On Sat, May 24, 2014 at 9:50 PM, 张月祥 <zhan...@calis.edu.cn> wrote: > Thanks for your reply. I'll try it. > > We're still interested in the real limitation about "Too many values for > UnInvertedField faceting on field xxx" . > > Could anybody tell us some internals about "Too many values for > UnInvertedField faceting on field xxx" ?
There are only 256 byte arrays to hold all of the ord data, and the pointers into those arrays are only 24 bits long. That gets you back to 32 bits, or 4GB of ord data max. It's practically less since you only have to overflow one array before the exception is thrown. This faceting method is best for high numbers of unique values, but a relatively low number of unique values per document. I've been considering making an off-heap version for Heliosearch, and maybe bump the limits a little at the same time... -Yonik http://heliosearch.org - facet functions, subfacets, off-heap filters&fieldcache
