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…Hash Join Process

Notes:

Hash join process continued from the previous page:
Start reading rows from the second table. For each row read:
hash the join key value. This produces a pointer into the memory-based array.
Scan the array looking for a match.
Return the joined row to the client if match found.
With a hash join, one of the tables is used to create a hash table, optimally all in private memory. As the second table is read, the join key values are hashed and the result of the hash algorithm is used to probe the hash table. Once this phase of the process starts, the rows start quickly returning to the caller.