I've been using the 'join' query parser to 'filter out' related documents
that should not be part of the result set. Functionally, it is working
fine. However, when we throw a 'real' level of customer traffic at it, it
pretty much brings Solr to its knees. CPU increases ALOT. Close to 3X,
when I enable this feature in our system. Solr response times shoot up,
and thread counts shoot up. Before I 'give up' on the join query parser, I
thought I'd seek some advice here.
So, when this feature is enabled, this negative &fq gets added:
-{!join fromIndex=primary_rollup from=group_id_mv to=group_member_id
score=none}${q}
The 'local' collection size is about 27 million docs, but the number of
docs that actually contain a 'group_member_id' is only about 125k. And, in
the 'fromIndex' collection, there are only 80k documents in that
collection, and they all have the 'group_id_mv' field. The 'fromIndex'
collection is a single shard, with a replica on each shard of the local
collection. The local collection only has about 300k docs per shard, at 96
shards.
I guess I'm just trying to understand why this appears to be causing such
problems for Solr, as the amount of work (the # of documents involved)
seems relatively small.
I hope I'm missing something...
Thanks for any input.
