Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Map / ViewGeneration / QueryRewriting / RewritingPass.cs / 1305376 / RewritingPass.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] // @backupOwner [....] //--------------------------------------------------------------------- using System; using System.Diagnostics; using System.Collections.Generic; using System.Text; using System.Linq; namespace System.Data.Mapping.ViewGeneration.QueryRewriting { // Goal: use the next view to get rewritingSoFar to be closer to the goal internal class RewritingPasswhere T_Tile : class { // region that rewriting needs to cover private readonly T_Tile m_toFill; // region that rewriting needs to be disjoint with private readonly T_Tile m_toAvoid; private readonly List m_views; private readonly RewritingProcessor m_qp; private readonly Dictionary m_usedViews = new Dictionary (); public RewritingPass(T_Tile toFill, T_Tile toAvoid, List views, RewritingProcessor qp) { m_toFill = toFill; m_toAvoid = toAvoid; m_views = views; m_qp = qp; } public static bool RewriteQuery(T_Tile toFill, T_Tile toAvoid, out T_Tile rewriting, List views, RewritingProcessor qp) { RewritingPass rewritingPass = new RewritingPass (toFill, toAvoid, views, qp); if (rewritingPass.RewriteQuery(out rewriting)) { RewritingSimplifier .TrySimplifyUnionRewriting(ref rewriting, toFill, toAvoid, qp); return true; } return false; } private static bool RewriteQueryInternal(T_Tile toFill, T_Tile toAvoid, out T_Tile rewriting, List views, HashSet recentlyUsedViews, RewritingProcessor qp) { if (qp.REORDER_VIEWS && recentlyUsedViews.Count > 0) { // move recently used views toward the end List reorderedViews = new List (); foreach (T_Tile view in views) { if (false == recentlyUsedViews.Contains(view)) { reorderedViews.Add(view); } } reorderedViews.AddRange(recentlyUsedViews); views = reorderedViews; } RewritingPass rewritingPass = new RewritingPass (toFill, toAvoid, views, qp); return rewritingPass.RewriteQuery(out rewriting); } private bool RewriteQuery(out T_Tile rewriting) { rewriting = m_toFill; T_Tile rewritingSoFar; if (false == FindRewritingByIncludedAndDisjoint(out rewritingSoFar)) { if (false == FindContributingView(out rewritingSoFar)) { return false; } } bool hasExtraTuples = !m_qp.IsDisjointFrom(rewritingSoFar, m_toAvoid); // try to cut off extra tuples using joins if (hasExtraTuples) { foreach (T_Tile view in AvailableViews) { if (TryJoin(view, ref rewritingSoFar)) { hasExtraTuples = false; break; } } } // try to cut off extra tuples using anti-semijoins if (hasExtraTuples) { foreach (T_Tile view in AvailableViews) { if (TryAntiSemiJoin(view, ref rewritingSoFar)) { hasExtraTuples = false; break; } } } if (hasExtraTuples) { return false; // won't be able to cut off extra tuples } // remove redundant joins and anti-semijoins RewritingSimplifier .TrySimplifyJoinRewriting(ref rewritingSoFar, m_toAvoid, m_usedViews, m_qp); // find rewriting for missing tuples, if any T_Tile missingTuples = m_qp.AntiSemiJoin(m_toFill, rewritingSoFar); if (!m_qp.IsEmpty(missingTuples)) { T_Tile rewritingForMissingTuples; if (false == RewritingPass .RewriteQueryInternal(missingTuples, m_toAvoid, out rewritingForMissingTuples, m_views, new HashSet (m_usedViews.Keys), m_qp)) { rewriting = rewritingForMissingTuples; return false; // failure } else { // Although a more general optimization for UNIONs will handle this case, // adding this check reduces the overall number of containment tests if (m_qp.IsContainedIn(rewritingSoFar, rewritingForMissingTuples)) { rewritingSoFar = rewritingForMissingTuples; } else { rewritingSoFar = m_qp.Union(rewritingSoFar, rewritingForMissingTuples); } } } // if we reached this point, we have a successful rewriting rewriting = rewritingSoFar; return true; } // returns true if no more extra tuples are left private bool TryJoin(T_Tile view, ref T_Tile rewriting) { T_Tile newRewriting = m_qp.Join(rewriting, view); if (!m_qp.IsEmpty(newRewriting)) { m_usedViews[view] = TileOpKind.Join; rewriting = newRewriting; return m_qp.IsDisjointFrom(rewriting, m_toAvoid); } return false; } // returns true if no more extra tuples are left private bool TryAntiSemiJoin(T_Tile view, ref T_Tile rewriting) { T_Tile newRewriting = m_qp.AntiSemiJoin(rewriting, view); if (!m_qp.IsEmpty(newRewriting)) { m_usedViews[view] = TileOpKind.AntiSemiJoin; rewriting = newRewriting; return m_qp.IsDisjointFrom(rewriting, m_toAvoid); } return false; } // Try to find a rewriting by intersecting all views which contain the query // and subtracting all views that are disjoint from the query private bool FindRewritingByIncludedAndDisjoint(out T_Tile rewritingSoFar) { // intersect all views in which m_toFill is contained rewritingSoFar = null; foreach (T_Tile view in AvailableViews) { if (m_qp.IsContainedIn(m_toFill, view)) // query <= view { if (rewritingSoFar == null) { rewritingSoFar = view; m_usedViews[view] = TileOpKind.Join; } else { T_Tile newRewriting = m_qp.Join(rewritingSoFar, view); if (!m_qp.IsContainedIn(rewritingSoFar, newRewriting)) { rewritingSoFar = newRewriting; m_usedViews[view] = TileOpKind.Join; // it is a useful join } else { continue; // useless join } } if (m_qp.IsContainedIn(rewritingSoFar, m_toFill)) { return true; } } } // subtract all views that are disjoint from m_toFill if (rewritingSoFar != null) { foreach (T_Tile view in AvailableViews) { if (m_qp.IsDisjointFrom(m_toFill, view)) // query ^ view = {} { if (!m_qp.IsDisjointFrom(rewritingSoFar, view)) { rewritingSoFar = m_qp.AntiSemiJoin(rewritingSoFar, view); m_usedViews[view] = TileOpKind.AntiSemiJoin; if (m_qp.IsContainedIn(rewritingSoFar, m_toFill)) { return true; } } } } } return rewritingSoFar != null; } private bool FindContributingView(out T_Tile rewriting) { // find some view that helps reduce toFill foreach (T_Tile view in AvailableViews) { if (false == m_qp.IsDisjointFrom(view, m_toFill)) { rewriting = view; m_usedViews[view] = TileOpKind.Join; // positive, intersected return true; } } rewriting = null; return false; } private IEnumerable AvailableViews { get { return m_views.Where(view => !m_usedViews.ContainsKey(view)); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //---------------------------------------------------------------------- // // Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] // @backupOwner [....] //--------------------------------------------------------------------- using System; using System.Diagnostics; using System.Collections.Generic; using System.Text; using System.Linq; namespace System.Data.Mapping.ViewGeneration.QueryRewriting { // Goal: use the next view to get rewritingSoFar to be closer to the goal internal class RewritingPasswhere T_Tile : class { // region that rewriting needs to cover private readonly T_Tile m_toFill; // region that rewriting needs to be disjoint with private readonly T_Tile m_toAvoid; private readonly List m_views; private readonly RewritingProcessor m_qp; private readonly Dictionary m_usedViews = new Dictionary (); public RewritingPass(T_Tile toFill, T_Tile toAvoid, List views, RewritingProcessor qp) { m_toFill = toFill; m_toAvoid = toAvoid; m_views = views; m_qp = qp; } public static bool RewriteQuery(T_Tile toFill, T_Tile toAvoid, out T_Tile rewriting, List views, RewritingProcessor qp) { RewritingPass rewritingPass = new RewritingPass (toFill, toAvoid, views, qp); if (rewritingPass.RewriteQuery(out rewriting)) { RewritingSimplifier .TrySimplifyUnionRewriting(ref rewriting, toFill, toAvoid, qp); return true; } return false; } private static bool RewriteQueryInternal(T_Tile toFill, T_Tile toAvoid, out T_Tile rewriting, List views, HashSet recentlyUsedViews, RewritingProcessor qp) { if (qp.REORDER_VIEWS && recentlyUsedViews.Count > 0) { // move recently used views toward the end List reorderedViews = new List (); foreach (T_Tile view in views) { if (false == recentlyUsedViews.Contains(view)) { reorderedViews.Add(view); } } reorderedViews.AddRange(recentlyUsedViews); views = reorderedViews; } RewritingPass rewritingPass = new RewritingPass (toFill, toAvoid, views, qp); return rewritingPass.RewriteQuery(out rewriting); } private bool RewriteQuery(out T_Tile rewriting) { rewriting = m_toFill; T_Tile rewritingSoFar; if (false == FindRewritingByIncludedAndDisjoint(out rewritingSoFar)) { if (false == FindContributingView(out rewritingSoFar)) { return false; } } bool hasExtraTuples = !m_qp.IsDisjointFrom(rewritingSoFar, m_toAvoid); // try to cut off extra tuples using joins if (hasExtraTuples) { foreach (T_Tile view in AvailableViews) { if (TryJoin(view, ref rewritingSoFar)) { hasExtraTuples = false; break; } } } // try to cut off extra tuples using anti-semijoins if (hasExtraTuples) { foreach (T_Tile view in AvailableViews) { if (TryAntiSemiJoin(view, ref rewritingSoFar)) { hasExtraTuples = false; break; } } } if (hasExtraTuples) { return false; // won't be able to cut off extra tuples } // remove redundant joins and anti-semijoins RewritingSimplifier .TrySimplifyJoinRewriting(ref rewritingSoFar, m_toAvoid, m_usedViews, m_qp); // find rewriting for missing tuples, if any T_Tile missingTuples = m_qp.AntiSemiJoin(m_toFill, rewritingSoFar); if (!m_qp.IsEmpty(missingTuples)) { T_Tile rewritingForMissingTuples; if (false == RewritingPass .RewriteQueryInternal(missingTuples, m_toAvoid, out rewritingForMissingTuples, m_views, new HashSet (m_usedViews.Keys), m_qp)) { rewriting = rewritingForMissingTuples; return false; // failure } else { // Although a more general optimization for UNIONs will handle this case, // adding this check reduces the overall number of containment tests if (m_qp.IsContainedIn(rewritingSoFar, rewritingForMissingTuples)) { rewritingSoFar = rewritingForMissingTuples; } else { rewritingSoFar = m_qp.Union(rewritingSoFar, rewritingForMissingTuples); } } } // if we reached this point, we have a successful rewriting rewriting = rewritingSoFar; return true; } // returns true if no more extra tuples are left private bool TryJoin(T_Tile view, ref T_Tile rewriting) { T_Tile newRewriting = m_qp.Join(rewriting, view); if (!m_qp.IsEmpty(newRewriting)) { m_usedViews[view] = TileOpKind.Join; rewriting = newRewriting; return m_qp.IsDisjointFrom(rewriting, m_toAvoid); } return false; } // returns true if no more extra tuples are left private bool TryAntiSemiJoin(T_Tile view, ref T_Tile rewriting) { T_Tile newRewriting = m_qp.AntiSemiJoin(rewriting, view); if (!m_qp.IsEmpty(newRewriting)) { m_usedViews[view] = TileOpKind.AntiSemiJoin; rewriting = newRewriting; return m_qp.IsDisjointFrom(rewriting, m_toAvoid); } return false; } // Try to find a rewriting by intersecting all views which contain the query // and subtracting all views that are disjoint from the query private bool FindRewritingByIncludedAndDisjoint(out T_Tile rewritingSoFar) { // intersect all views in which m_toFill is contained rewritingSoFar = null; foreach (T_Tile view in AvailableViews) { if (m_qp.IsContainedIn(m_toFill, view)) // query <= view { if (rewritingSoFar == null) { rewritingSoFar = view; m_usedViews[view] = TileOpKind.Join; } else { T_Tile newRewriting = m_qp.Join(rewritingSoFar, view); if (!m_qp.IsContainedIn(rewritingSoFar, newRewriting)) { rewritingSoFar = newRewriting; m_usedViews[view] = TileOpKind.Join; // it is a useful join } else { continue; // useless join } } if (m_qp.IsContainedIn(rewritingSoFar, m_toFill)) { return true; } } } // subtract all views that are disjoint from m_toFill if (rewritingSoFar != null) { foreach (T_Tile view in AvailableViews) { if (m_qp.IsDisjointFrom(m_toFill, view)) // query ^ view = {} { if (!m_qp.IsDisjointFrom(rewritingSoFar, view)) { rewritingSoFar = m_qp.AntiSemiJoin(rewritingSoFar, view); m_usedViews[view] = TileOpKind.AntiSemiJoin; if (m_qp.IsContainedIn(rewritingSoFar, m_toFill)) { return true; } } } } } return rewritingSoFar != null; } private bool FindContributingView(out T_Tile rewriting) { // find some view that helps reduce toFill foreach (T_Tile view in AvailableViews) { if (false == m_qp.IsDisjointFrom(view, m_toFill)) { rewriting = view; m_usedViews[view] = TileOpKind.Join; // positive, intersected return true; } } rewriting = null; return false; } private IEnumerable AvailableViews { get { return m_views.Where(view => !m_usedViews.ContainsKey(view)); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- DataGrid.cs
- DataRecord.cs
- JsonDeserializer.cs
- RankException.cs
- WindowsEditBoxRange.cs
- StateRuntime.cs
- Send.cs
- SizeConverter.cs
- HtmlTitle.cs
- ListViewAutomationPeer.cs
- WindowsTab.cs
- XmlValidatingReaderImpl.cs
- BinaryMessageFormatter.cs
- ProfileModule.cs
- XmlBufferedByteStreamReader.cs
- NavigationHelper.cs
- OleDbErrorCollection.cs
- OleDbPropertySetGuid.cs
- CertificateManager.cs
- EntryWrittenEventArgs.cs
- HandleExceptionArgs.cs
- PointIndependentAnimationStorage.cs
- DataColumnMapping.cs
- MouseDevice.cs
- ApplicationActivator.cs
- SHA512Managed.cs
- EncryptedXml.cs
- BasicViewGenerator.cs
- RegexGroupCollection.cs
- InvokeGenerator.cs
- CodeBlockBuilder.cs
- StructuralType.cs
- RequestStatusBarUpdateEventArgs.cs
- LoadedOrUnloadedOperation.cs
- _ScatterGatherBuffers.cs
- WebPartConnectionsConnectVerb.cs
- RectAnimationUsingKeyFrames.cs
- User.cs
- CalendarAutomationPeer.cs
- PropertyValueUIItem.cs
- IPHostEntry.cs
- InputLanguageSource.cs
- DataObjectSettingDataEventArgs.cs
- ListItemParagraph.cs
- SerializationSectionGroup.cs
- DelegateSerializationHolder.cs
- AttachedAnnotationChangedEventArgs.cs
- StagingAreaInputItem.cs
- ProfessionalColorTable.cs
- DbFunctionCommandTree.cs
- JsonReader.cs
- HtmlProps.cs
- ParsedAttributeCollection.cs
- GenericIdentity.cs
- SqlDataAdapter.cs
- Matrix3DValueSerializer.cs
- TransformPatternIdentifiers.cs
- ApplicationActivator.cs
- InitializerFacet.cs
- EnumType.cs
- DbException.cs
- InternalConfigEventArgs.cs
- AttributeExtensions.cs
- ParserStack.cs
- XPathBinder.cs
- AppSettingsSection.cs
- DataSysAttribute.cs
- QueryPageSettingsEventArgs.cs
- PhonemeEventArgs.cs
- ArithmeticException.cs
- ScopedKnownTypes.cs
- PointF.cs
- DesignerCategoryAttribute.cs
- XmlReader.cs
- EntityContainerRelationshipSet.cs
- PhonemeEventArgs.cs
- XmlDataSourceNodeDescriptor.cs
- IdentityModelStringsVersion1.cs
- TextTreeDeleteContentUndoUnit.cs
- TextTreeRootNode.cs
- SecurityCredentialsManager.cs
- SystemIPAddressInformation.cs
- SystemResourceHost.cs
- IItemContainerGenerator.cs
- XPathDocumentBuilder.cs
- StrongNameKeyPair.cs
- RuntimeResourceSet.cs
- SelectionBorderGlyph.cs
- LambdaCompiler.Logical.cs
- SimpleWebHandlerParser.cs
- GlyphRunDrawing.cs
- StylusPointProperty.cs
- ConfigsHelper.cs
- LogicalTreeHelper.cs
- GlyphingCache.cs
- CallbackValidatorAttribute.cs
- ActivityExecutor.cs
- TemplatePropertyEntry.cs
- HttpClientCertificate.cs
- FocusWithinProperty.cs