Complex Query Plan Execution (cont.)

• Better Ideas

  • Decomposition
    • Modified Ingres Decomposition
  • Prediction
    • Use a decision tree of subplans
    • Done by using choose-plan operators

• Major Concern

  • Optimal resource allocation

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Ingres Decomposition:

3 step cycle- select the operation, execute operation in a temporary table, & remove predicates evaluated in step 2 and replace one range variable in the query with the table from step 2.

Choose-plan operators work by doing 0 or more subplans and then choosing which of 2 or more plans to execute.

Resource allocation: optimal if marginal gains are balalnced among all requestors for each resource.