Hi, Here is a discussion we had recently with a fellow Solr user. It seems reasonable to me and wanted to see if this is an accepted theory.
The bit-vectors in filterCache are as long as the maximum number of documents in a core. If there are a billion docs per core, every bit vector will have a billion bits making its size as 10 9 / 8 = 128 mb With such a big cache-value per entry, the default value of 128 values in will become 128x128mb = 16gb and would not be very good for a system running below 32 gb of memory. If such a use-case is anticipated, either the JVM's max memory be increased to beyond 40 gb or the filterCache size be reduced to 32. Thanks SG
