Table of Contents

Two notions of Parallel query processing

In Distributed Query Processing, the results are all stored in a single “head” node. In Parallel Query Processing, the results are stored across many nodes.

In Distributed Query Processing, queries are processed in parallel and the results are stored in a single “head” node. In Parallel Query Processing, queries are processed in parallel in parallel and stored among many nodes.

Distributed Query

  • Rewrite the query as a union of subqueries
  • Workers communicate through standard interfaces, so compatible with federated, heterogeneous, or distributed databases

Parallel Query

  • Each operator is implemented with a parallel algorithm. See Teradata