Since many fields are single valued, start the ArrayList with capacity 1 -- this should help with GC. http://www.nabble.com/Re%3A-svn-commit%3A-r547493---in--lucene-solr-trunk%3A-.--src-java-org-apache-solr-common--src-java-org-apache-solr-schema--src-java-org-apache-solr-update--src-test-org-apache-solr-common--tf3931539.html#a11159518
lucene/solr/trunk/src/java/org/apache/solr/common/SolrDocument.java