Class FromTable

java.lang.Object

org.apache.derby.impl.sql.compile.QueryTreeNode

org.apache.derby.impl.sql.compile.ResultSetNode

org.apache.derby.impl.sql.compile.FromTable

All Implemented Interfaces:

Optimizable, Visitable

Direct Known Subclasses:

CurrentOfNode, FromBaseTable, FromSubquery, FromVTI, IndexToBaseRowNode, RowResultSetNode, SingleChildResultSetNode, TableOperatorNode

abstract class FromTable
extends ResultSetNode
implements Optimizable

A FromTable represents a table in the FROM clause of a DML statement. It can be either a base table, a subquery or a project restrict.

See Also:

• FromBaseTable
• FromSubquery
• ProjectRestrictNode

Nested Class Summary

Nested classes/interfaces inherited from class ResultSetNode

ResultSetNode.QueryExpressionClauses

Field Summary

Fields

Modifier and Type	Field	Description
private int	_mergeTableID	for resolving column references in MERGE statements in tough cases
protected static final short	ADD_PLAN
(package private) AccessPathImpl	bestAccessPath
protected CostEstimate	bestCostEstimate
private HashMap<Object, AccessPathImpl>	bestPlanMap	Set of object->trulyTheBestAccessPath mappings used to keep track of which of this Optimizable's "trulyTheBestAccessPath" was the best with respect to a specific outer query or ancestor node.
(package private) AccessPathImpl	bestSortAvoidancePath
private boolean	considerSortAvoidancePath
(package private) String	correlationName
(package private) TableName	corrTableName
(package private) AccessPathImpl	currentAccessPath
(package private) int[]	hashKeyColumns
(package private) int	initialCapacity
private int	joinStrategyNumber
(package private) int	level
protected static final short	LOAD_PLAN
(package private) float	loadFactor
(package private) int	maxCapacity
protected TableName	origTableName	the original unbound table name
private double	perRowUsage
protected static final short	REMOVE_PLAN	Operations that can be performed on bestPlanMap.
(package private) int	tableNumber
(package private) Properties	tableProperties
(package private) AccessPathImpl	trulyTheBestAccessPath
protected String	userSpecifiedJoinStrategy

Fields inherited from class QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor	Description
FromTable(String correlationName, Properties tableProperties, ContextManager cm)	Constructor for a table in a FROM list.

Method Summary

Modifier and Type	Method	Description
(package private) void	acceptChildren(Visitor v)	Accept the visitor for all visitable children of this node.
protected void	assignCostEstimate(CostEstimate newCostEstimate)	Assign the cost estimate in this node to the given cost estimate.
protected boolean	canBeOrdered()	Most Optimizables cannot be ordered
(package private) boolean	columnsAreUpdatable()	Return true if some columns in this table are updatable.
boolean	considerSortAvoidancePath()	Check whether this optimizable's sort avoidance path should be considered.
int	convertAbsoluteToRelativeColumnPosition(int absolutePosition)	Convert an absolute to a relative 0-based column position.
protected boolean	cursorTargetTable()	Is this a table that has a FOR UPDATE clause.
(package private) void	decrementLevel(int decrement)	Decrement (query block) level (0-based) for this FromTable.
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.
boolean	feasibleJoinStrategy(OptimizablePredicateList predList, Optimizer optimizer)	Is the current proposed join strategy for this optimizable feasible given the predicate list?
(package private) void	fillInReferencedTableMap(JBitSet passedMap)	Fill the referencedTableMap with this ResultSetNode.
(package private) FromList	flatten(ResultColumnList rcl, PredicateList outerPList, SubqueryList sql, GroupByList gbl, ValueNode havingClause)	Flatten this FromTable into the outer query block.
boolean	forUpdate()	Return true if this is the target table of an update
String	getBaseTableName()	Get the table name of this Optimizable.
AccessPath	getBestAccessPath()	Get the best access path for this Optimizable.
AccessPath	getBestSortAvoidancePath()	Get the best sort-avoidance path for this Optimizable.
String	getCorrelationName()	Get this table's correlation name, if any.
protected CostEstimate	getCostEstimate(Optimizer optimizer)
AccessPath	getCurrentAccessPath()	Get the current access path under consideration for this Optimizable
(package private) String	getExposedName()	Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.
(package private) CostEstimate	getFinalCostEstimate()	Get the final CostEstimate for this FromTable.
(package private) FromTable	getFromTableByName(String name, String schemaName, boolean exactMatch)	Determine whether or not the specified name is an exposed name in the current query block.
(package private) int	getLevel()	Get the (query block) level (0-based) for this FromTable.
(package private) int	getMergeTableID()	get the merge table id
String	getName()	Get the (exposed) name of this Optimizable
int	getNumColumnsReturned()	Get the number of the number of columns returned by this Optimizable.
(package private) TableName	getOrigTableName()	Gets the original or unbound table name for this FromTable.
private double	getPerRowUsage()
Properties	getProperties()	Get the Properties list, if any, associated with this optimizable.
(package private) ResultColumnList	getResultColumnsForList(TableName allTableName, ResultColumnList inputRcl, TableName tableName)	Return a ResultColumnList with all of the columns in this table.
(package private) SchemaDescriptor	getSchemaDescriptor()	Get a schema descriptor for the given table.
(package private) SchemaDescriptor	getSchemaDescriptor(TableName tableName)	Get a schema descriptor for the given table.
protected CostEstimate	getScratchCostEstimate(Optimizer optimizer)
TableDescriptor	getTableDescriptor()	Get the table descriptor for this table (if any).
(package private) TableName	getTableName()	Return a TableName node representing this FromTable.
int	getTableNumber()	Get this Optimizable's table number
AccessPath	getTrulyTheBestAccessPath()	Get the best access path overall for this Optimizable.
(package private) String	getUserSpecifiedJoinStrategy()	Return the user specified join strategy, if any for this table.
int[]	hashKeyColumns()	Return the hash key column numbers, for hash join strategy
boolean	hasLargeObjectColumns()	Check if any columns containing large objects (BLOBs or CLOBs) are referenced in this table.
boolean	hasTableNumber()	Return true if this Optimizable has a table number
void	initAccessPaths(Optimizer optimizer)	Init the access paths for this optimizable.
int	initialCapacity()	Return the initial capacity of the hash table, for hash join strategy
boolean	isBaseTable()	Tell whether this Optimizable represents a base table
boolean	isCoveringIndex(ConglomerateDescriptor cd)	Return whether or not this is a covering index.
(package private) boolean	isFlattenableJoinNode()	Is this FromTable a JoinNode which can be flattened into the parents FromList.
(package private) void	isJoinColumnForRightOuterJoin(ResultColumn rc)	No-op in FromTable.
boolean	isMaterializable()	Tell whether this Optimizable is materializable
boolean	isOneRowScan()	Will the optimizable return at most 1 row per scan?
boolean	isTargetTable()	Is the optimizable the target table of an update or delete?
boolean	legalJoinOrder(JBitSet assignedTableMap)	Can this Optimizable appear at the current location in the join order.
float	loadFactor()	Return the load factor of the hash table, for hash join strategy
(package private) boolean	LOJ_reorderable(int numTables)	no LOJ reordering for this FromTable.
protected void	markUpdatableByCursor(List<String> updateColumns)	Mark as updatable all the columns in the result column list of this FromBaseTable that match the columns in the given update column list.
int	maxCapacity(JoinStrategy joinStrategy, int maxMemoryPerTable)	Return the maximum capacity of the hash table, for hash join strategy
boolean	memoryUsageOK(double rowCount, int maxMemoryPerTable)
Optimizable	modifyAccessPath(JBitSet outerTables)	Modify the access path for this Optimizable, as necessary.
(package private) boolean	needsSpecialRCLBinding()
boolean	nextAccessPath(Optimizer optimizer, OptimizablePredicateList predList, RowOrdering rowOrdering)	Choose the next access path to evaluate for this Optimizable.
CostEstimate	optimizeIt(Optimizer optimizer, OptimizablePredicateList predList, CostEstimate outerCost, RowOrdering rowOrdering)	Choose the best access path for this Optimizable.
(package private) void	optimizeSubqueries(DataDictionary dd, double rowCount)	Optimize any subqueries that haven't been optimized any where else.
void	pullOptPredicates(OptimizablePredicateList optimizablePredicates)	Pull all the OptimizablePredicates from this Optimizable and put them in the given OptimizablePredicateList.
(package private) void	pushExpressions(PredicateList predicateList)	Push expressions down to the first ResultSetNode which can do expression evaluation and has the same referenced table map.
boolean	pushOptPredicate(OptimizablePredicate optimizablePredicate)	Push an OptimizablePredicate down, if this node accepts it.
void	rememberAsBest(int planType, Optimizer optimizer)	Remember the current access path as the best one (so far).
void	rememberJoinStrategyAsBest(AccessPath ap)	Remember the current join strategy as the best one so far in this join order.
void	rememberSortAvoidancePath()	Mark this optimizable so that its sort avoidance path will be considered.
protected void	resetJoinStrategies(Optimizer optimizer)	This method is called when this table is placed in a potential join order, or when a new conglomerate is being considered.
protected void	setCostEstimateCost(CostEstimate newCostEstimate)	Set the cost estimate in this node to the given cost estimate.
void	setHashKeyColumns(int[] columnNumbers)	Set the hash key column numbers, for hash join strategy
(package private) void	setLevel(int level)	Set the (query block) level (0-based) for this FromTable.
(package private) void	setMergeTableID(int mergeTableID)	set the merge table id
(package private) void	setOrigTableName(TableName tableName)	Sets the original or unbound table name for this FromTable.
void	setProperties(Properties tableProperties)	Set the Properties list for this optimizalbe.
(package private) void	setTableNumber(int tableNumber)	Set the table # for this table.
void	startOptimizing(Optimizer optimizer, RowOrdering rowOrdering)	Begin the optimization process for this Optimizable.
boolean	supportsMultipleInstantiations()	Tell whether this Optimizable can be instantiated multiple times
protected void	tellRowOrderingAboutConstantColumns(RowOrdering rowOrdering, OptimizablePredicateList predList)	Tell the given RowOrdering about any columns that are constant due to their being equality comparisons with constant expressions.
String	toString()	Convert this object to a String.
(package private) FromTable	transformOuterJoins(ValueNode predicateTree, int numTables)	Transform any Outer Join into an Inner Join where applicable.
double	uniqueJoin(OptimizablePredicateList predList)	Does this optimizable have a uniqueness condition on the given predicate list, and if so, how many unique keys will be returned per scan.
void	updateBestPlanMap(short action, Object planKey)	When remembering "truly the best" access path for an Optimizable, we have to keep track of which OptimizerImpl the "truly the best" access is for.
void	verifyProperties(DataDictionary dDictionary)	Verify that the Properties list with optimizer overrides, if specified, is valid

Methods inherited from class ResultSetNode

addNewPredicate, adjustForSortElimination, adjustForSortElimination, assignResultSetNumber, bindExpressions, bindExpressionsWithTables, bindNonVTITables, bindResultColumns, bindResultColumns, bindTargetExpressions, bindUntypedNullsToResultColumns, bindVTITables, changeAccessPath, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, ensurePredicateList, flattenableInFromSubquery, generateNormalizationResultSet, generateResultSet, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCandidateFinalCostEstimate, getCostEstimate, getCursorTargetTable, getFromList, getMatchingColumn, getNewCostEstimate, getOptimizer, getOptimizerImpl, getRCLForInsert, getReferencedTableMap, getResultColumns, getResultSetNumber, getScratchCostEstimate, isCursorTargetTable, isInsertSource, isNotExists, isOneRowResultSet, isOrderedOn, isPossibleDistinctScan, isStatementResultSet, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, modifyAccessPaths, modifyAccessPaths, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, optimize, parseDefault, performMaterialization, preprocess, printQueryExpressionSuffixClauses, printSubNodes, projectResultColumns, pushOffsetFetchFirst, pushOrderByList, pushQueryExpressionSuffix, referencesTarget, rejectParameters, rejectXMLValues, renameGeneratedResultNames, replaceOrForbidDefaults, returnsAtMostOneRow, setCandidateFinalCostEstimate, setCostEstimate, setCursorTargetTable, setInsertSource, setOptimizer, setReferencedTableMap, setResultColumns, setResultSetNumber, setResultToBooleanTrueNode, setScratchCostEstimate, setTableConstructorTypes, subqueryReferencesTarget, updateTargetLockMode, verifySelectStarSubquery

Methods inherited from class QueryTreeNode

accept, addTag, addUDTUsagePriv, addUDTUsagePriv, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, copyTagsFrom, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, generate, 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, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist

Methods inherited from class Object

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

Methods inherited from interface Optimizable

getDataDictionary, getOptimizerTracer, getReferencedTableMap, getResultSetNumber, optimizerTracingIsOn

Methods inherited from interface Visitable

accept, addTag, taggedWith

Field Details

tableProperties

Properties tableProperties

correlationName

String correlationName

corrTableName

TableName corrTableName

tableNumber

int tableNumber

level

int level

hashKeyColumns

int[] hashKeyColumns

initialCapacity

int initialCapacity

loadFactor

float loadFactor

maxCapacity

int maxCapacity

currentAccessPath

AccessPathImpl currentAccessPath

bestAccessPath

AccessPathImpl bestAccessPath

bestSortAvoidancePath

AccessPathImpl bestSortAvoidancePath

trulyTheBestAccessPath

AccessPathImpl trulyTheBestAccessPath

joinStrategyNumber

private int joinStrategyNumber

userSpecifiedJoinStrategy

protected String userSpecifiedJoinStrategy

bestCostEstimate

protected CostEstimate bestCostEstimate

perRowUsage

private double perRowUsage

considerSortAvoidancePath

private boolean considerSortAvoidancePath

bestPlanMap

private HashMap<Object, AccessPathImpl> bestPlanMap

Set of object->trulyTheBestAccessPath mappings used to keep track of which of this Optimizable's "trulyTheBestAccessPath" was the best with respect to a specific outer query or ancestor node. In the case of an outer query, the object key will be an instance of OptimizerImpl. In the case of an ancestor node, the object key will be that node itself. Each ancestor node or outer query could potentially have a different idea of what this Optimizable's "best access path" is, so we have to keep track of them all.

REMOVE_PLAN

protected static final short REMOVE_PLAN

Operations that can be performed on bestPlanMap.

See Also:

• Constant Field Values

ADD_PLAN

protected static final short ADD_PLAN

See Also:

• Constant Field Values

LOAD_PLAN

protected static final short LOAD_PLAN

See Also:

• Constant Field Values

origTableName

protected TableName origTableName

the original unbound table name

_mergeTableID

private int _mergeTableID

for resolving column references in MERGE statements in tough cases

Constructor Details

FromTable

FromTable(String correlationName,
 Properties tableProperties,
 ContextManager cm)

Constructor for a table in a FROM list.

Parameters:

correlationName - The correlation name

tableProperties - Properties list associated with the table

cm - The context manager

Method Details

getCorrelationName

public String getCorrelationName()

Get this table's correlation name, if any.

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 interface Optimizable

Parameters:

optimizer - Optimizer to use.

predList - The predicate list to optimize against

outerCost - 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(Optimizer, OptimizablePredicateList, CostEstimate, RowOrdering)

nextAccessPath

public boolean nextAccessPath(Optimizer optimizer,
 OptimizablePredicateList predList,
 RowOrdering rowOrdering)
                       throws StandardException

Description copied from interface: Optimizable

Choose the next access path to evaluate for this Optimizable.

Specified by:

nextAccessPath in interface Optimizable

Parameters:

optimizer - Optimizer to use.

predList - The predicate list for this optimizable. The optimizer always passes null, and it is up to the optimizable object to pass along its own predicate list, if appropriate, when delegating this method.

rowOrdering - The row ordering for all the outer tables in the join order. This method will add the ordering of the next access path to the given RowOrdering.

Returns:

true means another access path was chosen, false means no more access paths to evaluate.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.nextAccessPath(Optimizer, OptimizablePredicateList, RowOrdering)

canBeOrdered

protected boolean canBeOrdered()

Most Optimizables cannot be ordered

getCurrentAccessPath

public AccessPath getCurrentAccessPath()

Description copied from interface: Optimizable

Get the current access path under consideration for this Optimizable

Specified by:

getCurrentAccessPath in interface Optimizable

See Also:

• Optimizable.getCurrentAccessPath()

getBestAccessPath

public AccessPath getBestAccessPath()

Description copied from interface: Optimizable

Get the best access path for this Optimizable.

Specified by:

getBestAccessPath in interface Optimizable

See Also:

• Optimizable.getBestAccessPath()

getBestSortAvoidancePath

public AccessPath getBestSortAvoidancePath()

Description copied from interface: Optimizable

Get the best sort-avoidance path for this Optimizable.

Specified by:

getBestSortAvoidancePath in interface Optimizable

See Also:

• Optimizable.getBestSortAvoidancePath()

getTrulyTheBestAccessPath

public AccessPath getTrulyTheBestAccessPath()

Description copied from interface: Optimizable

Get the best access path overall for this Optimizable.

Specified by:

getTrulyTheBestAccessPath in interface Optimizable

See Also:

• Optimizable.getTrulyTheBestAccessPath()

rememberSortAvoidancePath

public void rememberSortAvoidancePath()

Description copied from interface: Optimizable

Mark this optimizable so that its sort avoidance path will be considered.

Specified by:

rememberSortAvoidancePath in interface Optimizable

See Also:

• Optimizable.rememberSortAvoidancePath()

considerSortAvoidancePath

public boolean considerSortAvoidancePath()

Description copied from interface: Optimizable

Check whether this optimizable's sort avoidance path should be considered.

Specified by:

considerSortAvoidancePath in interface Optimizable

See Also:

• Optimizable.considerSortAvoidancePath()

rememberJoinStrategyAsBest

public void rememberJoinStrategyAsBest(AccessPath ap)

Description copied from interface: Optimizable

Remember the current join strategy as the best one so far in this join order.

Specified by:

rememberJoinStrategyAsBest in interface Optimizable

See Also:

• Optimizable.rememberJoinStrategyAsBest(AccessPath)

getTableDescriptor

public TableDescriptor getTableDescriptor()

Description copied from interface: Optimizable

Get the table descriptor for this table (if any). Only base tables have table descriptors - for the rest of the optimizables, this method returns null.

Specified by:

getTableDescriptor in interface Optimizable

See Also:

• Optimizable.getTableDescriptor()

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 interface Optimizable

Parameters:

optimizablePredicate - OptimizablePredicate to push down.

Returns:

Whether or not the predicate was pushed down.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.pushOptPredicate(OptimizablePredicate)

pullOptPredicates

public void pullOptPredicates(OptimizablePredicateList optimizablePredicates)
                       throws StandardException

Description copied from interface: Optimizable

Pull all the OptimizablePredicates from this Optimizable and put them in the given OptimizablePredicateList.

Specified by:

pullOptPredicates in interface Optimizable

Parameters:

optimizablePredicates - The list to put the pulled predicates in.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.pullOptPredicates(OptimizablePredicateList)

modifyAccessPath

public Optimizable modifyAccessPath(JBitSet outerTables)
                             throws StandardException

Description copied from interface: Optimizable

Modify the access path for this Optimizable, as necessary. This includes things like adding a result set to translate from index rows to base rows

Specified by:

modifyAccessPath in interface Optimizable

Parameters:

outerTables - Bit map of the tables that are outer to this one in the join order.

Returns:

The (potentially new) Optimizable at the top of the tree.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.modifyAccessPath(JBitSet)

isCoveringIndex

public boolean isCoveringIndex(ConglomerateDescriptor cd)
                        throws StandardException

Description copied from interface: Optimizable

Return whether or not this is a covering index. We expect to call this during generation, after access path selection is complete.

Specified by:

isCoveringIndex in interface Optimizable

Parameters:

cd - ConglomerateDesriptor for index to consider

Returns:

boolean Whether or not this is a covering index.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.isCoveringIndex(ConglomerateDescriptor)

getProperties

public Properties getProperties()

Description copied from interface: Optimizable

Get the Properties list, if any, associated with this optimizable.

Specified by:

getProperties in interface Optimizable

Returns:

The Properties list, if any, associated with this optimizable.

See Also:

• Optimizable.getProperties()

setProperties

public void setProperties(Properties tableProperties)

Description copied from interface: Optimizable

Set the Properties list for this optimizalbe.

Specified by:

setProperties in interface Optimizable

Parameters:

tableProperties - The Properties list for this optimizable.

See Also:

• Optimizable.setProperties(Properties)

verifyProperties

public void verifyProperties(DataDictionary dDictionary)
                      throws StandardException

Description copied from interface: Optimizable

Verify that the Properties list with optimizer overrides, if specified, is valid

Specified by:

verifyProperties in interface Optimizable

Parameters:

dDictionary - The DataDictionary to use.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.verifyProperties(DataDictionary)

getName

public String getName()
               throws StandardException

Description copied from interface: Optimizable

Get the (exposed) name of this Optimizable

Specified by:

getName in interface Optimizable

Returns:

The name of this Optimizable.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.getName()

getBaseTableName

public String getBaseTableName()

Description copied from interface: Optimizable

Get the table name of this Optimizable. Only base tables have table names (by the time we use this method, all views will have been resolved).

Specified by:

getBaseTableName in interface Optimizable

See Also:

• Optimizable.getBaseTableName()

convertAbsoluteToRelativeColumnPosition

public int convertAbsoluteToRelativeColumnPosition(int absolutePosition)

Description copied from interface: Optimizable

Convert an absolute to a relative 0-based column position. This is useful when generating qualifiers for partial rows from the store.

Specified by:

convertAbsoluteToRelativeColumnPosition in interface Optimizable

Parameters:

absolutePosition - The absolute 0-based column position for the column.

Returns:

The relative 0-based column position for the column.

See Also:

• Optimizable.convertAbsoluteToRelativeColumnPosition(int)

updateBestPlanMap

public void updateBestPlanMap(short action,
 Object planKey)
                       throws StandardException

Description copied from interface: Optimizable

When remembering "truly the best" access path for an Optimizable, we have to keep track of which OptimizerImpl the "truly the best" access is for. In most queries there will only be one OptimizerImpl in question, but in cases where there are nested subqueries, there will be one OptimizerImpl for every level of nesting, and each OptimizerImpl might have its own idea of what this Optimizable's "truly the best path" access path really is. In addition, there could be Optimizables above this Optimizable that might need to override the best path chosen during optimization. So whenever we save a "truly the best" path, we take note of which Optimizer/Optimizable told us to do so. Then as each level of subquery finishes optimization, the corresponding OptimizerImpl/Optimizable can load its preferred access path into this Optimizable's trulyTheBestAccessPath field and pass it up the tree, until eventually the outer-most OptimizerImpl can choose to either use the best path that it received from below (by calling "rememberAsBest()") or else use the path that it found to be "best" for itself. This method is what allows us to keep track of which OptimizerImpl or Optimizable saved which "best plan", and allows us to load the appropriate plans after each round of optimization.

Specified by:

updateBestPlanMap in interface Optimizable

Parameters:

action - Indicates whether we're adding, loading, or removing a best plan for the OptimizerImpl/Optimizable.

planKey - Object to use as the map key when adding/looking up a plan. If it is an instance of OptimizerImpl then it corresponds to an outer query; otherwise it's some Optimizable above this Optimizable that could potentially reject plans chosen by the OptimizerImpl to which this Optimizable belongs.

Throws:

StandardException

See Also:

• Optimizable.updateBestPlanMap(short, Object)

rememberAsBest

public void rememberAsBest(int planType,
 Optimizer optimizer)
                    throws StandardException

Description copied from interface: Optimizable

Remember the current access path as the best one (so far).

Specified by:

rememberAsBest in interface Optimizable

Parameters:

planType - The type of plan (one of Optimizer.NORMAL_PLAN or Optimizer.SORT_AVOIDANCE_PLAN)

optimizer - The OptimizerImpl that is telling this Optimizable to remember its current path as "truly the best".

Throws:

StandardException - thrown on error.

See Also:

• Optimizable.rememberAsBest(int, Optimizer)

startOptimizing

public void startOptimizing(Optimizer optimizer,
 RowOrdering rowOrdering)

Description copied from interface: Optimizable

Begin the optimization process for this Optimizable. This can be called many times for an Optimizable while optimizing a query - it will typically be called every time the Optimizable is placed in a potential join order.

Specified by:

startOptimizing in interface Optimizable

See Also:

• Optimizable.startOptimizing(Optimizer, RowOrdering)

resetJoinStrategies

protected void resetJoinStrategies(Optimizer optimizer)

This method is called when this table is placed in a potential join order, or when a new conglomerate is being considered. Set this join strategy number to 0 to indicate that no join strategy has been considered for this table yet.

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 interface Optimizable

Parameters:

predList - The predicate list to optimize against

cd - The conglomerate descriptor to get the cost of

outerCost - The estimated cost of the part of the plan outer to this optimizable.

optimizer - The optimizer to use to help estimate the cost

rowOrdering - 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(OptimizablePredicateList, ConglomerateDescriptor, CostEstimate, Optimizer, RowOrdering)

getFinalCostEstimate

CostEstimate getFinalCostEstimate()
                           throws StandardException

Get the final CostEstimate for this FromTable.

Overrides:

getFinalCostEstimate in class ResultSetNode

Returns:

The final CostEstimate for this FromTable, which is the costEstimate of trulyTheBestAccessPath if there is one. If there's no trulyTheBestAccessPath for this node, then we just return the value stored in costEstimate as a default.

Throws:

StandardException

isBaseTable

public boolean isBaseTable()

Description copied from interface: Optimizable

Tell whether this Optimizable represents a base table

Specified by:

isBaseTable in interface Optimizable

See Also:

• Optimizable.isBaseTable()

hasLargeObjectColumns

public boolean hasLargeObjectColumns()

Check if any columns containing large objects (BLOBs or CLOBs) are referenced in this table.

Specified by:

hasLargeObjectColumns in interface Optimizable

Returns:

true if at least one large object column is referenced, false otherwise

isMaterializable

public boolean isMaterializable()
                         throws StandardException

Description copied from interface: Optimizable

Tell whether this Optimizable is materializable

Specified by:

isMaterializable in interface Optimizable

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.isMaterializable()

supportsMultipleInstantiations

public boolean supportsMultipleInstantiations()

Description copied from interface: Optimizable

Tell whether this Optimizable can be instantiated multiple times

Specified by:

supportsMultipleInstantiations in interface Optimizable

See Also:

• Optimizable.supportsMultipleInstantiations()

getTableNumber

public int getTableNumber()

Description copied from interface: Optimizable

Get this Optimizable's table number

Specified by:

getTableNumber in interface Optimizable

See Also:

• Optimizable.getTableNumber()

hasTableNumber

public boolean hasTableNumber()

Description copied from interface: Optimizable

Return true if this Optimizable has a table number

Specified by:

hasTableNumber in interface Optimizable

See Also:

• Optimizable.hasTableNumber()

forUpdate

public boolean forUpdate()

Description copied from interface: Optimizable

Return true if this is the target table of an update

Specified by:

forUpdate in interface Optimizable

See Also:

• Optimizable.forUpdate()

initialCapacity

public int initialCapacity()

Description copied from interface: Optimizable

Return the initial capacity of the hash table, for hash join strategy

Specified by:

initialCapacity in interface Optimizable

See Also:

• Optimizable.initialCapacity()

loadFactor

public float loadFactor()

Description copied from interface: Optimizable

Return the load factor of the hash table, for hash join strategy

Specified by:

loadFactor in interface Optimizable

See Also:

• Optimizable.loadFactor()

maxCapacity

public int maxCapacity(JoinStrategy joinStrategy,
 int maxMemoryPerTable)
                throws StandardException

Description copied from interface: Optimizable

Return the maximum capacity of the hash table, for hash join strategy

Specified by:

maxCapacity in interface Optimizable

Parameters:

maxMemoryPerTable - The maximum number of bytes to be used. Ignored if the user has set a maximum number of rows for the Optimizable.

Throws:

StandardException - Standard error policy

See Also:

• Optimizable.maxCapacity(JoinStrategy, int)

getPerRowUsage

private double getPerRowUsage()
                       throws StandardException

Throws:

StandardException

hashKeyColumns

public int[] hashKeyColumns()

Description copied from interface: Optimizable

Return the hash key column numbers, for hash join strategy

Specified by:

hashKeyColumns in interface Optimizable

See Also:

• Optimizable.hashKeyColumns()

setHashKeyColumns

public void setHashKeyColumns(int[] columnNumbers)

Description copied from interface: Optimizable

Set the hash key column numbers, for hash join strategy

Specified by:

setHashKeyColumns in interface Optimizable

See Also:

• Optimizable.setHashKeyColumns(int[])

feasibleJoinStrategy

public boolean feasibleJoinStrategy(OptimizablePredicateList predList,
 Optimizer optimizer)
                             throws StandardException

Description copied from interface: Optimizable

Is the current proposed join strategy for this optimizable feasible given the predicate list?

Specified by:

feasibleJoinStrategy in interface Optimizable

Parameters:

predList - The predicate list that has been pushed down to this optimizable

optimizer - The optimizer to use.

Returns:

true means feasible

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.feasibleJoinStrategy(OptimizablePredicateList, Optimizer)

memoryUsageOK

public boolean memoryUsageOK(double rowCount,
 int maxMemoryPerTable)
                      throws StandardException

Specified by:

memoryUsageOK in interface Optimizable

Parameters:

rowCount -

maxMemoryPerTable -

Returns:

true if the memory usage of the proposed access path is OK, false if not.

Throws:

StandardException - standard error policy

See Also:

• Optimizable.memoryUsageOK(double, int)

isJoinColumnForRightOuterJoin

void isJoinColumnForRightOuterJoin(ResultColumn rc)

No-op in FromTable.

See Also:

• HalfOuterJoinNode.isJoinColumnForRightOuterJoin(ResultColumn)

legalJoinOrder

public boolean legalJoinOrder(JBitSet assignedTableMap)

Description copied from interface: Optimizable

Can this Optimizable appear at the current location in the join order. In other words, have the Optimizable's dependencies been satisfied?

Specified by:

legalJoinOrder in interface Optimizable

Parameters:

assignedTableMap - The tables that have been placed so far in the join order.

Returns:

Where or not this Optimizable can appear at the current location in the join order.

See Also:

• Optimizable.legalJoinOrder(JBitSet)

getNumColumnsReturned

public int getNumColumnsReturned()

Description copied from interface: Optimizable

Get the number of the number of columns returned by this Optimizable.

Specified by:

getNumColumnsReturned in interface Optimizable

Returns:

The number of the number of columns returned by this Optimizable.

See Also:

• Optimizable.getNumColumnsReturned()

isTargetTable

public boolean isTargetTable()

Description copied from interface: Optimizable

Is the optimizable the target table of an update or delete?

Specified by:

isTargetTable in interface Optimizable

Returns:

Whether or not the optimizable the target table of an update or delete.

See Also:

• Optimizable.isTargetTable()

isOneRowScan

public boolean isOneRowScan()
                     throws StandardException

Description copied from interface: Optimizable

Will the optimizable return at most 1 row per scan?

Specified by:

isOneRowScan in interface Optimizable

Returns:

Whether or not the optimizable will return at most 1 row per scan?

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.isOneRowScan()

initAccessPaths

public void initAccessPaths(Optimizer optimizer)

Description copied from interface: Optimizable

Init the access paths for this optimizable.

Specified by:

initAccessPaths in interface Optimizable

Parameters:

optimizer - The optimizer being used.

See Also:

• Optimizable.initAccessPaths(Optimizer)

uniqueJoin

public double uniqueJoin(OptimizablePredicateList predList)
                  throws StandardException

Description copied from interface: Optimizable

Does this optimizable have a uniqueness condition on the given predicate list, and if so, how many unique keys will be returned per scan.

Specified by:

uniqueJoin in interface Optimizable

Parameters:

predList - The predicate list to check

Returns:

<= 0 means there is no uniqueness condition > 0 means there is a uniqueness condition, and the return value is the number of rows per scan.

Throws:

StandardException - Thrown on error

See Also:

• Optimizable.uniqueJoin(OptimizablePredicateList)

getUserSpecifiedJoinStrategy

String getUserSpecifiedJoinStrategy()

Return the user specified join strategy, if any for this table.

Returns:

The user specified join strategy, if any for this table.

cursorTargetTable

protected boolean cursorTargetTable()

Is this a table that has a FOR UPDATE clause. Overridden by FromBaseTable.

Returns:

true/false

getCostEstimate

protected CostEstimate getCostEstimate(Optimizer optimizer)

getScratchCostEstimate

protected CostEstimate getScratchCostEstimate(Optimizer optimizer)

setCostEstimateCost

protected void setCostEstimateCost(CostEstimate newCostEstimate)

Set the cost estimate in this node to the given cost estimate.

assignCostEstimate

protected void assignCostEstimate(CostEstimate newCostEstimate)

Assign the cost estimate in this node to the given cost estimate.

toString

public String toString()

Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.

Overrides:

toString in class ResultSetNode

Returns:

This object as a String

getResultColumnsForList

ResultColumnList getResultColumnsForList(TableName allTableName,
 ResultColumnList inputRcl,
 TableName tableName)
                                  throws StandardException

Return a ResultColumnList with all of the columns in this table. (Used in expanding '*'s.) NOTE: Since this method is for expanding a "*" in the SELECT list, ResultColumn.expression will be a ColumnReference.

Parameters:

allTableName - The qualifier on the "*"

Returns:

ResultColumnList List of result columns from this table.

Throws:

StandardException - Thrown on error

pushExpressions

void pushExpressions(PredicateList predicateList)
              throws StandardException

Push expressions down to the first ResultSetNode which can do expression evaluation and has the same referenced table map. RESOLVE - This means only pushing down single table expressions to ProjectRestrictNodes today. Once we have a better understanding of how the optimizer will work, we can push down join clauses.

Parameters:

predicateList - The PredicateList.

Throws:

StandardException - Thrown on error

getExposedName

String getExposedName()
               throws StandardException

Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.

Returns:

The exposed name of this table.

Throws:

StandardException - Thrown on error

setTableNumber

void setTableNumber(int tableNumber)

Set the table # for this table.

Parameters:

tableNumber - The table # for this table.

getTableName

TableName getTableName()
                throws StandardException

Return a TableName node representing this FromTable. Expect this to be overridden (and used) by subclasses that may set correlationName to null.

Returns:

a TableName node representing this FromTable.

Throws:

StandardException - Thrown on error

setLevel

void setLevel(int level)

Set the (query block) level (0-based) for this FromTable.

Parameters:

level - The query block level for this FromTable.

getLevel

int getLevel()

Get the (query block) level (0-based) for this FromTable.

Returns:

int The query block level for this FromTable.

decrementLevel

void decrementLevel(int decrement)

Decrement (query block) level (0-based) for this FromTable. This is useful when flattening a subquery.

Specified by:

decrementLevel in class ResultSetNode

Parameters:

decrement - The amount to decrement by.

getSchemaDescriptor

SchemaDescriptor getSchemaDescriptor()
                              throws StandardException

Get a schema descriptor for the given table. Uses this.corrTableName.

Returns:

Schema Descriptor

Throws:

StandardException - throws on schema name that doesn't exist

getSchemaDescriptor

SchemaDescriptor getSchemaDescriptor(TableName tableName)
                              throws StandardException

Get a schema descriptor for the given table.

Parameters:

tableName - the table name

Returns:

Schema Descriptor

Throws:

StandardException - throws on schema name that doesn't exist

getFromTableByName

FromTable getFromTableByName(String name,
 String schemaName,
 boolean exactMatch)
                      throws StandardException

Determine whether or not the specified name is an exposed name in the current query block.

Overrides:

getFromTableByName in class ResultSetNode

Parameters:

name - The specified name to search for as an exposed name.

schemaName - Schema name, if non-null.

exactMatch - Whether or not we need an exact match on specified schema and table names or match on table id.

Returns:

The FromTable, if any, with the exposed name.

Throws:

StandardException - Thrown on error

isFlattenableJoinNode

boolean isFlattenableJoinNode()

Is this FromTable a JoinNode which can be flattened into the parents FromList.

Returns:

boolean Whether or not this FromTable can be flattened.

LOJ_reorderable

boolean LOJ_reorderable(int numTables)
                 throws StandardException

no LOJ reordering for this FromTable.

Throws:

StandardException

transformOuterJoins

FromTable transformOuterJoins(ValueNode predicateTree,
 int numTables)
                       throws StandardException

Transform any Outer Join into an Inner Join where applicable. (Based on the existence of a null intolerant predicate on the inner table.)

Parameters:

predicateTree - The predicate tree for the query block

Returns:

The new tree top (OuterJoin or InnerJoin).

Throws:

StandardException - Thrown on error

fillInReferencedTableMap

void fillInReferencedTableMap(JBitSet passedMap)

Fill the referencedTableMap with this ResultSetNode.

Overrides:

fillInReferencedTableMap in class ResultSetNode

Parameters:

passedMap - The table map to fill in.

markUpdatableByCursor

protected void markUpdatableByCursor(List<String> updateColumns)

Mark as updatable all the columns in the result column list of this FromBaseTable that match the columns in the given update column list. If the list is null, it means all the columns are updatable.

Parameters:

updateColumns - A list representing the columns that can be updated.

columnsAreUpdatable

boolean columnsAreUpdatable()

Return true if some columns in this table are updatable. This method is used in deciding whether updateRow() or insertRow() are allowable.

Returns:

true if some columns in this table are updatable.

flatten

FromList flatten(ResultColumnList rcl,
 PredicateList outerPList,
 SubqueryList sql,
 GroupByList gbl,
 ValueNode havingClause)
          throws StandardException

Flatten this FromTable into the outer query block. The steps in flattening are: o Mark all ResultColumns as redundant, so that they are "skipped over" at generate(). o Append the wherePredicates to the outer list. o Return the fromList so that the caller will merge the 2 lists

Parameters:

rcl - The RCL from the outer query

outerPList - PredicateList to append wherePredicates to.

sql - The SubqueryList from the outer query

gbl - The group by list, if any

havingClause - The HAVING clause, if any

Returns:

FromList The fromList from the underlying SelectNode.

Throws:

StandardException - Thrown on error

optimizeSubqueries

void optimizeSubqueries(DataDictionary dd,
 double rowCount)
                 throws StandardException

Optimize any subqueries that haven't been optimized any where else. This is useful for a RowResultSetNode as a derived table because it doesn't get optimized otherwise.

Throws:

StandardException - Thrown on error

tellRowOrderingAboutConstantColumns

protected void tellRowOrderingAboutConstantColumns(RowOrdering rowOrdering,
 OptimizablePredicateList predList)

Tell the given RowOrdering about any columns that are constant due to their being equality comparisons with constant expressions.

needsSpecialRCLBinding

boolean needsSpecialRCLBinding()

setOrigTableName

void setOrigTableName(TableName tableName)

Sets the original or unbound table name for this FromTable.

Parameters:

tableName - the unbound table name

getOrigTableName

TableName getOrigTableName()

Gets the original or unbound table name for this FromTable. The tableName field can be changed due to synonym resolution. Use this method to retrieve the actual unbound tablename.

Returns:

TableName the original or unbound tablename

setMergeTableID

void setMergeTableID(int mergeTableID)

set the merge table id

getMergeTableID

int getMergeTableID()

get the merge table id

acceptChildren

void acceptChildren(Visitor v)
             throws StandardException

Description copied from class: ResultSetNode

Accept the visitor for all visitable children of this node.

Overrides:

acceptChildren in class ResultSetNode

Parameters:

v - the visitor

Throws:

StandardException - on error