Dear Mr. Bernstein, SOLR-users,
thanks a lot for your valuable hint regarding the cartesianProduct operator.
The following streaming expression gives me the desired result tuples:
hashJoin(
search(collection,q="type_s:child",fl="id_s",sort="id_s ASC",rows=1000000),
hashed=cartesianProduct(
search(collection,q="type_s:parent AND
id_s:p123",fl="children_ids_ss,id_s",sort="id_s ASC"),
children_ids_ss
),
on="id_s=children_ids_ss"
)
where the inner
search(collection,q="id_s:p123",fl="children_ids_ss,id_s",sort="id_s ASC")
ideally delivers 1 to a few (say 1000) tuples, hopefully not making the HashJoin
slow or even impossible, and the outer search will yield quite a lot tuples.
Which
should be fine though.
Cheers,
Marc
-----Ursprüngliche Nachricht-----
Von: Marc Röttig [mailto:marc.roet...@vico-research.com]
Gesendet: Mittwoch, 6. September 2017 10:08
An: solr-user@lucene.apache.org
Betreff: Streaming expression API innerJoin on multi-valued field
Dear SOLR users,
I want to use streaming expression innerJoin using a multi-valued field to do
the join by equality, that is having any child documents (of type "child") and
one parent document (of type "parent") join these according to equality of id_s
and children_ids
Parent
* id_s = "p123"
* type_s = "parent"
* children_ids_ss = "c1,c2"
Child
* id_s = "c1"
* type_s = "child"
Child
* id_s = "c2"
* type_s = "child"
innerJoin(
search(collection,q="type_s:child",fl="id_s",sort="id_s ASC"),
search(collection,q="type_s:parent",fl="id_s,children_ids_ss",sort="id_s
ASC"),
on="id_s=children_ids_ss"
)
This seems to be impossible, I am getting the following exception
"java.util.ArrayList cannot be cast to java.lang.Comparable". Using a
GraphQuery with from and to this relationship traversal along multi-valued
fields worked (however not between shards, this is why I switched to streaming
expressions).
Is there any mechanism to flatten the tuples with the multi-valued field into
new tuples with single-valued fields to get the join working ? Or any other
tweak.
Note: The relationship between Parent and Child is many-to-many, thus moving
the foreign-keys to the children as single-valued fields is not possible.
The issue is related tot he following issue:
http://lucene.472066.n3.nabble.com/Using-multi-valued-field-in-solr-cloud-Graph-Traversal-Query-td4324379.html
Thanks a lot in advance for any assistance, Marc
Dr. Marc Röttig
Software Developer
EMail: marc.roet...@vico-research.com
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