Package org.teiid.query.optimizer.relational.rules

Source Code of org.teiid.query.optimizer.relational.rules.RuleImplementJoinStrategy

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package org.teiid.query.optimizer.relational.rules;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.teiid.api.exception.query.QueryMetadataException;
import org.teiid.api.exception.query.QueryPlannerException;
import org.teiid.core.TeiidComponentException;
import org.teiid.query.analysis.AnalysisRecord;
import org.teiid.query.metadata.QueryMetadataInterface;
import org.teiid.query.optimizer.capabilities.CapabilitiesFinder;
import org.teiid.query.optimizer.relational.OptimizerRule;
import org.teiid.query.optimizer.relational.RuleStack;
import org.teiid.query.optimizer.relational.plantree.NodeConstants;
import org.teiid.query.optimizer.relational.plantree.NodeEditor;
import org.teiid.query.optimizer.relational.plantree.NodeFactory;
import org.teiid.query.optimizer.relational.plantree.PlanNode;
import org.teiid.query.optimizer.relational.plantree.NodeConstants.Info;
import org.teiid.query.processor.relational.RelationalNode;
import org.teiid.query.processor.relational.JoinNode.JoinStrategyType;
import org.teiid.query.processor.relational.MergeJoinStrategy.SortOption;
import org.teiid.query.sql.lang.CompareCriteria;
import org.teiid.query.sql.lang.Criteria;
import org.teiid.query.sql.lang.JoinType;
import org.teiid.query.sql.lang.OrderBy;
import org.teiid.query.sql.symbol.ElementSymbol;
import org.teiid.query.sql.symbol.GroupSymbol;
import org.teiid.query.sql.symbol.SingleElementSymbol;
import org.teiid.query.sql.util.SymbolMap;
import org.teiid.query.sql.visitor.GroupsUsedByElementsVisitor;
import org.teiid.query.util.CommandContext;


/**
* Inserts sort nodes for specific join strategies.
*/
public class RuleImplementJoinStrategy implements OptimizerRule {
       
    /**
     * @see org.teiid.query.optimizer.relational.OptimizerRule#execute(org.teiid.query.optimizer.relational.plantree.PlanNode, org.teiid.query.metadata.QueryMetadataInterface, org.teiid.query.optimizer.capabilities.CapabilitiesFinder, org.teiid.query.optimizer.relational.RuleStack, org.teiid.query.analysis.AnalysisRecord, org.teiid.query.util.CommandContext)
     */
    public PlanNode execute(PlanNode plan,
                            QueryMetadataInterface metadata,
                            CapabilitiesFinder capabilitiesFinder,
                            RuleStack rules,
                            AnalysisRecord analysisRecord,
                            CommandContext context) throws QueryPlannerException,
                                                   QueryMetadataException,
                                                   TeiidComponentException {
     
      for (PlanNode sourceNode : NodeEditor.findAllNodes(plan, NodeConstants.Types.SOURCE, NodeConstants.Types.ACCESS)) {
        SymbolMap references = (SymbolMap)sourceNode.getProperty(NodeConstants.Info.CORRELATED_REFERENCES);
          if (references != null) {
            Set<GroupSymbol> groups = GroupsUsedByElementsVisitor.getGroups(references.getValues());
            PlanNode joinNode = NodeEditor.findParent(sourceNode, NodeConstants.Types.JOIN, NodeConstants.Types.SOURCE);
            while (joinNode != null) {
              joinNode.setProperty(NodeConstants.Info.JOIN_STRATEGY, JoinStrategyType.NESTED_TABLE);
              if (joinNode.getProperty(NodeConstants.Info.DEPENDENT_VALUE_SOURCE) != null) {
                //sanity check
                throw new AssertionError("Cannot use a depenedent join when the join involves a correlated nested table.")//$NON-NLS-1$
              }
              if (joinNode.getGroups().containsAll(groups)) {
                break;
              }
              joinNode = NodeEditor.findParent(joinNode, NodeConstants.Types.JOIN, NodeConstants.Types.SOURCE);
            }
          }
      }

        for (PlanNode joinNode : NodeEditor.findAllNodes(plan, NodeConstants.Types.JOIN, NodeConstants.Types.ACCESS)) {
            JoinStrategyType stype = (JoinStrategyType) joinNode.getProperty(NodeConstants.Info.JOIN_STRATEGY);
            if (!JoinStrategyType.MERGE.equals(stype)) {
              continue;
            }
           
            /**
             * Don't push sorts for unbalanced inner joins, we prefer to use a processing time cost based decision
             */
            boolean pushLeft = true;
            boolean pushRight = true;
            if (joinNode.getProperty(NodeConstants.Info.JOIN_TYPE) == JoinType.JOIN_INNER && context != null) {
              float leftCost = NewCalculateCostUtil.computeCostForTree(joinNode.getFirstChild(), metadata);
              float rightCost = NewCalculateCostUtil.computeCostForTree(joinNode.getLastChild(), metadata);
              if (leftCost != NewCalculateCostUtil.UNKNOWN_VALUE && rightCost != NewCalculateCostUtil.UNKNOWN_VALUE
                  && (leftCost > context.getProcessorBatchSize() || rightCost > context.getProcessorBatchSize())) {
                //we use a larger constant here to ensure that we don't unwisely prevent pushdown
                pushLeft = leftCost < context.getProcessorBatchSize() || leftCost / rightCost < 8;
                pushRight = rightCost < context.getProcessorBatchSize() || rightCost / leftCost < 8 || joinNode.getProperty(NodeConstants.Info.DEPENDENT_VALUE_SOURCE) != null;
              }
            }

            List<SingleElementSymbol> leftExpressions = (List<SingleElementSymbol>) joinNode.getProperty(NodeConstants.Info.LEFT_EXPRESSIONS);
            List<SingleElementSymbol> rightExpressions = (List<SingleElementSymbol>) joinNode.getProperty(NodeConstants.Info.RIGHT_EXPRESSIONS);

            //check index information on each side
            //TODO: don't do null order compensation - in fact we should check what the order actually is, but we don't have that metadata
            Object key = null;
            boolean right = true;
            //we check the right first, since it should be larger
            if (joinNode.getLastChild().getType() == NodeConstants.Types.ACCESS && NewCalculateCostUtil.isSingleTable(joinNode.getLastChild())) {
              key = NewCalculateCostUtil.getKeyUsed(rightExpressions, null, metadata, null);
            }
            if (key == null && joinNode.getFirstChild().getType() == NodeConstants.Types.ACCESS && NewCalculateCostUtil.isSingleTable(joinNode.getFirstChild())) {
              key = NewCalculateCostUtil.getKeyUsed(leftExpressions, null, metadata, null);
              right = false;
            }
            if (key != null) {
              //redo the join predicates based upon the key alone
              List<Object> keyCols = metadata.getElementIDsInKey(key);
              int[] reorder = new int[keyCols.size()];
              List<Integer> toCriteria = new ArrayList<Integer>(rightExpressions.size() - keyCols.size());
              List<SingleElementSymbol> keyExpressions = right?rightExpressions:leftExpressions;
            for (int j = 0; j < keyExpressions.size(); j++) {
          SingleElementSymbol ses = keyExpressions.get(j);
          if (!(ses instanceof ElementSymbol)) {
            continue;
          }
          ElementSymbol es = (ElementSymbol)ses;
          boolean found = false;
          for (int i = 0; !found && i < keyCols.size(); i++) {
            if (es.getMetadataID().equals(keyCols.get(i))) {
              reorder[i] = j;
              found = true;
            }
          }
          if (!found) {
            toCriteria.add(j);
          }
        }
            List<Criteria> joinCriteria = (List<Criteria>) joinNode.getProperty(Info.JOIN_CRITERIA);
            for (int index : toCriteria) {
          SingleElementSymbol lses = leftExpressions.get(index);
          SingleElementSymbol rses = rightExpressions.get(index);
          CompareCriteria cc = new CompareCriteria(lses, CompareCriteria.EQ, rses);
          if (joinCriteria == null || joinCriteria.isEmpty()) {
            joinCriteria = new ArrayList<Criteria>();
            joinCriteria.add(cc);
            joinNode.setProperty(Info.JOIN_TYPE, JoinType.JOIN_INNER);
          }
        }
            joinNode.setProperty(Info.JOIN_CRITERIA, joinCriteria);
            leftExpressions = RelationalNode.projectTuple(reorder, leftExpressions);
              rightExpressions = RelationalNode.projectTuple(reorder, rightExpressions);
              joinNode.setProperty(NodeConstants.Info.LEFT_EXPRESSIONS, leftExpressions);
              joinNode.setProperty(NodeConstants.Info.RIGHT_EXPRESSIONS, rightExpressions);
            }
           
      boolean pushedLeft = insertSort(joinNode.getFirstChild(), leftExpressions, joinNode, metadata, capabilitiesFinder, pushLeft)
      insertSort(joinNode.getLastChild(), rightExpressions, joinNode, metadata, capabilitiesFinder, pushRight);
         
          if (joinNode.getProperty(NodeConstants.Info.JOIN_TYPE) == JoinType.JOIN_INNER && (!pushRight || !pushedLeft)) {
            joinNode.setProperty(NodeConstants.Info.JOIN_STRATEGY, JoinStrategyType.ENHANCED_SORT);
          }
        }
       
        return plan;
    }

    /**
     * Insert a sort node under the merge join node.  If necessary, also insert a project
     * node to handle function evaluation. 
     * @param expressions The expressions that need to be sorted on
     * @param jnode The planner merge join node to attach to
     * @return returns true if a project node needs added
     * @throws TeiidComponentException
     * @throws QueryMetadataException
     */
    static boolean insertSort(PlanNode childNode, List<SingleElementSymbol> expressions, PlanNode jnode, QueryMetadataInterface metadata, CapabilitiesFinder capFinder,
        boolean attemptPush) throws QueryMetadataException, TeiidComponentException {
        Set<SingleElementSymbol> orderSymbols = new LinkedHashSet<SingleElementSymbol>(expressions);

        PlanNode sourceNode = FrameUtil.findJoinSourceNode(childNode);
        PlanNode joinNode = childNode.getParent();

        Set<SingleElementSymbol> outputSymbols = new LinkedHashSet<SingleElementSymbol>((List<SingleElementSymbol>)childNode.getProperty(NodeConstants.Info.OUTPUT_COLS));
       
        int oldSize = outputSymbols.size();
       
        outputSymbols.addAll(expressions);
       
        boolean needsCorrection = outputSymbols.size() > oldSize;
               
        PlanNode sortNode = createSortNode(new ArrayList<SingleElementSymbol>(orderSymbols), outputSymbols);
       
        if (sourceNode.getType() == NodeConstants.Types.ACCESS) {
          if (NewCalculateCostUtil.usesKey(sourceNode, expressions, metadata)) {
                joinNode.setProperty(joinNode.getFirstChild() == childNode ? NodeConstants.Info.IS_LEFT_DISTINCT : NodeConstants.Info.IS_RIGHT_DISTINCT, true);
          }
          if (attemptPush && RuleRaiseAccess.canRaiseOverSort(sourceNode, metadata, capFinder, sortNode, null, false)) {
              sourceNode.getFirstChild().addAsParent(sortNode);
             
              if (needsCorrection) {
                  correctOutputElements(joinNode, outputSymbols, sortNode);
              }
              return true;
          }
        }
       
        joinNode.setProperty(joinNode.getFirstChild() == childNode ? NodeConstants.Info.SORT_LEFT : NodeConstants.Info.SORT_RIGHT, SortOption.SORT);
       
        if (needsCorrection) {
            PlanNode projectNode = NodeFactory.getNewNode(NodeConstants.Types.PROJECT);
            projectNode.setProperty(NodeConstants.Info.PROJECT_COLS, new ArrayList(outputSymbols));
            childNode.addAsParent(projectNode);
            correctOutputElements(joinNode, outputSymbols, projectNode);
        }       
        return false;
    }

    private static PlanNode createSortNode(List<SingleElementSymbol> orderSymbols,
                                           Collection outputElements) {
        PlanNode sortNode = NodeFactory.getNewNode(NodeConstants.Types.SORT);
        sortNode.setProperty(NodeConstants.Info.SORT_ORDER, new OrderBy(orderSymbols));
        sortNode.setProperty(NodeConstants.Info.OUTPUT_COLS, new ArrayList(outputElements));
        return sortNode;
    }

    private static void correctOutputElements(PlanNode endNode,
                                              Collection outputElements,
                                              PlanNode startNode) {
        while (startNode != endNode) {
            startNode.setProperty(NodeConstants.Info.OUTPUT_COLS, new ArrayList(outputElements));
            startNode = startNode.getParent();
        }
    }
           
    /**
     * @see java.lang.Object#toString()
     */
    public String toString() {
        return "ImplementJoinStrategy"; //$NON-NLS-1$
    }

}
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