Binary Matching Operators (cont.)

• Hash Join

  • Works quickly if build input is smaller than memory
  • Must be concerned with overflow & skew
    • Use same methods as mentioned in general hashing section
    • Both inputs use the same partitioning algorithm
  • Obtain final result from combining the results of the partitioned files

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Concept: build a hash table on smaller, build input & search the table using the other, probe input.