I think the answer is that you have to co-locate the docs with the same value you're grouping by on the same shard whether in SolrCloud or not...
Hmmm: from: https://cwiki.apache.org/confluence/display/solr/Result+Grouping#ResultGrouping-DistributedResultGroupingCaveats "group.ngroups and group.facet require that all documents in each group must be co-located on the same shard in order for accurate counts to be returned." Best, Erick On Fri, Mar 17, 2017 at 8:00 AM, Shawn Heisey <apa...@elyograg.org> wrote: > We use pagination (start/rows) frequently with our queries. Nothing > unusual there. > > Now we have need to use grouping with a request like this, for a > set-mode search, where only one document from each set is returned: > > http://idxb1.REDACTED.com:8981/solr/ncmain/lbcheck?q=*:*&group=true&group.field=set_name&group.sort=set_lead%20desc&group.limit=1&rows=50 > > We've worked through most of the problems encountered with this idea. > The first page of results works perfectly. > > The remaining problem is that I cannot seem to paginate -- set the start > value to 50, 100, etc. I found some information saying that > group.ngroups=true is required for pagination, so I added that. I have > found that occasionally I can load page two (rows=50&start=50), but that > *most* of the time, I can't even get page two to load, and further pages > have never worked. The response contains no documents. > > The index is distributed (sharded), but not running SolrCloud. > > The server where I am trying this is running a SNAPSHOT build of 4.9. I > haven't had an opportunity yet to try a newer version -- we don't have > newer versions on any of the machines for this index. I can only > upgrade as far as 5.3, because that's as far as we can go with a > third-party plugin we are using. > > I found the following issue, which says it was fixed before 4.0 was > released: > > https://issues.apache.org/jira/browse/SOLR-2207 > > Does anyone know whether pagination with grouping is expected to work, > and if so, how to do it? > > Thanks, > Shawn >
