Dynamic redistribution or broadcasts

If your database design or data distribution precludes you from distributing certain tables on the join key (column), the IBM® Netezza® system dynamically redistributes or broadcasts the required data.

When the system redistributes data, it sends each record in the table to a single SPU, but, which SPU depends on the record. Each SPU scans its own portions of the table and extracts only the needed columns, determines the destination SPU, and transmits the records across the internal network fabric. The system performs these operations in parallel across all SPUs.

When the system broadcasts data, it sends every record in the table to every SPU. Depending on the size of the table and the way the data is distributed, one method might be more cost-effective than the other.