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* This library is free software; you can redistribute it and/or
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* Lesser General Public License for more details.
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package org.teiid.query.optimizer.relational.rules;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
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.PlanNode;
import org.teiid.query.optimizer.relational.plantree.NodeConstants.Info;
import org.teiid.query.sql.lang.JoinType;
import org.teiid.query.sql.lang.OrderBy;
import org.teiid.query.sql.lang.OrderByItem;
import org.teiid.query.sql.symbol.ElementSymbol;
import org.teiid.query.sql.symbol.Expression;
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.ElementCollectorVisitor;
import org.teiid.query.sql.visitor.FunctionCollectorVisitor;
import org.teiid.query.sql.visitor.GroupsUsedByElementsVisitor;
import org.teiid.query.sql.visitor.ValueIteratorProviderCollectorVisitor;
import org.teiid.query.util.CommandContext;
public final class RuleMergeVirtual implements
OptimizerRule {
public PlanNode execute(PlanNode plan,
QueryMetadataInterface metadata,
CapabilitiesFinder capFinder,
RuleStack rules,
AnalysisRecord analysisRecord,
CommandContext context) throws QueryPlannerException,
QueryMetadataException,
TeiidComponentException {
boolean beforeDecomposeJoin = rules.contains(RuleConstants.DECOMPOSE_JOIN);
for (PlanNode sourceNode : NodeEditor.findAllNodes(plan, NodeConstants.Types.SOURCE)) {
if (sourceNode.getChildCount() > 0) {
plan = doMerge(sourceNode, plan, beforeDecomposeJoin, metadata);
}
}
return plan;
}
static PlanNode doMerge(PlanNode frame,
PlanNode root, boolean beforeDecomposeJoin,
QueryMetadataInterface metadata) throws QueryPlannerException, QueryMetadataException, TeiidComponentException {
GroupSymbol virtualGroup = frame.getGroups().iterator().next();
// check to see if frame represents a proc relational query.
if (virtualGroup.isProcedure()) {
return root;
}
SymbolMap references = (SymbolMap)frame.getProperty(NodeConstants.Info.CORRELATED_REFERENCES);
if (references != null) {
return root; //correlated nested table commands should not be merged
}
PlanNode parentProject = NodeEditor.findParent(frame, NodeConstants.Types.PROJECT);
// Check whether the upper frame is a SELECT INTO
if (parentProject.getProperty(NodeConstants.Info.INTO_GROUP) != null) {
return root;
}
if (!FrameUtil.canConvertAccessPatterns(frame)) {
return root;
}
PlanNode projectNode = frame.getFirstChild();
// Check if lower frame has only a stored procedure execution - this cannot be merged to parent frame
if (FrameUtil.isProcedure(projectNode)) {
return root;
}
SymbolMap symbolMap = (SymbolMap)frame.getProperty(NodeConstants.Info.SYMBOL_MAP);
PlanNode sortNode = NodeEditor.findParent(parentProject, NodeConstants.Types.SORT, NodeConstants.Types.SOURCE);
if (sortNode != null && sortNode.hasBooleanProperty(NodeConstants.Info.UNRELATED_SORT)) {
OrderBy sortOrder = (OrderBy)sortNode.getProperty(NodeConstants.Info.SORT_ORDER);
boolean unrelated = false;
for (OrderByItem item : sortOrder.getOrderByItems()) {
if (!item.isUnrelated()) {
continue;
}
Collection<ElementSymbol> elements = ElementCollectorVisitor.getElements(item.getSymbol(), true);
for (ElementSymbol elementSymbol : elements) {
if (virtualGroup.equals(elementSymbol.getGroupSymbol())) {
unrelated = true;
if (!(symbolMap.getMappedExpression(elementSymbol) instanceof ElementSymbol)) {
return root;
}
}
}
}
// the lower frame cannot contain DUP_REMOVE, GROUP, UNION if unrelated
if (unrelated && NodeEditor.findNodePreOrder(frame, NodeConstants.Types.DUP_REMOVE, NodeConstants.Types.PROJECT) != null
|| NodeEditor.findNodePreOrder(frame, NodeConstants.Types.SET_OP, NodeConstants.Types.SOURCE) != null
|| NodeEditor.findNodePreOrder(frame, NodeConstants.Types.GROUP, NodeConstants.Types.SOURCE) != null) {
return root;
}
}
//try to remove the virtual layer if we are only doing a simple projection in the following cases:
// 1. if the frame root is something other than a project (SET_OP, SORT, LIMIT, etc.)
// 2. if the frame has a grouping node
// 3. if the frame has no sources
if (projectNode.getType() != NodeConstants.Types.PROJECT
|| NodeEditor.findNodePreOrder(frame.getFirstChild(), NodeConstants.Types.GROUP, NodeConstants.Types.SOURCE
| NodeConstants.Types.JOIN) != null
|| NodeEditor.findAllNodes(frame.getFirstChild(), NodeConstants.Types.SOURCE, NodeConstants.Types.SOURCE).isEmpty()) {
PlanNode parentSource = NodeEditor.findParent(parentProject, NodeConstants.Types.SOURCE);
if (beforeDecomposeJoin && parentSource != null && parentSource.hasProperty(Info.PARTITION_INFO)
&& !NodeEditor.findAllNodes(frame.getFirstChild(), NodeConstants.Types.SET_OP, NodeConstants.Types.SOURCE).isEmpty()) {
return root; //don't bother to merge until after
}
return checkForSimpleProjection(frame, root, parentProject, metadata);
}
PlanNode parentJoin = NodeEditor.findParent(frame, NodeConstants.Types.JOIN, NodeConstants.Types.SOURCE);
if (!checkJoinCriteria(frame, virtualGroup, parentJoin)) {
return root;
}
PlanNode parentGroup = NodeEditor.findParent(frame, NodeConstants.Types.GROUP, NodeConstants.Types.SOURCE);
List<SingleElementSymbol> groupCols = null;
if (parentGroup != null) {
groupCols = (List<SingleElementSymbol>)parentGroup.getProperty(NodeConstants.Info.GROUP_COLS);
}
if (!checkProjectedSymbols(projectNode, virtualGroup, parentJoin, groupCols, symbolMap, metadata)) {
return root;
}
// Otherwise merge should work
// Convert parent frame before merge
FrameUtil.convertFrame(frame, virtualGroup, FrameUtil.findJoinSourceNode(projectNode).getGroups(), symbolMap.asMap(), metadata);
PlanNode parentBottom = frame.getParent();
prepareFrame(frame);
// Remove top 2 nodes (SOURCE, PROJECT) of virtual group - they're no longer needed
NodeEditor.removeChildNode(parentBottom, frame);
NodeEditor.removeChildNode(parentBottom, projectNode);
return root;
}
private static void prepareFrame(PlanNode frame) {
// find the new root of the frame so that access patterns can be propagated
PlanNode newRoot = FrameUtil.findJoinSourceNode(frame.getFirstChild());
if (newRoot != null) {
Collection ap = (Collection)frame.getProperty(NodeConstants.Info.ACCESS_PATTERNS);
if (ap != null) {
Collection newAp = (Collection)newRoot.getProperty(NodeConstants.Info.ACCESS_PATTERNS);
if (newAp == null) {
newRoot.setProperty(NodeConstants.Info.ACCESS_PATTERNS, ap);
} else {
newAp.addAll(ap);
}
}
RulePlaceAccess.copyDependentHints(frame, newRoot);
}
}
/**
* Removes source layers that only do a simple projection of the elements below.
* @throws TeiidComponentException
* @throws QueryMetadataException
*/
private static PlanNode checkForSimpleProjection(PlanNode frame,
PlanNode root,
PlanNode parentProject,
QueryMetadataInterface metadata) throws QueryMetadataException, TeiidComponentException {
// check that the parent only performs projection
PlanNode nodeToCheck = parentProject.getFirstChild();
while (nodeToCheck != frame) {
if (nodeToCheck.getType() != NodeConstants.Types.SELECT
|| !nodeToCheck.hasBooleanProperty(NodeConstants.Info.IS_PHANTOM)) {
return root;
}
nodeToCheck = nodeToCheck.getFirstChild();
}
if (frame.getFirstChild().getType() == NodeConstants.Types.TUPLE_LIMIT
&& NodeEditor.findParent(parentProject,
NodeConstants.Types.SORT | NodeConstants.Types.DUP_REMOVE,
NodeConstants.Types.SOURCE | NodeConstants.Types.SET_OP) != null) {
return root;
}
List<? extends SingleElementSymbol> requiredElements = RuleAssignOutputElements.determineSourceOutput(frame, new ArrayList<SingleElementSymbol>(), metadata, null);
List<SingleElementSymbol> selectSymbols = (List<SingleElementSymbol>)parentProject.getProperty(NodeConstants.Info.PROJECT_COLS);
// check that it only performs simple projection and that all required symbols are projected
LinkedHashSet<ElementSymbol> symbols = new LinkedHashSet<ElementSymbol>(); //ensuring there are no duplicates prevents problems with subqueries
for (SingleElementSymbol symbol : selectSymbols) {
Expression expr = SymbolMap.getExpression(symbol);
if (!(expr instanceof ElementSymbol)) {
return root;
}
requiredElements.remove(expr);
if (!symbols.add((ElementSymbol)expr)) {
return root;
}
}
if (!requiredElements.isEmpty()) {
return root;
}
// re-order the lower projects
RuleAssignOutputElements.filterVirtualElements(frame, new ArrayList<SingleElementSymbol>(symbols), metadata);
// remove phantom select nodes
nodeToCheck = parentProject.getFirstChild();
while (nodeToCheck != frame) {
PlanNode current = nodeToCheck;
nodeToCheck = nodeToCheck.getFirstChild();
NodeEditor.removeChildNode(current.getParent(), current);
}
if (NodeEditor.findParent(parentProject, NodeConstants.Types.DUP_REMOVE, NodeConstants.Types.SOURCE) != null) {
PlanNode lowerDup = NodeEditor.findNodePreOrder(frame.getFirstChild(), NodeConstants.Types.DUP_REMOVE, NodeConstants.Types.PROJECT);
if (lowerDup != null) {
NodeEditor.removeChildNode(lowerDup.getParent(), lowerDup);
}
PlanNode setOp = NodeEditor.findNodePreOrder(frame.getFirstChild(), NodeConstants.Types.SET_OP, NodeConstants.Types.SOURCE);
if (setOp != null) {
setOp.setProperty(NodeConstants.Info.USE_ALL, Boolean.FALSE);
if (parentProject.getParent().getParent() != null) {
NodeEditor.removeChildNode(parentProject.getParent().getParent(), parentProject.getParent());
} else {
parentProject.removeFromParent();
root = parentProject;
}
}
}
correctOrderBy(frame, selectSymbols, parentProject);
PlanNode parentSource = NodeEditor.findParent(frame, NodeConstants.Types.SOURCE);
PlanNode parentSetOp = NodeEditor.findParent(parentProject, NodeConstants.Types.SET_OP, NodeConstants.Types.SOURCE);
if (parentSetOp == null || NodeEditor.findNodePreOrder(parentSetOp, NodeConstants.Types.PROJECT) == parentProject) {
if (parentSource != null) {
FrameUtil.correctSymbolMap(((SymbolMap)frame.getProperty(NodeConstants.Info.SYMBOL_MAP)).asMap(), parentSource);
}
if (parentSetOp != null) {
correctOrderBy(frame, selectSymbols, parentSetOp);
}
}
prepareFrame(frame);
//remove the parent project and the source node
NodeEditor.removeChildNode(parentProject, frame);
if (parentProject.getParent() == null) {
root = parentProject.getFirstChild();
parentProject.removeChild(root);
return root;
}
NodeEditor.removeChildNode(parentProject.getParent(), parentProject);
return root;
}
private static void correctOrderBy(PlanNode frame,
List<SingleElementSymbol> selectSymbols, PlanNode startNode) {
PlanNode sort = NodeEditor.findParent(startNode, NodeConstants.Types.SORT, NodeConstants.Types.SOURCE | NodeConstants.Types.SET_OP);
if (sort != null) { //special handling is needed since we are retaining the child aliases
List<SingleElementSymbol> childProject = (List<SingleElementSymbol>)NodeEditor.findNodePreOrder(frame, NodeConstants.Types.PROJECT).getProperty(NodeConstants.Info.PROJECT_COLS);
OrderBy elements = (OrderBy)sort.getProperty(NodeConstants.Info.SORT_ORDER);
for (OrderByItem item : elements.getOrderByItems()) {
item.setSymbol(childProject.get(selectSymbols.indexOf(item.getSymbol())));
}
sort.getGroups().clear();
sort.addGroups(GroupsUsedByElementsVisitor.getGroups(elements));
}
}
/**
* Check to ensure that we are not projecting a subquery or null dependent expressions
*/
private static boolean checkProjectedSymbols(PlanNode projectNode,
GroupSymbol virtualGroup,
PlanNode parentJoin,
List<SingleElementSymbol> parentGroupingCols,
SymbolMap symbolMap,
QueryMetadataInterface metadata) {
List<SingleElementSymbol> selectSymbols = (List<SingleElementSymbol>)projectNode.getProperty(NodeConstants.Info.PROJECT_COLS);
HashSet<GroupSymbol> groups = new HashSet<GroupSymbol>();
for (PlanNode sourceNode : NodeEditor.findAllNodes(projectNode, NodeConstants.Types.SOURCE, NodeConstants.Types.SOURCE)) {
groups.addAll(sourceNode.getGroups());
}
boolean checkForNullDependent = false;
// check to see if there are projected literal on the inner side of an outer join that needs to be preserved
if (parentJoin != null) {
PlanNode joinToTest = parentJoin;
while (joinToTest != null) {
JoinType joinType = (JoinType)joinToTest.getProperty(NodeConstants.Info.JOIN_TYPE);
if (joinType == JoinType.JOIN_FULL_OUTER) {
checkForNullDependent = true;
break;
} else if (joinType == JoinType.JOIN_LEFT_OUTER
&& FrameUtil.findJoinSourceNode(joinToTest.getLastChild()).getGroups().contains(virtualGroup)) {
checkForNullDependent = true;
break;
}
joinToTest = NodeEditor.findParent(joinToTest.getParent(), NodeConstants.Types.JOIN, NodeConstants.Types.SOURCE);
}
}
List<ElementSymbol> virtualElements = symbolMap.getKeys();
for (int i = 0; i < selectSymbols.size(); i++) {
SingleElementSymbol symbol = selectSymbols.get(i);
Collection scalarSubqueries = ValueIteratorProviderCollectorVisitor.getValueIteratorProviders(symbol);
if (!scalarSubqueries.isEmpty()) {
return false;
}
if (checkForNullDependent && JoinUtil.isNullDependent(metadata, groups, SymbolMap.getExpression(symbol))) {
return false;
}
if (parentGroupingCols != null && !(SymbolMap.getExpression(symbol) instanceof SingleElementSymbol) && parentGroupingCols.contains(virtualElements.get(i))) {
return false;
}
// TEIID-16: We do not want to merge a non-deterministic scalar function
if (FunctionCollectorVisitor.isNonDeterministic(symbol)) {
return false;
}
}
return true;
}
/**
* check to see if criteria is used in a full outer join or has no groups and is on the inner side of an outer join. if this
* is the case then the layers cannot be merged, since merging would possibly force the criteria to change it's position (into
* the on clause or above the join).
*/
private static boolean checkJoinCriteria(PlanNode frame,
GroupSymbol virtualGroup,
PlanNode parentJoin) {
if (parentJoin != null) {
List<PlanNode> selectNodes = NodeEditor.findAllNodes(frame.getFirstChild(),
NodeConstants.Types.SELECT,
NodeConstants.Types.SOURCE);
Set<GroupSymbol> groups = new HashSet<GroupSymbol>();
groups.add(virtualGroup);
for (PlanNode selectNode : selectNodes) {
if (selectNode.hasBooleanProperty(NodeConstants.Info.IS_PHANTOM)) {
continue;
}
JoinType jt = JoinUtil.getJoinTypePreventingCriteriaOptimization(parentJoin, groups);
if (jt != null && (jt == JoinType.JOIN_FULL_OUTER || selectNode.getGroups().size() == 0)) {
return false;
}
}
}
return true;
}
public String toString() {
return "MergeVirtual"; //$NON-NLS-1$
}
}