simpledb.opt
Class HeuristicQueryPlanner

java.lang.Object
  simpledb.opt.HeuristicQueryPlanner

All Implemented Interfaces:

QueryPlanner

public class HeuristicQueryPlanner
extends Object
implements QueryPlanner

A query planner that optimizes using a heuristic-based algorithm.

Author:

Edward Sciore

Constructor Summary

HeuristicQueryPlanner()

Method Summary

Plan	createPlan(QueryData data, Transaction tx) Creates an optimized left-deep query plan using the following heuristics.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HeuristicQueryPlanner

public HeuristicQueryPlanner()

Method Detail

createPlan

public Plan createPlan(QueryData data,
                       Transaction tx)

Creates an optimized left-deep query plan using the following heuristics. H1. Choose the smallest table (considering selection predicates) to be first in the join order. H2. Add the table to the join order which results in the smallest output.

Specified by:

createPlan in interface QueryPlanner

Parameters:

data - the parsed representation of the query

tx - the calling transaction

Returns:

a plan for that query