lucene-solr-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Joel Bernstein <joels...@gmail.com>
Subject Re: Joining more than 2 collections
Date Tue, 02 May 2017 18:04:51 GMT
Also take a look at the documentation for the "fetch" streaming expression.

Joel Bernstein
http://joelsolr.blogspot.com/

On Tue, May 2, 2017 at 2:03 PM, Joel Bernstein <joelsolr@gmail.com> wrote:

> Yes you join more then one collection with Streaming Expressions. Here are
> a few things to keep in mind.
>
> * You'll likely want to use the parallel function around the largest join.
> You'll need to use the join keys as the partitionKeys.
> * innerJoin: requires that the streams be sorted on the join keys.
> * innerHashJoin: has no sorting requirement.
>
> So a strategy for a three collection join might look like this:
>
> innerHashJoin(parallel(innerJoin(bigStream, bigStream)), smallerStream)
>
> The largest join can be done in parallel using an innerJoin. You can then
> wrap the stream coming out of the parallel function in an innerHashJoin to
> join it to another stream.
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> Joel Bernstein
> http://joelsolr.blogspot.com/
>
> On Mon, May 1, 2017 at 9:42 PM, Zheng Lin Edwin Yeo <edwinyeozl@gmail.com>
> wrote:
>
>> Hi,
>>
>> Is it possible to join more than 2 collections using one of the streaming
>> expressions (Eg: innerJoin)? If not, is there other ways we can do it?
>>
>> Currently, I may need to join 3 or 4 collections together, and to output
>> selected fields from all these collections together.
>>
>> I'm using Solr 6.4.2.
>>
>> Regards,
>> Edwin
>>
>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message