Class DistinctNode
- java.lang.Object
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- org.apache.derby.impl.sql.compile.QueryTreeNode
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- org.apache.derby.impl.sql.compile.ResultSetNode
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- org.apache.derby.impl.sql.compile.FromTable
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- org.apache.derby.impl.sql.compile.SingleChildResultSetNode
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- org.apache.derby.impl.sql.compile.DistinctNode
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- All Implemented Interfaces:
Optimizable
,Visitable
class DistinctNode extends SingleChildResultSetNode
A DistinctNode represents a result set for a distinct operation on a select. It has the same description as its input result set. For the most part, it simply delegates operations to its childResultSet, which is currently expected to be a ProjectRestrictResultSet generated for a SelectNode. NOTE: A DistinctNode extends FromTable since it can exist in a FromList.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
ResultSetNode.QueryExpressionClauses
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Field Summary
Fields Modifier and Type Field Description (package private) boolean
inSortedOrder
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Fields inherited from class org.apache.derby.impl.sql.compile.SingleChildResultSetNode
childResult, hasTrulyTheBestAccessPath
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Fields inherited from class org.apache.derby.impl.sql.compile.FromTable
ADD_PLAN, bestAccessPath, bestCostEstimate, bestSortAvoidancePath, correlationName, corrTableName, currentAccessPath, hashKeyColumns, initialCapacity, level, LOAD_PLAN, loadFactor, maxCapacity, origTableName, REMOVE_PLAN, tableNumber, tableProperties, trulyTheBestAccessPath, userSpecifiedJoinStrategy
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Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX
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Constructor Summary
Constructors Constructor Description DistinctNode(ResultSetNode childResult, boolean inSortedOrder, java.util.Properties tableProperties, ContextManager cm)
Constructor for a DistinctNode.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description CostEstimate
estimateCost(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering)
Estimate the cost of scanning this Optimizable using the given predicate list with the given conglomerate.(package private) void
generate(ActivationClassBuilder acb, MethodBuilder mb)
generate the distinct result set operating over the source result set.(package private) boolean
isOrderedOn(ColumnReference[] crs, boolean permuteOrdering, java.util.List<FromBaseTable> fbtHolder)
Return whether or not the underlying ResultSet tree is ordered on the specified columns.(package private) ResultSetNode
optimize(DataDictionary dataDictionary, PredicateList predicates, double outerRows)
Optimize this DistinctNode.CostEstimate
optimizeIt(Optimizer optimizer, OptimizablePredicateList predList, CostEstimate outerCost, RowOrdering rowOrdering)
Choose the best access path for this Optimizable.boolean
pushOptPredicate(OptimizablePredicate optimizablePredicate)
Push an OptimizablePredicate down, if this node accepts it.-
Methods inherited from class org.apache.derby.impl.sql.compile.SingleChildResultSetNode
acceptChildren, addNewPredicate, adjustForSortElimination, adjustForSortElimination, changeAccessPath, decrementLevel, ensurePredicateList, flattenableInFromSubquery, forUpdate, getChildResult, getFinalCostEstimate, getFromTableByName, getTrulyTheBestAccessPath, initAccessPaths, isNotExists, isOneRowResultSet, modifyAccessPaths, preprocess, printSubNodes, pullOptPredicates, pushExpressions, referencesSessionSchema, referencesTarget, reflectionNeededForProjection, setChildResult, setLevel, subqueryReferencesTarget, updateBestPlanMap, updateTargetLockMode
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Methods inherited from class org.apache.derby.impl.sql.compile.FromTable
assignCostEstimate, canBeOrdered, columnsAreUpdatable, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, feasibleJoinStrategy, fillInReferencedTableMap, flatten, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCorrelationName, getCostEstimate, getCurrentAccessPath, getExposedName, getLevel, getMergeTableID, getName, getNumColumnsReturned, getOrigTableName, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getUserSpecifiedJoinStrategy, hashKeyColumns, hasLargeObjectColumns, hasTableNumber, initialCapacity, isBaseTable, isCoveringIndex, isFlattenableJoinNode, isJoinColumnForRightOuterJoin, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, LOJ_reorderable, markUpdatableByCursor, maxCapacity, memoryUsageOK, modifyAccessPath, needsSpecialRCLBinding, nextAccessPath, optimizeSubqueries, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setCostEstimateCost, setHashKeyColumns, setMergeTableID, setOrigTableName, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, toString, transformOuterJoins, uniqueJoin, verifyProperties
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Methods inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
assignResultSetNumber, bindExpressions, bindExpressionsWithTables, bindNonVTITables, bindResultColumns, bindResultColumns, bindTargetExpressions, bindUntypedNullsToResultColumns, bindVTITables, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, generateNormalizationResultSet, generateResultSet, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCandidateFinalCostEstimate, getCostEstimate, getCursorTargetTable, getFromList, getMatchingColumn, getNewCostEstimate, getOptimizer, getOptimizerImpl, getRCLForInsert, getReferencedTableMap, getResultColumns, getResultSetNumber, getScratchCostEstimate, isCursorTargetTable, isInsertSource, isPossibleDistinctScan, isStatementResultSet, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, modifyAccessPaths, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, parseDefault, performMaterialization, printQueryExpressionSuffixClauses, projectResultColumns, pushOffsetFetchFirst, pushOrderByList, pushQueryExpressionSuffix, rejectParameters, rejectXMLValues, renameGeneratedResultNames, replaceOrForbidDefaults, returnsAtMostOneRow, setCandidateFinalCostEstimate, setCostEstimate, setCursorTargetTable, setInsertSource, setOptimizer, setReferencedTableMap, setResultColumns, setResultSetNumber, setResultToBooleanTrueNode, setScratchCostEstimate, setTableConstructorTypes, verifySelectStarSubquery
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Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, addTag, addUDTUsagePriv, addUDTUsagePriv, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, copyTagsFrom, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContext, getContextManager, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getLongProperty, getNullNode, getOffsetOrderedNodes, getOptimizerFactory, getOptimizerTracer, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, getUDTDesc, isAtomic, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, optimizerTracingIsOn, orReliability, parseSearchCondition, parseStatement, printLabel, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.derby.iapi.sql.compile.Optimizable
getDataDictionary, getOptimizerTracer, getReferencedTableMap, getResultSetNumber, optimizerTracingIsOn
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Methods inherited from interface org.apache.derby.iapi.sql.compile.Visitable
accept, addTag, taggedWith
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Constructor Detail
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DistinctNode
DistinctNode(ResultSetNode childResult, boolean inSortedOrder, java.util.Properties tableProperties, ContextManager cm) throws StandardException
Constructor for a DistinctNode.- Parameters:
childResult
- The child ResultSetNodeinSortedOrder
- Whether or not the child ResultSetNode returns its output in sorted order.tableProperties
- Properties list associated with the tablecm
- The context manager- Throws:
StandardException
- Thrown on error
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Method Detail
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optimizeIt
public CostEstimate optimizeIt(Optimizer optimizer, OptimizablePredicateList predList, CostEstimate outerCost, RowOrdering rowOrdering) throws StandardException
Description copied from interface:Optimizable
Choose the best access path for this Optimizable.- Specified by:
optimizeIt
in interfaceOptimizable
- Overrides:
optimizeIt
in classFromTable
- Parameters:
optimizer
- Optimizer to use.predList
- The predicate list to optimize againstouterCost
- The CostEstimate for the outer tables in the join order, telling how many times this Optimizable will be scanned.rowOrdering
- The row ordering for all the tables in the join order, including this one.- Returns:
- The optimizer's estimated cost of the best access path.
- Throws:
StandardException
- Thrown on error- See Also:
Optimizable.optimizeIt(org.apache.derby.iapi.sql.compile.Optimizer, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.CostEstimate, org.apache.derby.iapi.sql.compile.RowOrdering)
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estimateCost
public CostEstimate estimateCost(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering) throws StandardException
Description copied from interface:Optimizable
Estimate the cost of scanning this Optimizable using the given predicate list with the given conglomerate. It is assumed that the predicate list has already been classified. This cost estimate is just for one scan, not for the life of the query.- Specified by:
estimateCost
in interfaceOptimizable
- Overrides:
estimateCost
in classFromTable
- Parameters:
predList
- The predicate list to optimize againstcd
- The conglomerate descriptor to get the cost ofouterCost
- The estimated cost of the part of the plan outer to this optimizable.optimizer
- The optimizer to use to help estimate the costrowOrdering
- The row ordering for all the tables in the join order, including this one.- Returns:
- The estimated cost of doing the scan
- Throws:
StandardException
- Thrown on error- See Also:
Optimizable.estimateCost(org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.dictionary.ConglomerateDescriptor, org.apache.derby.iapi.sql.compile.CostEstimate, org.apache.derby.iapi.sql.compile.Optimizer, org.apache.derby.iapi.sql.compile.RowOrdering)
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pushOptPredicate
public boolean pushOptPredicate(OptimizablePredicate optimizablePredicate) throws StandardException
Description copied from interface:Optimizable
Push an OptimizablePredicate down, if this node accepts it.- Specified by:
pushOptPredicate
in interfaceOptimizable
- Overrides:
pushOptPredicate
in classFromTable
- Parameters:
optimizablePredicate
- OptimizablePredicate to push down.- Returns:
- Whether or not the predicate was pushed down.
- Throws:
StandardException
- Thrown on error- See Also:
Optimizable.pushOptPredicate(org.apache.derby.iapi.sql.compile.OptimizablePredicate)
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optimize
ResultSetNode optimize(DataDictionary dataDictionary, PredicateList predicates, double outerRows) throws StandardException
Optimize this DistinctNode.- Overrides:
optimize
in classSingleChildResultSetNode
- Parameters:
dataDictionary
- The DataDictionary to use for optimizationpredicates
- The PredicateList to optimize. This should be a join predicate.outerRows
- The number of outer joining rows- Returns:
- ResultSetNode The top of the optimized subtree
- Throws:
StandardException
- Thrown on error
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isOrderedOn
boolean isOrderedOn(ColumnReference[] crs, boolean permuteOrdering, java.util.List<FromBaseTable> fbtHolder)
Return whether or not the underlying ResultSet tree is ordered on the specified columns. RESOLVE - This method currently only considers the outermost table of the query block.- Overrides:
isOrderedOn
in classSingleChildResultSetNode
- Parameters:
crs
- The specified ColumnReference[]permuteOrdering
- Whether or not the order of the CRs in the array can be permutedfbtHolder
- List that is to be filled with the FromBaseTable- Returns:
- Whether the underlying ResultSet tree is ordered on the specified column.
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generate
void generate(ActivationClassBuilder acb, MethodBuilder mb) throws StandardException
generate the distinct result set operating over the source result set.- Overrides:
generate
in classQueryTreeNode
- Parameters:
acb
- The ActivationClassBuilder for the class being builtmb
- The method for the generated code to go into- Throws:
StandardException
- Thrown on error
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