Hi Eric, Thanks for your feedback, I highly appreciate it. I don't mind going the route of implementing something myself. I will have a try. By any chance, apart from looking at the official codebase, do you know of any examples out there I could draw my inspiration from?
Regards, On Wed, Dec 29, 2021 at 3:08 PM Eric Pugh <ep...@opensourceconnections.com> wrote: > 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. > > -- Damiano Albani
