Damiano, I don’t really have a direct answer for you. However, one of the aspects of Streaming that I really like is that it’s relatively easy to create your own operators and add them to Solr. I find that I often just create my own operator to fill in the gap of what is available.
I do think joining disparate datasets to make new datasets is one of the most interesting uses of Streaming, so would love to see what you cook up. Eric > On Dec 29, 2021, at 6:39 AM, Damiano Albani <damiano.alb...@gmail.com> wrote: > > Hello, > > I'm new to streaming expressions, so I'm trying to understand their > features and limitations. > In particular the so-called "stream operators" implementing join operations. > Like "innerJoin", "leftOuterJoin", etc. > > I see that they support a "on" parameter, defining the *equality* check to > be performed. > But, coming from the SQL world, I'm used to being able to use a variety of > comparison operators in join predicates. That is, not only equality, as in > "equi-joins". > > Is there a reason why the current implementation of Solr supports > equi-joins only? Would it be technically possible (and desired) to support > other comparison operators with joins? > And maybe somehow allow the use of the available stream evaluators > <https://solr.apache.org/guide/8_11/stream-evaluator-reference.html>? > > To give the context of my question: I'm trying to join 2 sets of documents > with a hierarchical relationship. > My goal is to join them using a "path" field on one side and > "descendent_path" field on the other side. > But it looks like that only doc values are accessible (and not analyzed > ones) in streams, so I suppose I'd be left with a join criteria like this > pseudo-code: > >> on="starts_with(right.path, left.path)" > > Where, in this hypothetical example: > >> left.path=/categories/category1" >> right.path=/categories/category1/sub-categories/sub-category-a" > > > Or do I completely misunderstand how Solr (streams) work? ;-) > Thanks for your help! > > Regards, > > -- > Damiano Albani _______________________ Eric Pugh | Founder & CEO | OpenSource Connections, LLC | 434.466.1467 | http://www.opensourceconnections.com <http://www.opensourceconnections.com/> | My Free/Busy <http://tinyurl.com/eric-cal> Co-Author: Apache Solr Enterprise Search Server, 3rd Ed <https://www.packtpub.com/big-data-and-business-intelligence/apache-solr-enterprise-search-server-third-edition-raw> This e-mail and all contents, including attachments, is considered to be Company Confidential unless explicitly stated otherwise, regardless of whether attachments are marked as such.
