Hi Irina, Yes, the "fromIndex" parameter can be used to perform a join from the host collection to a separate, single-shard collection in SolrCloud. If specified, this "fromIndex" collection must be present on whichever host is processing the request. (Often this involves over-replicating your "fromIndex" so that it's co-located with the other involved collection).
Additionally, Solr has recently gained support for "Cross Collection Joins". This separate approach to joining avoids the restrictions mentioned above. This is documented here: https://lucene.apache.org/solr/guide/8_6/other-parsers.html#cross-collection-join Best, Jason On Wed, Oct 7, 2020 at 12:45 PM Irina Kamalova <iren.kamal...@gmail.com> wrote: > > I suppose my question is very simple. > Am I right that if I want to use joins in the single collection in > SolrCloud across several shards, > I need to use semantic "fromIndex"? > According to documentation I should use it only if I have different > collections. > I have one single collection across multiple shards and I didn't find a way > to join documents correctly, but with "fromIndex" semantic. > > Am I correct? > > Best regards, > Irina Kamalova
