Nested streaming expression with differing "on" fields

[Sarvothaman Madhavan <re...@gmail.com>]

Hello solr users,

Is it possible to perform streaming expression of the following type:


intersect(
	search (collection_3, fl=“field_1,field_2",sort="field_2 asc",qt="/export",q=*:* ),
	intersect( 
		search (collection_1, fl=“field_1,field_2",sort=“field_1 asc",qt="/export",q=*:*),
		search (collection_2, fl="field_1,field_2",sort=“field_1 asc",qt="/export",q=*:*),
		on=“field_1"
	), 
	on=“field_2"
)

Currently I get a “Invalid ReducerStream - substream comparator (sort) must be a superset of this stream's comparator.” 

Logically, collection_1 and collection_2 are linked via field_1 but the collection_3 links to everything else via field_2. The other point to note here is that this expression is build dynamically based on inputs to the program. 

Any workaround that you guys can point to will be useful. 

Thanks,
Sarvo