We should make some precision here, When dealing with faceting , there are currently 2 main approaches :
1) *Enum Algorithm* - best for low cardinality value fields, it is based on retrieving the term enum for all the terms in the index, and then intersecting the related posting list with the query result set 2) *Un-Inverting Algorithms* - Best for high cardinality value fields, it is based on uninverting the index, checking the value for each query result document field, and counting the occurrences Within the 2nd approach : 2a) *Doc Values * - It is better for dynamic indexes, built at indexing time and stored on the disk ( setting the specific attribute for the field) OR calculated at runtime thanks to the UnInvertedReader that will uninvert to an in-memory structure that looks like DocValues 2b) *Uninverted field* - for index that changes less frequently . After the removal related : Only per segment field caches are available, which means you should be able to use it using the fcs algorithm. This should be the current situation, I will take a look into details and let you know if I understood something wrong. Cheers 2015-10-06 5:03 GMT+01:00 William Bell <billnb...@gmail.com>: > So the FieldCache was removed from Solr 5. > > What is the implication of this? Should we move all facets to DocValues > when we have high cardinality (lots of values) ? Are we adding it back? > > Other ideas to improve performance? > > From Mike M: > > FieldCache is gone (moved to a dedicated UninvertingReader in the > miscmodule). > This means when you intend to sort on a field, you should index that field > using doc values, which is much faster and less heap consuming than > FieldCache. > > -- > Bill Bell > billnb...@gmail.com > cell 720-256-8076 > -- -------------------------- Benedetti Alessandro Visiting card - http://about.me/alessandro_benedetti Blog - http://alexbenedetti.blogspot.co.uk "Tyger, tyger burning bright In the forests of the night, What immortal hand or eye Could frame thy fearful symmetry?" William Blake - Songs of Experience -1794 England
