On 2/24/2016 9:58 AM, Lokesh Chhaparwal wrote: > Can someone please update on this exception trace while we are using > distributed search using shards parameter (solr-master-slave).
The line of code where the NPE happened (from the 4.7.2 source) is in XMLWriter.java, at line 190: for (String fname : doc.getFieldNames()) { This means that "doc" is null. This variable is pulled out of a SolrDocumentList object, which means that whatever created that SolrDocumentList managed to add a null entry. I ran into a nearly identical stacktrace last year: https://mail-archives.apache.org/mod_mbox/lucene-solr-user/201509.mbox/%3c55f9e5df.1050...@elyograg.org%3E I never did get a response to that message on the mailing list, and I can no longer recall exactly what I did to fix it. What little I do remember suggests that this was caused by a situation where the field I was grouping on was not present in at least one document. This situation should have been impossible in our data set, but occasionally a badly formatted document will result in bad data in the database used to populate Solr, which causes unexpected behavior. Is this perhaps a query that uses grouping? A similar problem might happen with facets, but I am unsure about that. Thanks, Shawn