org.apache.derby.impl.sql.compile

Class PredicateList

java.lang.Object

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

org.apache.derby.impl.sql.compile.QueryTreeNodeVector

org.apache.derby.impl.sql.compile.PredicateList

All Implemented Interfaces:

Node, OptimizablePredicateList, Visitable

public class PredicateList
extends QueryTreeNodeVector
implements OptimizablePredicateList

A PredicateList represents the list of top level predicates. Each top level predicate consists of an AndNode whose leftOperand is the top level predicate and whose rightOperand is true. It extends QueryTreeNodeVector.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	PredicateList.PredicateWrapper Inner class which helps statistics routines do their work.
private class	PredicateList.PredicateWrapperList Another inner class which is basically a List of Predicate Wrappers.

Field Summary

Fields

Modifier and Type	Field and Description
private int	numberOfQualifiers
private int	numberOfStartPredicates
private int	numberOfStopPredicates
private static int	QUALIFIER_NUM_CATEGORIES
private static int	QUALIFIER_ORDER_EQUALS
private static int	QUALIFIER_ORDER_NON_QUAL
private static int	QUALIFIER_ORDER_NOT_EQUALS
private static int	QUALIFIER_ORDER_OR_CLAUSE
private static int	QUALIFIER_ORDER_OTHER_RELOP

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor and Description
PredicateList()

Method Summary

Modifier and Type	Method and Description
void	addOptPredicate(OptimizablePredicate optPredicate) Add the given OptimizablePredicate to the end of this list.
void	addOptPredicate(OptimizablePredicate optPredicate, int position) Another flavor of addOptPredicate that inserts the given predicate at a given position.
void	addPredicate(Predicate predicate) Add a Predicate to the list.
void	adjustForSortElimination(RequiredRowOrdering ordering) Walk through the predicates in this list and make any adjustments that are required to allow for proper handling of an ORDER BY clause.
(package private) boolean	allPushable() Check if all of the predicates in the list are pushable.
(package private) boolean	allReference(FromBaseTable fbt) Check if all the predicates reference a given FromBaseTable.
private void	calculateWeight(PredicateList.PredicateWrapperList[] pwList, int numUsefulPredicates)
void	categorize() Categorize the predicates in the list.
(package private) void	checkTopPredicatesForEqualsConditions(int tableNumber, boolean[] eqOuterCols, int[] tableNumbers, JBitSet[] tableColMap, boolean resultColTable) Update the array of columns in = conditions with constants or correlation or join columns.
private int	chooseLongestMatch(PredicateList.PredicateWrapperList[] predArray, java.util.List ret, int numWorkingPredicates) choose the statistic which has the maximum match with the predicates.
void	classify(Optimizable optTable, ConglomerateDescriptor cd) Classify the predicates in this list according to the given table and conglomerate.
(package private) boolean	constantColumn(ColumnReference colRef)
void	copyPredicatesToOtherList(OptimizablePredicateList otherList) Non-destructive copy of all of the predicates from this list to the other list.
private void	countScanFlags()
(package private) void	decrementLevel(FromList fromList, int decrement) Decrement the level of any CRs from the subquery's FROM list that are interesting to transitive closure.
void	eliminateBooleanTrueAndBooleanTrue() Eliminate predicates of the form: AndNode / \ true BooleanConstantNode true BooleanConstantNode This is useful when checking for a NOP PRN as the Like transformation on c1 like 'ASDF%' can leave one of these predicates in the list.
private void	finishKey(ExpressionClassBuilder acb, MethodBuilder mb, MethodBuilder exprFun, LocalField rowField) Finish generating a start or stop key
private LocalField	generateIndexableRow(ExpressionClassBuilder acb, int numberOfColumns) Generate the indexable row for a start key or stop key.
protected void	generateInListValues(ExpressionClassBuilder acb, MethodBuilder mb) If there is an IN-list probe predicate in this list then generate the corresponding IN-list values as a DataValueDescriptor array, to be used for probing at execution time.
void	generateQualifiers(ExpressionClassBuilderInterface acbi, MethodBuilder mb, Optimizable optTable, boolean absolute) Generate the qualifiers for a scan.
private void	generateSetColumn(ExpressionClassBuilder acb, MethodBuilder exprFun, int columnNumber, Predicate pred, Optimizable optTable, LocalField rowField, boolean isStartKey) Generate the code to set the value from a predicate in an index column.
private void	generateSingleQualifierCode(MethodBuilder consMB, Optimizable optTable, boolean absolute, ExpressionClassBuilder acb, RelationalOperator or_node, LocalField qualField, int array_idx_1, int array_idx_2)
void	generateStartKey(ExpressionClassBuilderInterface acbi, MethodBuilder mb, Optimizable optTable) Generate the start key for a heap or index scan.
void	generateStopKey(ExpressionClassBuilderInterface acbi, MethodBuilder mb, Optimizable optTable) Generate the stop key for a heap or index scan.
OptimizablePredicate	getOptPredicate(int index) Return the nth OptimizablePredicate in the list.
(package private) PredicateList	getPushablePredicates(JBitSet referencedTableMap) Build a list of pushable predicates, if any, that satisfy the referencedTableMap.
int	hasEqualityPredicateOnOrderedColumn(Optimizable optTable, int columnNumber, boolean isNullOkay) Check into the predicate list if the passed column has an equijoin predicate on it.
boolean	hasOptimizableEqualityPredicate(Optimizable optTable, int columnNumber, boolean isNullOkay) Is there an optimizable equality predicate on the specified column?
boolean	hasOptimizableEquijoin(Optimizable optTable, int columnNumber) Is there an optimizable equijoin on the specified column?
private static boolean	isConstantOrParameterNode(ValueNode node) Check if a node is representing a constant or a parameter.
boolean	isRedundantPredicate(int predNum) Return whether or not the specified entry in the list is a redundant predicate.
(package private) void	joinClauseTransitiveClosure(int numTables, FromList fromList, CompilerContext cc) Perform transitive closure on join clauses.
void	markAllPredicatesQualifiers() Mark all of the predicates as Qualifiers and set the numberOfQualifiers to reflect this.
(package private) void	markReferencedColumns() Mark all of the RCs and the RCs in their RC/VCN chain referenced in the predicate list as referenced.
private void	orderQualifiers()
private void	orderUsefulPredicates(Optimizable optTable, ConglomerateDescriptor cd, boolean pushPreds, boolean nonMatchingIndexScan, boolean coveringIndexScan)
(package private) void	pullExpressions(int numTables, ValueNode searchClause) Break apart the search clause into matching a PredicateList where each top level predicate is a separate element in the list.
(package private) void	pushExpressionsIntoSelect(SelectNode select, boolean copyPredicate) Push all predicates, which can be pushed, into the underlying select.
void	pushUsefulPredicates(Optimizable optTable) Determine which predicates in this list are useful for limiting the scan on the given table using its best conglomerate.
void	putOptimizableEqualityPredicateFirst(Optimizable optTable, int columnNumber) Find the optimizable equality predicate on the specified column and make it the first predicate in this list.
void	remapColumnReferencesToExpressions() Remap all ColumnReferences in this tree to be clones of the underlying expression.
void	removeOptPredicate(int predCtr) Remove the OptimizablePredicate at the specified index (0-based) from the list.
void	removeOptPredicate(OptimizablePredicate pred) Another version of removeOptPredicate that takes the Predicate to be removed, rather than the position of the Predicate.
(package private) void	removeRedundantPredicates() Remove redundant predicates.
ValueNode	restoreConstantPredicates() Rebuild a constant expression tree from the remaining constant predicates and delete those entries from the PredicateList.
ValueNode	restorePredicates() Rebuild an expression tree from the remaining predicates and delete those entries from the PredicateList.
boolean	sameStartStopPosition() Can we use the same key for both the start and stop key.
(package private) void	searchClauseTransitiveClosure(int numTables, boolean hashJoinSpecified) Perform transitive closure on search clauses.
double	selectivity(Optimizable optTable) calculate the selectivity for a set of predicates.
private double	selectivityNoStatistics(Optimizable optTable) Compute selectivity the old fashioned way.
void	setPredicatesAndProperties(OptimizablePredicateList otherList) Sets the given list to have the same elements as this one, and the same properties as this one (number of qualifiers and start and stop predicates.
int	startOperator(Optimizable optTable) Get the start operator for the given Optimizable for a heap or index scan.
int	stopOperator(Optimizable optTable) Get the stop operator for the given Optimizable for a heap or index scan.
void	transferAllPredicates(OptimizablePredicateList otherList) Transfer all the predicates from this list to the given list.
protected void	transferNonQualifiers(Optimizable optTable, PredicateList otherPL) Transfer the non-qualifiers from this predicate list to the specified predicate list.
void	transferPredicates(OptimizablePredicateList otherList, JBitSet referencedTableMap, Optimizable table) Transfer the predicates whose referenced set is contained by the specified referencedTableMap from this list to the other list.
boolean	useful(Optimizable optTable, ConglomerateDescriptor cd) Return true if this predicate list is useful for limiting the scan on the given table using the given conglomerate.
void	xorReferencedSet(JBitSet fromMap) XOR fromMap with the referenced table map in every remaining Predicate in the list.

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNodeVector

acceptChildren, addElement, destructiveAppend, elementAt, indexOf, insertElementAt, nondestructiveAppend, printSubNodes, remove, removeAllElements, removeElement, removeElementAt, setElementAt, size

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

accept, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, stackPrint, toString, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.iapi.sql.compile.OptimizablePredicateList

size

Field Detail

numberOfStartPredicates

private int numberOfStartPredicates

numberOfStopPredicates

private int numberOfStopPredicates

numberOfQualifiers

private int numberOfQualifiers

QUALIFIER_ORDER_EQUALS

private static final int QUALIFIER_ORDER_EQUALS

See Also:

Constant Field Values

QUALIFIER_ORDER_OTHER_RELOP

private static final int QUALIFIER_ORDER_OTHER_RELOP

See Also:

Constant Field Values

QUALIFIER_ORDER_NOT_EQUALS

private static final int QUALIFIER_ORDER_NOT_EQUALS

See Also:

Constant Field Values

QUALIFIER_ORDER_NON_QUAL

private static final int QUALIFIER_ORDER_NON_QUAL

See Also:

Constant Field Values

QUALIFIER_ORDER_OR_CLAUSE

private static final int QUALIFIER_ORDER_OR_CLAUSE

See Also:

Constant Field Values

QUALIFIER_NUM_CATEGORIES

private static final int QUALIFIER_NUM_CATEGORIES

See Also:

Constant Field Values

Constructor Detail

PredicateList

public PredicateList()

Method Detail

getOptPredicate

public OptimizablePredicate getOptPredicate(int index)

Description copied from interface: OptimizablePredicateList

Return the nth OptimizablePredicate in the list.

Specified by:

getOptPredicate in interface OptimizablePredicateList

Parameters:

index - "index" (0 based) into the list.

Returns:

OptimizablePredicate The nth OptimizablePredicate in the list.

See Also:

OptimizablePredicateList.getOptPredicate(int)

removeOptPredicate

public final void removeOptPredicate(int predCtr)
                              throws StandardException

Description copied from interface: OptimizablePredicateList

Remove the OptimizablePredicate at the specified index (0-based) from the list.

Specified by:

removeOptPredicate in interface OptimizablePredicateList

Parameters:

predCtr - The index.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.removeOptPredicate(int)

removeOptPredicate

public final void removeOptPredicate(OptimizablePredicate pred)

Another version of removeOptPredicate that takes the Predicate to be removed, rather than the position of the Predicate. This is not part any interface (yet).

addOptPredicate

public void addOptPredicate(OptimizablePredicate optPredicate)

Description copied from interface: OptimizablePredicateList

Add the given OptimizablePredicate to the end of this list.

Specified by:

addOptPredicate in interface OptimizablePredicateList

Parameters:

optPredicate - The predicate to add

See Also:

OptimizablePredicateList.addOptPredicate(org.apache.derby.iapi.sql.compile.OptimizablePredicate)

addOptPredicate

public void addOptPredicate(OptimizablePredicate optPredicate,
                            int position)

Another flavor of addOptPredicate that inserts the given predicate at a given position. This is not yet part of any interface.

useful

public boolean useful(Optimizable optTable,
                      ConglomerateDescriptor cd)
               throws StandardException

Description copied from interface: OptimizablePredicateList

Return true if this predicate list is useful for limiting the scan on the given table using the given conglomerate.

Specified by:

useful in interface OptimizablePredicateList

Parameters:

optTable - An Optimizable for the table in question

cd - A ConglomerateDescriptor for the conglomerate in question

Returns:

true if this predicate list can limit the scan

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.useful(org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.dictionary.ConglomerateDescriptor)

pushUsefulPredicates

public void pushUsefulPredicates(Optimizable optTable)
                          throws StandardException

Description copied from interface: OptimizablePredicateList

Determine which predicates in this list are useful for limiting the scan on the given table using its best conglomerate. Remove those predicates from this list and push them down to the given Optimizable table. The predicates are pushed down in the order of the index columns that they qualify. Also, the predicates are "marked" as start predicates, stop predicates, or qualifier predicates. Finally, the start and stop operators are set in the given Optimizable.

Specified by:

pushUsefulPredicates in interface OptimizablePredicateList

Parameters:

optTable - An Optimizable for the table in question

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.pushUsefulPredicates(org.apache.derby.iapi.sql.compile.Optimizable)

classify

public void classify(Optimizable optTable,
                     ConglomerateDescriptor cd)
              throws StandardException

Description copied from interface: OptimizablePredicateList

Classify the predicates in this list according to the given table and conglomerate. Each predicate can be a start key, stop key, and/or qualifier, or it can be none of the above. This method also orders the predicates to match the order of the columns in a keyed conglomerate. No ordering is done for heaps.

Specified by:

classify in interface OptimizablePredicateList

Parameters:

optTable - The Optimizable table for which to classify the predicates in this list.

cd - The ConglomerateDescriptor for which to classify the predicates in this list.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.classify(org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.dictionary.ConglomerateDescriptor)

markAllPredicatesQualifiers

public void markAllPredicatesQualifiers()

Description copied from interface: OptimizablePredicateList

Mark all of the predicates as Qualifiers and set the numberOfQualifiers to reflect this. This is useful for hash joins where all of the predicates in the list to be evaluated during the probe into the hash table on a next are qualifiers.

Specified by:

markAllPredicatesQualifiers in interface OptimizablePredicateList

See Also:

OptimizablePredicateList.markAllPredicatesQualifiers()

hasEqualityPredicateOnOrderedColumn

public int hasEqualityPredicateOnOrderedColumn(Optimizable optTable,
                                               int columnNumber,
                                               boolean isNullOkay)
                                        throws StandardException

Description copied from interface: OptimizablePredicateList

Check into the predicate list if the passed column has an equijoin predicate on it.

Specified by:

hasEqualityPredicateOnOrderedColumn in interface OptimizablePredicateList

Returns:

the position of the predicate in the list which corresponds to the equijoin. If no quijoin predicate found, then the return value will be -1

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.hasEqualityPredicateOnOrderedColumn(org.apache.derby.iapi.sql.compile.Optimizable, int, boolean)

hasOptimizableEqualityPredicate

public boolean hasOptimizableEqualityPredicate(Optimizable optTable,
                                               int columnNumber,
                                               boolean isNullOkay)
                                        throws StandardException

Description copied from interface: OptimizablePredicateList

Is there an optimizable equality predicate on the specified column?

Specified by:

hasOptimizableEqualityPredicate in interface OptimizablePredicateList

Parameters:

optTable - The optimizable the column comes from.

columnNumber - The column number within the base table.

isNullOkay - boolean, whether or not the IS NULL operator satisfies the search

Returns:

Whether or not there is an optimizable equality predicate on the specified column.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.hasOptimizableEqualityPredicate(org.apache.derby.iapi.sql.compile.Optimizable, int, boolean)

hasOptimizableEquijoin

public boolean hasOptimizableEquijoin(Optimizable optTable,
                                      int columnNumber)
                               throws StandardException

Description copied from interface: OptimizablePredicateList

Is there an optimizable equijoin on the specified column?

Specified by:

hasOptimizableEquijoin in interface OptimizablePredicateList

Parameters:

optTable - The optimizable the column comes from.

columnNumber - The column number within the base table.

Returns:

Whether or not there is an optimizable equijoin on the specified column.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.hasOptimizableEquijoin(org.apache.derby.iapi.sql.compile.Optimizable, int)

putOptimizableEqualityPredicateFirst

public void putOptimizableEqualityPredicateFirst(Optimizable optTable,
                                                 int columnNumber)
                                          throws StandardException

Description copied from interface: OptimizablePredicateList

Find the optimizable equality predicate on the specified column and make it the first predicate in this list. This is useful for hash joins where Qualifier[0] is assumed to be on the hash key.

Specified by:

putOptimizableEqualityPredicateFirst in interface OptimizablePredicateList

Parameters:

optTable - The optimizable the column comes from.

columnNumber - The column number within the base table.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.putOptimizableEqualityPredicateFirst(org.apache.derby.iapi.sql.compile.Optimizable, int)

orderUsefulPredicates

private void orderUsefulPredicates(Optimizable optTable,
                                   ConglomerateDescriptor cd,
                                   boolean pushPreds,
                                   boolean nonMatchingIndexScan,
                                   boolean coveringIndexScan)
                            throws StandardException

Throws:

StandardException

addPredicate

public void addPredicate(Predicate predicate)
                  throws StandardException

Add a Predicate to the list.

Parameters:

predicate - A Predicate to add to the list

Throws:

StandardException - Thrown on error

transferNonQualifiers

protected void transferNonQualifiers(Optimizable optTable,
                                     PredicateList otherPL)
                              throws StandardException

Transfer the non-qualifiers from this predicate list to the specified predicate list. This is useful for arbitrary hash join, where we need to separate the 2 as the qualifiers get applied when probing the hash table and the non-qualifiers get * applied afterwards.

Parameters:

optTable - The optimizable that we want qualifiers for

otherPL - ParameterList for non-qualifiers

Throws:

StandardException - Thrown on error

categorize

public void categorize()
                throws StandardException

Categorize the predicates in the list. Initially, this means building a bit map of the referenced tables for each predicate.

Throws:

StandardException - Thrown on error

eliminateBooleanTrueAndBooleanTrue

public void eliminateBooleanTrueAndBooleanTrue()

Eliminate predicates of the form: AndNode / \ true BooleanConstantNode true BooleanConstantNode This is useful when checking for a NOP PRN as the Like transformation on c1 like 'ASDF%' can leave one of these predicates in the list.

restoreConstantPredicates

public ValueNode restoreConstantPredicates()
                                    throws StandardException

Rebuild a constant expression tree from the remaining constant predicates and delete those entries from the PredicateList. The rightOperand of every top level AndNode is always a true BooleanConstantNode, so we can blindly overwrite that pointer. Optimizations: We take this opportunity to eliminate: AndNode / \ true BooleanConstantNode true BooleanConstantNode We remove the AndNode if the predicate list is a single AndNode: AndNode / \ LeftOperand RightOperand becomes: LeftOperand If the leftOperand of any AndNode is False, then the entire expression will be False. The expression simple becomes: false BooleanConstantNode

Returns:

ValueNode The rebuilt expression tree.

Throws:

StandardException

restorePredicates

public ValueNode restorePredicates()
                            throws StandardException

Rebuild an expression tree from the remaining predicates and delete those entries from the PredicateList. The rightOperand of every top level AndNode is always a true BooleanConstantNode, so we can blindly overwrite that pointer. Optimizations: We take this opportunity to eliminate: AndNode / \ true BooleanConstantNode true BooleanConstantNode We remove the AndNode if the predicate list is a single AndNode: AndNode / \ LeftOperand RightOperand becomes: LeftOperand If the leftOperand of any AndNode is False, then the entire expression will be False. The expression simple becomes: false BooleanConstantNode

Returns:

ValueNode The rebuilt expression tree.

Throws:

StandardException

remapColumnReferencesToExpressions

public void remapColumnReferencesToExpressions()
                                        throws StandardException

Remap all ColumnReferences in this tree to be clones of the underlying expression.

Throws:

StandardException - Thrown on error

pullExpressions

void pullExpressions(int numTables,
                     ValueNode searchClause)
              throws StandardException

Break apart the search clause into matching a PredicateList where each top level predicate is a separate element in the list. Build a bit map to represent the FromTables referenced within each top level predicate. NOTE: We want the rightOperand of every AndNode to be true, in order to simplify the algorithm for putting the predicates back into the tree. (As we put an AndNode back into the tree, we can ignore it's rightOperand.)

Parameters:

numTables - Number of tables in the DML Statement

searchClause - The search clause to operate on.

Throws:

StandardException - Thrown on error

xorReferencedSet

public void xorReferencedSet(JBitSet fromMap)

XOR fromMap with the referenced table map in every remaining Predicate in the list. This is useful when pushing down multi-table predicates.

Parameters:

fromMap - The JBitSet to XOR with.

countScanFlags

private void countScanFlags()

isConstantOrParameterNode

private static boolean isConstantOrParameterNode(ValueNode node)

Check if a node is representing a constant or a parameter.

Parameters:

node - the node to check

Returns:

true if the node is a constant or a parameter, false otherwise

pushExpressionsIntoSelect

void pushExpressionsIntoSelect(SelectNode select,
                               boolean copyPredicate)
                        throws StandardException

Push all predicates, which can be pushed, into the underlying select. A predicate can be pushed into an underlying select if the source of every ColumnReference in the predicate is itself a ColumnReference. This is useful when attempting to push predicates into non-flattenable views or derived tables or into unions.

Parameters:

select - The underlying SelectNode.

copyPredicate - Whether to make a copy of the predicate before pushing

Throws:

StandardException - Thrown on error

markReferencedColumns

void markReferencedColumns()
                    throws StandardException

Mark all of the RCs and the RCs in their RC/VCN chain referenced in the predicate list as referenced.

Throws:

StandardException - Thrown on error

checkTopPredicatesForEqualsConditions

void checkTopPredicatesForEqualsConditions(int tableNumber,
                                           boolean[] eqOuterCols,
                                           int[] tableNumbers,
                                           JBitSet[] tableColMap,
                                           boolean resultColTable)
                                    throws StandardException

Update the array of columns in = conditions with constants or correlation or join columns. This is useful when doing subquery flattening on the basis of an equality condition.

Parameters:

tableNumber - The tableNumber of the table from which the columns of interest come from.

eqOuterCols - Array of booleans for noting which columns are in = predicates with constants or correlation columns.

tableNumbers - Array of table numbers in this query block.

resultColTable - tableNumber is the table the result columns are coming from

Throws:

StandardException - Thrown on error

allPushable

boolean allPushable()

Check if all of the predicates in the list are pushable.

Returns:

Whether or not all of the predicates in the list are pushable.

allReference

boolean allReference(FromBaseTable fbt)

Check if all the predicates reference a given FromBaseTable.

Parameters:

fbt - the FromBaseTable to check for

Returns:

true if the table is referenced by all predicates, false otherwise

getPushablePredicates

PredicateList getPushablePredicates(JBitSet referencedTableMap)
                             throws StandardException

Build a list of pushable predicates, if any, that satisfy the referencedTableMap.

Parameters:

referencedTableMap - The referenced table map

Returns:

A list of pushable predicates, if any, that satisfy the referencedTableMap.

Throws:

StandardException - Thrown on error

decrementLevel

void decrementLevel(FromList fromList,
                    int decrement)

Decrement the level of any CRs from the subquery's FROM list that are interesting to transitive closure.

Parameters:

fromList - The subquery's FROM list.

decrement - Decrement size.

joinClauseTransitiveClosure

void joinClauseTransitiveClosure(int numTables,
                                 FromList fromList,
                                 CompilerContext cc)
                          throws StandardException

Perform transitive closure on join clauses. For each table in the query, we build a list of equijoin clauses of the form: <=> Each join clause is put on 2 lists since it joins 2 tables. We then walk the array of lists. We first walk it as the outer list. For each equijoin predicate, we assign an equivalence class if it does not yet have one. We then walk the predicate list (as middle) for the other table, searching for other equijoins with the middle table number and column number. All such predicates are assigned the same equivalence class. We then walk the predicate list (as inner) for the other side of the middle predicate to see if we can find an equijoin between outer and inner. If so, then we simply assign it to the same equivalence class. If not, then we add the new equijoin clause. Note that an equijoin predicate between two tables CANNOT be used for transitive closure, if either of the tables is in the fromlist for NOT EXISTS. In that case, the join predicate actually specifies that the rows from the indicated table must NOT exist, and therefore those non-existent rows cannot be transitively joined to the other matching tables. See DERBY-3033 for a description of a situation in which this actually arises.

Parameters:

numTables - The number of tables in the query

fromList - The FromList in question.

cc - The CompilerContext to use

Throws:

StandardException - Thrown on error

searchClauseTransitiveClosure

void searchClauseTransitiveClosure(int numTables,
                                   boolean hashJoinSpecified)
                            throws StandardException

Perform transitive closure on search clauses. We build a list of search clauses of the form: [] We also build a list of equijoin conditions of form: = where both columns are from different tables in the same query block. For each search clause in the list, we search the equijoin list to see if there is an equijoin clause on the same column. If so, then we search the search clause list for a search condition on the column being joined against with the same relation operator and constant. If a match is found, then there is no need to add a new predicate. Otherwise, we add a new search condition on the column being joined with. In either case, if the relational operator in the search clause is an "=" then we mark the equijoin clause as being redundant. Redundant equijoin clauses will be removed at the end of the search as they are * unnecessary.

Parameters:

numTables - The number of tables in the query

hashJoinSpecified - Whether or not user specified a hash join

Throws:

StandardException - Thrown on error

removeRedundantPredicates

void removeRedundantPredicates()

Remove redundant predicates. A redundant predicate has an equivalence class (!= -1) and there are other predicates in the same equivalence class after it in the list. (Actually, we remove all of the predicates in the same equivalence class that appear after this one.)

transferPredicates

public void transferPredicates(OptimizablePredicateList otherList,
                               JBitSet referencedTableMap,
                               Optimizable table)
                        throws StandardException

Description copied from interface: OptimizablePredicateList

Transfer the predicates whose referenced set is contained by the specified referencedTableMap from this list to the other list. This is useful when splitting out a set of predicates from a larger set, like when generating a HashScanResultSet.

Specified by:

transferPredicates in interface OptimizablePredicateList

Parameters:

otherList - The predicateList to xfer to

referencedTableMap - The table map to check against

table - The table to order the new predicates against

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.transferPredicates(org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.util.JBitSet, org.apache.derby.iapi.sql.compile.Optimizable)

transferAllPredicates

public void transferAllPredicates(OptimizablePredicateList otherList)
                           throws StandardException

Description copied from interface: OptimizablePredicateList

Transfer all the predicates from this list to the given list.

Specified by:

transferAllPredicates in interface OptimizablePredicateList

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.transferAllPredicates(org.apache.derby.iapi.sql.compile.OptimizablePredicateList)

copyPredicatesToOtherList

public void copyPredicatesToOtherList(OptimizablePredicateList otherList)
                               throws StandardException

Description copied from interface: OptimizablePredicateList

Non-destructive copy of all of the predicates from this list to the other list. This is useful when splitting out a set of predicates from a larger set, like when generating a HashScanResultSet.

Specified by:

copyPredicatesToOtherList in interface OptimizablePredicateList

Parameters:

otherList - The predicateList to xfer to

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.copyPredicatesToOtherList(org.apache.derby.iapi.sql.compile.OptimizablePredicateList)

isRedundantPredicate

public boolean isRedundantPredicate(int predNum)

Description copied from interface: OptimizablePredicateList

Return whether or not the specified entry in the list is a redundant predicate. This is useful for selectivity calculations because we do not want redundant predicates included in the selectivity calculation.

Specified by:

isRedundantPredicate in interface OptimizablePredicateList

Parameters:

predNum - The entry in the list

Returns:

Whether or not the specified entry in the list is a redundant predicate.

See Also:

OptimizablePredicateList.isRedundantPredicate(int)

setPredicatesAndProperties

public void setPredicatesAndProperties(OptimizablePredicateList otherList)
                                throws StandardException

Description copied from interface: OptimizablePredicateList

Sets the given list to have the same elements as this one, and the same properties as this one (number of qualifiers and start and stop predicates.

Specified by:

setPredicatesAndProperties in interface OptimizablePredicateList

Parameters:

otherList - The list to set the same as this one.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.setPredicatesAndProperties(org.apache.derby.iapi.sql.compile.OptimizablePredicateList)

startOperator

public int startOperator(Optimizable optTable)

Description copied from interface: OptimizablePredicateList

Get the start operator for the given Optimizable for a heap or index scan.

Specified by:

startOperator in interface OptimizablePredicateList

See Also:

OptimizablePredicateList.startOperator(org.apache.derby.iapi.sql.compile.Optimizable)

generateStopKey

public void generateStopKey(ExpressionClassBuilderInterface acbi,
                            MethodBuilder mb,
                            Optimizable optTable)
                     throws StandardException

Description copied from interface: OptimizablePredicateList

Generate the stop key for a heap or index scan.

Specified by:

generateStopKey in interface OptimizablePredicateList

Parameters:

acbi - The ExpressionClassBuilderInterface for the class we're building

mb - the method the generated code is to go into

optTable - The Optimizable table the stop key is for

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.generateStopKey(org.apache.derby.iapi.sql.compile.ExpressionClassBuilderInterface, org.apache.derby.iapi.services.compiler.MethodBuilder, org.apache.derby.iapi.sql.compile.Optimizable)

stopOperator

public int stopOperator(Optimizable optTable)

Description copied from interface: OptimizablePredicateList

Get the stop operator for the given Optimizable for a heap or index scan.

Specified by:

stopOperator in interface OptimizablePredicateList

See Also:

OptimizablePredicateList.stopOperator(org.apache.derby.iapi.sql.compile.Optimizable)

generateSingleQualifierCode

private void generateSingleQualifierCode(MethodBuilder consMB,
                                         Optimizable optTable,
                                         boolean absolute,
                                         ExpressionClassBuilder acb,
                                         RelationalOperator or_node,
                                         LocalField qualField,
                                         int array_idx_1,
                                         int array_idx_2)
                                  throws StandardException

Throws:

StandardException

generateInListValues

protected void generateInListValues(ExpressionClassBuilder acb,
                                    MethodBuilder mb)
                             throws StandardException

If there is an IN-list probe predicate in this list then generate the corresponding IN-list values as a DataValueDescriptor array, to be used for probing at execution time. Also generate a boolean value indicating whether or not the values are already in sorted order. Assumption is that by the time we get here there is at most one IN-list probe predicate in this list.

Parameters:

acb - The ActivationClassBuilder for the class we're building

mb - The MethodBuilder for the method we're building

Throws:

StandardException

generateQualifiers

public void generateQualifiers(ExpressionClassBuilderInterface acbi,
                               MethodBuilder mb,
                               Optimizable optTable,
                               boolean absolute)
                        throws StandardException

Description copied from interface: OptimizablePredicateList

Generate the qualifiers for a scan. This method generates an array of Qualifiers, and fills them in with calls to the factory method for generating Qualifiers in the constructor for the activation. It stores the array of Qualifiers in a field in the activation, and returns a reference to that field. If there are no qualifiers, it initializes the array of Qualifiers to null.

Specified by:

generateQualifiers in interface OptimizablePredicateList

Parameters:

acbi - The ExpressionClassBuilderInterface for the class we are building

mb - The method the generated code is going into

optTable - The Optimizable table the Qualifiers are on

absolute - Generate absolute column positions if true, else relative column positions (within the underlying row)

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.generateQualifiers(org.apache.derby.iapi.sql.compile.ExpressionClassBuilderInterface, org.apache.derby.iapi.services.compiler.MethodBuilder, org.apache.derby.iapi.sql.compile.Optimizable, boolean)

orderQualifiers

private void orderQualifiers()

generateStartKey

public void generateStartKey(ExpressionClassBuilderInterface acbi,
                             MethodBuilder mb,
                             Optimizable optTable)
                      throws StandardException

Description copied from interface: OptimizablePredicateList

Generate the start key for a heap or index scan.

Specified by:

generateStartKey in interface OptimizablePredicateList

Parameters:

acbi - The ExpressionClassBuilderInterface for the class we're building

mb - The method the generated code is to go into

optTable - The Optimizable table the start key is for

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.generateStartKey(org.apache.derby.iapi.sql.compile.ExpressionClassBuilderInterface, org.apache.derby.iapi.services.compiler.MethodBuilder, org.apache.derby.iapi.sql.compile.Optimizable)

sameStartStopPosition

public boolean sameStartStopPosition()
                              throws StandardException

Description copied from interface: OptimizablePredicateList

Can we use the same key for both the start and stop key. This is possible when doing an exact match on an index where there are no other sargable predicates.

Specified by:

sameStartStopPosition in interface OptimizablePredicateList

Returns:

Whether or not we can use the same key for both the start and stop key.

Throws:

StandardException - Thrown on error

See Also:

OptimizablePredicateList.sameStartStopPosition()

generateIndexableRow

private LocalField generateIndexableRow(ExpressionClassBuilder acb,
                                        int numberOfColumns)

Generate the indexable row for a start key or stop key.

Parameters:

acb - The ActivationClassBuilder for the class we're building

numberOfColumns - The number of columns in the key

Returns:

The field that holds the indexable row

generateSetColumn

private void generateSetColumn(ExpressionClassBuilder acb,
                               MethodBuilder exprFun,
                               int columnNumber,
                               Predicate pred,
                               Optimizable optTable,
                               LocalField rowField,
                               boolean isStartKey)
                        throws StandardException

Generate the code to set the value from a predicate in an index column.

Parameters:

acb - The ActivationClassBuilder for the class we're building

exprFun - The MethodBuilder for the method we're building

columnNumber - The position number of the column we're setting the value in (zero-based)

pred - The Predicate with the value to put in the index column

optTable - The Optimizable table the column is in

rowField - The field that holds the indexable row

isStartKey - Are we generating start or stop key? This information is useful for "in"'s dynamic start/stop key, bug 3858

Throws:

StandardException - Thrown on error

finishKey

private void finishKey(ExpressionClassBuilder acb,
                       MethodBuilder mb,
                       MethodBuilder exprFun,
                       LocalField rowField)

Finish generating a start or stop key

Parameters:

acb - The ActivationClassBuilder for the class we're building

exprFun - The MethodBuilder for the method we're building

rowField - The name of the field that holds the indexable row

constantColumn

boolean constantColumn(ColumnReference colRef)

adjustForSortElimination

public void adjustForSortElimination(RequiredRowOrdering ordering)
                              throws StandardException

Description copied from interface: OptimizablePredicateList

Walk through the predicates in this list and make any adjustments that are required to allow for proper handling of an ORDER BY clause.

Specified by:

adjustForSortElimination in interface OptimizablePredicateList

Throws:

StandardException

See Also:

Currently this method only accounts for IN list multi-probing predicates (DERBY-3279).

selectivity

public double selectivity(Optimizable optTable)
                   throws StandardException

Description copied from interface: OptimizablePredicateList

calculate the selectivity for a set of predicates. If statistics exist for the predicates this method uses the statistics. If statistics do not exist, then simply call selectivity for each of the predicates and return the result.

Specified by:

selectivity in interface OptimizablePredicateList

Parameters:

optTable - the Optimizable that the predicate list restricts.

Throws:

StandardException

See Also:

OptimizablePredicateList.selectivity(org.apache.derby.iapi.sql.compile.Optimizable)

calculateWeight

private void calculateWeight(PredicateList.PredicateWrapperList[] pwList,
                             int numUsefulPredicates)

chooseLongestMatch

private int chooseLongestMatch(PredicateList.PredicateWrapperList[] predArray,
                               java.util.List ret,
                               int numWorkingPredicates)

choose the statistic which has the maximum match with the predicates. value is returned in ret.

selectivityNoStatistics

private double selectivityNoStatistics(Optimizable optTable)
                                throws StandardException

Compute selectivity the old fashioned way.

Throws:

StandardException