sharding - how mongodb scales when you have relationships between collections? -

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i have mongodb links documents (the data cannot embedded)

does mongos cluster (http://docs.mongodb.org/manual/core/sharding-introduction/) support sharding when documents linked?

how impacts performance?

thanks!

considering there nothing special referenced documents, logical relationship inferred application layer , not mongodb itself, sharding supported. applies "manual" references, dbrefs. can shard on dbref property, although i'm not sure why you'd want considering dbref should have inherently low cardinality.

there impact in performance both manual , dbrefs, in multiple queries must performed "join" data. docs:

to resolve dbrefs, application must perform additional queries return referenced documents. many drivers have helper methods form query dbref automatically. drivers not automatically resolve dbrefs documents.


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