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Next: Join Strategies for Parallel Up: Join Strategies Previous: Hash Join

Three-Way Join

  1. We now consider the strategies for computing a 3-way join:

     branch  tex2html_wrap_inline828  deposit  tex2html_wrap_inline828  customer

  2. We'll assume that
  3. Strategy 1:
  4. Strategy 2:
  5. Strategy 3: Using strategy 3 it is often possible to perform a three-way join more efficiently than by using two two-way joins.
  6. It is hard to calculate exact costs for 3-way joins. Costs depend on how the relations are stored, distribution of values and presence of indices.

Osmar Zaiane
Sun Jul 26 17:45:14 PDT 1998