On 11/5/2015 10:25 PM, Jack Krupansky wrote: > I vaguely recall some discussion concerning removal of the field cache in > Lucene.
The FieldCache wasn't exactly *removed* ... it's more like it was renamed, improved, and sort of hidden in a miscellaneous package. Some things still require this functionality, so they use the hidden class instead, which was changed to use the DocValues API. https://issues.apache.org/jira/browse/LUCENE-5666 I am not qualified to discuss LUCENE-5666 beyond what I wrote in the paragraph above, and it's possible that some of what I said is wrong because I do not really understand the APIs involved. The change has caused problems for Solr. End result from Solr's perspective: Certain things which used to work perfectly fine (mostly facets and grouping) in Solr 4.x have one of two problems in 5.x: Either they don't work at all, or performance has gone way down. Some of these problems are documented in Jira. These are the issues I know about: https://issues.apache.org/jira/browse/SOLR-8088 https://issues.apache.org/jira/browse/SOLR-7495 https://issues.apache.org/jira/browse/SOLR-8096 For fields where adding docValues is a viable option (most field types other than solr.TextField), adding docValues and reindexing is very likely to solve those problems. Sometimes adding docValues won't work, either because the field type doesn't allow it, or because it's the indexed terms that are needed, not the original field value. For those situations, there is currently no solution. Thanks, Shawn
