Figured out that offset is used as part of the grouping patch which I applied
(SOLR-8776) :
solr/core/src/java/org/apache/solr/handler/component/QueryComponent.java
+ if (query instanceof AbstractReRankQuery){
+ topNGroups = cmd.getOffset() +
((AbstractReRankQuery)query).getReRankDocs();
+ } else {
+ topNGroups = cmd.getOffset() + cmd.getLen();----- --Ilay -- Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html
