Physical Database Design

6.7 Database Design Tips for Reducing Cross-node Data Shipping 115

JOB_ID. The global join index may reduce the amount of cross-node traffic even when

collocation is not perfect. This index type will require additional storage for the RIDs

that point back to the base table. Generally speaking, the storage requirements for the

RIDs are a relatively small overhead when the index keys are more than 8 bytes wide.

The wider the index key, the less concern the designer needs to have over the overhead

of the RIDs in the global join index.

6.7.3 The Internode Interconnect

There will always be some degree of communication between shared-nothing partitions.

Even when data is perfectly collocated, results from each data node will need to be

merged into a result ...