John Davis <johndavis925...@gmail.com> wrote: > We are seeing really slow facet performance with new solr release. > This is on an index of 2M documents.
I am currently running some performance experiments on simple String faceting, comparing Solr 4 & 6. There is definitely a performance difference, but it is not trivial to pinpoint where it is. My first thought was that it was tied to the Solr version, with Solr 6 being markedly slower than Solr 4. However, looking at segment count, I can see that Solr 6 has twice as many segments as Solr 4 for my test setup. I tried optimizing down to 10 segments, which flipped the result: Suddenly Solr 6 was faster than Solr 4. I'm still poking at this, but I guess my takeaway for now is to be sure to compare on fair terms. The strategy for creating segments can be tweaked and (guessing a lot here) it seems that Solr 6 defaults leans towards faster indexing (by having more small segments) at the cost of faceting performance. These JIRAs seems relevant: https://issues.apache.org/jira/browse/SOLR-8096 https://issues.apache.org/jira/browse/SOLR-9599 > 1. method=uif however that didn't help much (the facet fields have > docValues=false since they are multi-valued). Debug info below. docValues works fine with multi-values (at least for Strings). - Toke Eskildsen
