List of addOrLoadBestPlanMapping() Examples

Examples of addOrLoadBestPlanMapping()

org.apache.derby.iapi.sql.compile.Optimizable.addOrLoadBestPlanMapping()
When remembering "truly the best" access path for an Optimizable, we have to keep track of which OptimizerImpl the "truly the best" access is for. In most queries there will only be one OptimizerImpl in question, but in cases where there are nested subqueries, there will be one OptimizerImpl for every level of nesting, and each OptimizerImpl might have its own idea of what this Optimizable's "truly the best path" access path really is. In addition, there could be Optimizables above this Optimizable that might need to override the best path chosen during optimization. So whenever we save a "truly the best" path, we take note of which Optimizer/Optimizable told us to do so. Then as each level of subquery finishes optimization, the corresponding OptimizerImpl/Optimizable can load its preferred access path into this Optimizable's trulyTheBestAccessPath field and pass it up the tree, until eventually the outer-most OptimizerImpl can choose to either use the best path that it received from below (by calling "rememberAsBest()") or else use the path that it found to be "best" for itself. This method is what allows us to keep track of which OptimizerImpl or Optimizable saved which "best plan", and allows us to load the appropriate plans after each round of optimization. @param doAdd True if we're saving a best plan for the OptimizerImpl/Optimizable; false if we're loading/retrieving the best plan. @param planKey Object to use as the map key when adding/looking upa plan. If it is an instance of OptimizerImpl then it corresponds to an outer query; otherwise it's some Optimizable above this Optimizable that could potentially reject plans chosen by the OptimizerImpl to which this Optimizable belongs.

Examples of org.apache.derby.iapi.sql.compile.Optimizable.addOrLoadBestPlanMapping()

        ** because 'reloading best plans' involves walking the
        ** entire subtree of _every_ Optimizable in the list, which
        ** can be expensive if there are deeply nested subqueries.
        */
        if (reloadBestPlan)
          pullMe.addOrLoadBestPlanMapping(false, this);


        /* Mark current join position as unused */
        proposedJoinOrder[joinPosition] = -1;
      }

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Examples of org.apache.derby.iapi.sql.compile.Optimizable.addOrLoadBestPlanMapping()

      Optimizable pullMe =
        optimizableList.getOptimizable(
                  proposedJoinOrder[joinPosition]);
      pullMe.pullOptPredicates(predicateList);
      if (reloadBestPlan)
        pullMe.addOrLoadBestPlanMapping(false, this);
      proposedJoinOrder[joinPosition] = -1;
      if (joinPosition == 0) break;
    }
    currentCost.setCost(0.0d, 0.0d, 0.0d);
    currentSortAvoidanceCost.setCost(0.0d, 0.0d, 0.0d);

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Examples of org.apache.derby.iapi.sql.compile.Optimizable.addOrLoadBestPlanMapping()

      // then we know that the most recent access path (represented
      // by "current" access path) was not the best.
      if (curOpt.getBestAccessPath().getCostEstimate().compare(
        curOpt.getCurrentAccessPath().getCostEstimate()) != 0)
      {
        curOpt.addOrLoadBestPlanMapping(false, curOpt);
      }
      else if (curOpt.getBestAccessPath().getCostEstimate().rowCount() <
        curOpt.getCurrentAccessPath().getCostEstimate().rowCount())
      {
        // If currentCost and bestCost have the same cost estimate

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Examples of org.apache.derby.iapi.sql.compile.Optimizable.addOrLoadBestPlanMapping()

        // If currentCost and bestCost have the same cost estimate
        // but currentCost has been rejected because of memory, we
        // still need to revert the plans.  In this case the row
        // count for currentCost will be greater than the row count
        // for bestCost, so that's what we just checked.
        curOpt.addOrLoadBestPlanMapping(false, curOpt);
      }
    }


    /*
    ** When all the access paths have been looked at, we know what the

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