Regards, Per Steffensen