Description

Summary

• SmartJoins SmartJoins - Making distributed Join Operations Local When sharding data collections to a cluster, running JOIN operations across data residing on different machines might require large amounts of data movements and network traffic and hence suboptimal performance.
• Within the orders collection the productId is a foreign key referencing to the _key attribute in the products collection and by using this attribute as the sharing key for the orders collection guarantees that orders and products are sharded alike and SmartJoins can be used.
• The intermediate results from the DBservers get then send to the Coordinator, where the final result set gets put together and send to the client (see schema below).
• In such cases, joins across all three collections could be performed locally thanks to the combination of SmartJoins (product and order collections) and SatelliteCollections (user collections).