Hello ilayaraja, I think it would be good to move this discussion on the Jira item:
https://issues.apache.org/jira/browse/SOLR-8776?attachmentOrder=asc You can add your comments there, and also in the page I explained how it works. On the performance you are right: at the moment it is slow. We recently improved the performance a lot for the particular use case where you are interested only in one document per group ( first part of the change has been upstreamed in the las vegas patch [1] ). For the general case, my opinion is that we could speed up by allowing the user to rerank only the groups (without affecting the order of the documents **within** each group). 1. How many top groups are actually re-ranked, is it exactly what we pass in reRankDocs? > rerankDocs will rerank the top $rerankDocs groups, so if your groups contain > many documents you will rerank much more documents 2. How many documents within each group is re-ranked? Can we control it with group.limit or some other parameter? > $rerankDocs documents will be reranked inside each group - please double > check on the jira and add your comments there. Cheers, Diego [1] https://issues.apache.org/jira/browse/SOLR-11831?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel&focusedCommentId=16316605#comment-16316605 From: solr-user@lucene.apache.org At: 05/08/18 07:07:01To: solr-user@lucene.apache.org Subject: LTR performance issues LTR with grouping results in very high latency (3x) even while re-ranking 24 top groups. How is re-ranking implemented in Solr? Is it expected that it would result in 3x more query time. Need clarifications on: 1. How many top groups are actually re-ranked, is it exactly what we pass in reRankDocs? 2. How many documents within each group is re-ranked? Can we control it with group.limit or some other parameter? What causes LTR take more time when grouping is performed? Is it scoring the documents again or merging the re-ranked docs with rest of the docs? Is there anyway to optimize this? ----- --Ilay -- Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html
