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

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.ResultSetNode

All Implemented Interfaces:

Node, Visitable

Direct Known Subclasses:

FromTable, MaterializeSubqueryNode, SelectNode

public abstract class ResultSetNode
extends QueryTreeNode

A ResultSetNode represents a result set, that is, a set of rows. It is analogous to a ResultSet in the LanguageModuleExternalInterface. In fact, code generation for a a ResultSetNode will create a "new" call to a constructor for a ResultSet.

Field Summary

(package private) CostEstimate	costEstimate
(package private) boolean	cursorTargetTable
(package private) CostEstimate	finalCostEstimate
(package private) boolean	insertSource
(package private) Optimizer	optimizer
(package private) JBitSet	referencedTableMap
(package private) ResultColumnList	resultColumns
(package private) int	resultSetNumber
(package private) CostEstimate	scratchCostEstimate
(package private) boolean	statementResultSet

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

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, isPrivilegeCollectionRequired

Constructor Summary

ResultSetNode()

Method Summary

(package private) void	acceptChildren(Visitor v) Accept the visitor for all visitable children of this node.
ResultSetNode	addNewPredicate(Predicate predicate) Add a new predicate to the list.
(package private) void	adjustForSortElimination() Notify the underlying result set tree that the optimizer has chosen to "eliminate" a sort.
(package private) void	adjustForSortElimination(RequiredRowOrdering rowOrdering) Same goal as adjustForSortElimination above, but this version takes a RequiredRowOrdering to allow nodes to adjust based on the ORDER BY clause, if needed.
void	assignResultSetNumber() Assign the next resultSetNumber to the resultSetNumber in this ResultSetNode.
void	bindExpressions(FromList fromListParam) Bind the expressions in this ResultSetNode.
void	bindExpressionsWithTables(FromList fromListParam) Bind the expressions in this ResultSetNode if it has tables.
ResultSetNode	bindNonVTITables(DataDictionary dataDictionary, FromList fromListParam) Bind the non VTI tables in this ResultSetNode.
void	bindResultColumns(FromList fromListParam) Bind the result columns of this ResultSetNode when there is no base table to bind them to.
void	bindResultColumns(TableDescriptor targetTableDescriptor, FromVTI targetVTI, ResultColumnList targetColumnList, DMLStatementNode statement, FromList fromListParam) Bind the result columns for this ResultSetNode to a base table.
void	bindTargetExpressions(FromList fromListParam) Bind the expressions in the target list.
void	bindUntypedNullsToResultColumns(ResultColumnList rcl) Bind untyped nulls to the types in the given ResultColumnList.
ResultSetNode	bindVTITables(FromList fromListParam) Bind the VTI tables in this ResultSetNode.
ResultSetNode	changeAccessPath() The optimizer's decision on the access path for a result set may require the generation of extra result sets.
(package private) boolean	columnTypesAndLengthsMatch()
ResultSetNode	considerMaterialization(JBitSet outerTables) Consider materialization for this ResultSet tree if it is valid and cost effective (It is not valid if incorrect results would be returned.)
private ResultColumn	createGeneratedColumn(TableDescriptor targetTD, ColumnDescriptor colDesc) Create a ResultColumn for a column with a generation clause.
(package private) abstract void	decrementLevel(int decrement) Decrement (query block) level (0-based) for all of the tables in this ResultSet tree.
(package private) ResultSetNode	enhanceRCLForInsert(InsertNode target, boolean inOrder, int[] colMap) This ResultSet is the source for an Insert.
ResultSetNode	ensurePredicateList(int numTables) Ensure that the top of the RSN tree has a PredicateList.
void	fillInReferencedTableMap(JBitSet passedMap) Fill the referencedTableMap with this ResultSetNode.
boolean	flattenableInFromSubquery(FromList fromList) Evaluate whether or not the subquery in a FromSubquery is flattenable.
void	generateNormalizationResultSet(ActivationClassBuilder acb, MethodBuilder mb, int resultSetNumber, ResultDescription resultDescription) Generate the code for a NormalizeResultSet.
private ResultSetNode	generateProjectRestrictForInsert(InsertNode target, int[] colMap) Generate a ProjectRestrictNode to put on top of this node if it's the source for an insert, and the RCL needs reordering and/or addition of columns in order to match the target RCL.
void	generateResultSet(ExpressionClassBuilder acb, MethodBuilder mb) General logic shared by Core compilation and by the Replication Filter compiler.
private ResultColumn	genNewRCForInsert(TableDescriptor targetTD, FromVTI targetVTI, int columnNumber, DataDictionary dataDictionary) Generate the RC/expression for an unspecified column in an insert.
ResultSetNode	genProjectRestrict() Put a ProjectRestrictNode on top of this ResultSetNode.
protected ResultSetNode	genProjectRestrict(int numTables) Put a ProjectRestrictNode on top of each FromTable in the FromList.
(package private) ResultSetNode	genProjectRestrictForReordering() Get a parent ProjectRestrictNode above us.
ResultColumnList	getAllResultColumns(TableName allTableName) Expand "*" into a ResultColumnList with all of the columns in the table's result list.
CostEstimate	getCostEstimate() Get the CostEstimate for this ResultSetNode.
(package private) FromTable	getCursorTargetTable() return the target table of an updatable cursor result set.
CostEstimate	getFinalCostEstimate() Get the final CostEstimate for this ResultSetNode.
FromList	getFromList() Get the FromList.
protected FromTable	getFromTableByName(java.lang.String name, java.lang.String schemaName, boolean exactMatch) Determine whether or not the specified name is an exposed name in the current query block.
ResultColumn	getMatchingColumn(ColumnReference columnReference) Try to find a ResultColumn in the table represented by this FromTable that matches the name in the given ColumnReference.
protected CostEstimate	getNewCostEstimate() Get a cost estimate to use for this ResultSetNode.
protected Optimizer	getOptimizer(OptimizableList optList, OptimizablePredicateList predList, DataDictionary dataDictionary, RequiredRowOrdering requiredRowOrdering) Get an optimizer to use for this ResultSetNode.
protected OptimizerImpl	getOptimizerImpl() Get the optimizer for this result set.
(package private) ResultColumnList	getRCLForInsert(InsertNode target, int[] colMap) Generate an RCL that can replace the original RCL of this node to match the RCL of the target for the insert.
JBitSet	getReferencedTableMap() Get the referencedTableMap for this ResultSetNode
ResultColumnList	getResultColumns() Get the resultColumns for this ResultSetNode
int	getResultSetNumber() Get the resultSetNumber in this ResultSetNode.
boolean	isNotExists() Return whether or not the underlying ResultSet tree is for a NOT EXISTS join.
boolean	isOneRowResultSet() Return whether or not the underlying ResultSet tree will return a single row, at most.
(package private) boolean	isOrderedOn(ColumnReference[] crs, boolean permuteOrdering, java.util.List fbtVector) Return whether or not the underlying ResultSet tree is ordered on the specified columns.
(package private) boolean	isPossibleDistinctScan(java.util.Set distinctColumns) Is it possible to do a distinct scan on this ResultSet tree.
(package private) boolean	isUpdatableCursor(DataDictionary dd) Determine if this result set is updatable or not, for a cursor (i.e., is it a cursor-updatable select).
JBitSet	LOJgetReferencedTables(int numTables)
ResultDescription	makeResultDescription() Make a ResultDescription for use in a ResultSet.
(package private) ResultColumnDescriptor[]	makeResultDescriptors()
boolean	markAsCursorTargetTable() Mark this ResultSetNode as the target table of an updatable cursor.
(package private) void	markForDistinctScan() Mark the underlying scan as a distinct scan.
void	markStatementResultSet() This method is overridden to allow a resultset node to know if it is the one controlling the statement -- i.e., it is the outermost result set node for the statement.
ResultSetNode	modifyAccessPaths() Modify the access paths according to the decisions the optimizer made.
ResultSetNode	modifyAccessPaths(PredicateList predList) Modify the access paths according to the decisions the optimizer made.
(package private) void	notCursorTargetTable() Mark this ResultSetNode as *not* the target table of an updatable cursor.
(package private) void	notFlattenableJoin() Mark this node and its children as not being a flattenable join.
protected static int	numDistinctAggregates(java.util.List aggregateVector) Count the number of distinct aggregates in the list.
ResultSetNode	optimize(DataDictionary dataDictionary, PredicateList predicates, double outerRows) Optimize a ResultSetNode.
ValueNode	parseDefault(java.lang.String defaultText) Parse a default and turn it into a query tree.
boolean	performMaterialization(JBitSet outerTables) Return whether or not to materialize this ResultSet tree.
ResultSetNode	preprocess(int numTables, GroupByList gbl, FromList fromList) Preprocess a ResultSetNode - this currently means: o Generating a referenced table map for each ResultSetNode.
void	printSubNodes(int depth) Prints the sub-nodes of this object.
(package private) void	projectResultColumns() Find the unreferenced result columns and project them out.
(package private) void	pushOffsetFetchFirst(ValueNode offset, ValueNode fetchFirst, boolean hasJDBClimitClause) Push down the offset and fetch first parameters, if any.
(package private) void	pushOrderByList(OrderByList orderByList) Push the order by list down from the cursor node into its child result set so that the optimizer has all of the information that it needs to consider sort avoidance.
boolean	referencesTarget(java.lang.String name, boolean baseTable) Search to see if a query references the specifed table name.
void	rejectParameters() Check for (and reject) ?
void	rejectXMLValues() Check for (and reject) XML values directly under the ResultColumns.
void	renameGeneratedResultNames() Rename generated result column names as '1', '2' etc...
(package private) void	replaceOrForbidDefaults(TableDescriptor ttd, ResultColumnList tcl, boolean allowDefaults) Replace any DEFAULTs with the associated tree for the default if allowed, or flag (when inside top level set operator nodes).
(package private) boolean	returnsAtMostOneRow() Return whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics.
void	setInsertSource() Remember that this node is the source result set for an INSERT.
void	setReferencedTableMap(JBitSet newRTM) Set the referencedTableMap in this ResultSetNode
void	setResultColumns(ResultColumnList newRCL) Set the resultColumns in this ResultSetNode
ResultSetNode	setResultToBooleanTrueNode(boolean onlyConvertAlls) Set the result column for the subquery to a boolean true, Useful for transformations such as changing: where exists (select ... from ...)
(package private) void	setTableConstructorTypes(ResultColumnList typeColumns) Set the type of each parameter in the result column list for this table constructor.
(package private) boolean	subqueryReferencesTarget(java.lang.String name, boolean baseTable) Return whether or not this ResultSetNode contains a subquery with a reference to the specified target.
java.lang.String	toString() Convert this object to a String.
int	updateTargetLockMode() Get the lock mode for the target of an update statement (a delete or update).
void	verifySelectStarSubquery(FromList outerFromList, int subqueryType) Verify that a SELECT * is valid for this type of subquery.

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, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

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

Field Detail

resultSetNumber

int resultSetNumber

referencedTableMap

JBitSet referencedTableMap

resultColumns

ResultColumnList resultColumns

statementResultSet

boolean statementResultSet

cursorTargetTable

boolean cursorTargetTable

insertSource

boolean insertSource

costEstimate

CostEstimate costEstimate

scratchCostEstimate

CostEstimate scratchCostEstimate

optimizer

Optimizer optimizer

finalCostEstimate

CostEstimate finalCostEstimate

Constructor Detail

ResultSetNode

public ResultSetNode()

Method Detail

toString

public java.lang.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 QueryTreeNode

Returns:

This object as a String

printSubNodes

public void printSubNodes(int depth)

Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Overrides:

printSubNodes in class QueryTreeNode

Parameters:

depth - The depth of this node in the tree

getResultSetNumber

public int getResultSetNumber()

Get the resultSetNumber in this ResultSetNode. Expected to be set during generate().

Returns:

int The resultSetNumber.

getCostEstimate

public CostEstimate getCostEstimate()

Get the CostEstimate for this ResultSetNode.

Returns:

The CostEstimate for this ResultSetNode.

getFinalCostEstimate

public CostEstimate getFinalCostEstimate()
                                  throws StandardException

Get the final CostEstimate for this ResultSetNode.

Returns:

The final CostEstimate for this ResultSetNode.

Throws:

StandardException

assignResultSetNumber

public void assignResultSetNumber()
                           throws StandardException

Assign the next resultSetNumber to the resultSetNumber in this ResultSetNode. Expected to be done during generate().

Throws:

StandardException - Thrown on error

bindNonVTITables

public ResultSetNode bindNonVTITables(DataDictionary dataDictionary,
                                      FromList fromListParam)
                               throws StandardException

Bind the non VTI tables in this ResultSetNode. This includes getting their descriptors from the data dictionary and numbering them.

Parameters:

dataDictionary - The DataDictionary to use for binding

fromListParam - FromList to use/append to.

Returns:

ResultSetNode

Throws:

StandardException - Thrown on error

bindVTITables

public ResultSetNode bindVTITables(FromList fromListParam)
                            throws StandardException

Bind the VTI tables in this ResultSetNode. This includes getting their descriptors from the data dictionary and numbering them.

Parameters:

fromListParam - FromList to use/append to.

Returns:

ResultSetNode

Throws:

StandardException - Thrown on error

bindExpressions

public void bindExpressions(FromList fromListParam)
                     throws StandardException

Bind the expressions in this ResultSetNode. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.

Parameters:

fromListParam - FromList to use/append to.

Throws:

StandardException - Thrown on error

bindExpressionsWithTables

public void bindExpressionsWithTables(FromList fromListParam)
                               throws StandardException

Bind the expressions in this ResultSetNode if it has tables. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.

Parameters:

fromListParam - FromList to use/append to.

Throws:

StandardException - Thrown on error

bindTargetExpressions

public void bindTargetExpressions(FromList fromListParam)
                           throws StandardException

Bind the expressions in the target list. This means binding the sub-expressions, as well as figuring out what the return type is for each expression. This is useful for EXISTS subqueries, where we need to validate the target list before blowing it away and replacing it with a SELECT true.

Throws:

StandardException - Thrown on error

setTableConstructorTypes

void setTableConstructorTypes(ResultColumnList typeColumns)
                        throws StandardException

Set the type of each parameter in the result column list for this table constructor.

Parameters:

typeColumns - The ResultColumnList containing the desired result types.

Throws:

StandardException - Thrown on error

setInsertSource

public void setInsertSource()

Remember that this node is the source result set for an INSERT.

verifySelectStarSubquery

public void verifySelectStarSubquery(FromList outerFromList,
                                     int subqueryType)
                              throws StandardException

Verify that a SELECT * is valid for this type of subquery.

Parameters:

outerFromList - The FromList from the outer query block(s)

subqueryType - The subquery type

Throws:

StandardException - Thrown on error

getAllResultColumns

public ResultColumnList getAllResultColumns(TableName allTableName)
                                     throws StandardException

Expand "*" into a ResultColumnList with all of the columns in the table's result list.

Parameters:

allTableName - The qualifier on the "*"

Returns:

ResultColumnList The expanded list, or null if allTableName is non-null and doesn't match a table name in this result set

Throws:

StandardException - Thrown on error

getMatchingColumn

public ResultColumn getMatchingColumn(ColumnReference columnReference)
                               throws StandardException

Try to find a ResultColumn in the table represented by this FromTable that matches the name in the given ColumnReference.

Parameters:

columnReference - The columnReference whose name we're looking for in the given table.

Returns:

A ResultColumn whose expression is the ColumnNode that matches the ColumnReference. Returns null if there is no match.

Throws:

StandardException - Thrown on error

setResultToBooleanTrueNode

public ResultSetNode setResultToBooleanTrueNode(boolean onlyConvertAlls)
                                         throws StandardException

Set the result column for the subquery to a boolean true, Useful for transformations such as changing: where exists (select ... from ...) to: where (select true from ...) NOTE: No transformation is performed if the ResultColumn.expression is already the correct boolean constant.

Parameters:

onlyConvertAlls - Boolean, whether or not to just convert *'s

Returns:

ResultSetNode whose resultColumn was transformed; defaults to "this" here, but can be overridden by subclasses.

Throws:

StandardException - Thrown on error

getFromList

public FromList getFromList()
                     throws StandardException

Get the FromList. Create and return an empty FromList. (Subclasses which actuall have FromLists will override this.) This is useful because there is a FromList parameter to bindExpressions() which is used as the common FromList to bind against, allowing us to support correlation columns under unions in subqueries.

Returns:

FromList

Throws:

StandardException - Thrown on error

bindResultColumns

public void bindResultColumns(FromList fromListParam)
                       throws StandardException

Bind the result columns of this ResultSetNode when there is no base table to bind them to. This is useful for SELECT statements, where the result columns get their types from the expressions that live under them.

Parameters:

fromListParam - FromList to use/append to.

Throws:

StandardException - Thrown on error

bindResultColumns

public void bindResultColumns(TableDescriptor targetTableDescriptor,
                              FromVTI targetVTI,
                              ResultColumnList targetColumnList,
                              DMLStatementNode statement,
                              FromList fromListParam)
                       throws StandardException

Bind the result columns for this ResultSetNode to a base table. This is useful for INSERT and UPDATE statements, where the result columns get their types from the table being updated or inserted into. If a result column list is specified, then the verification that the result column list does not contain any duplicates will be done when binding them by name.

Parameters:

targetTableDescriptor - The TableDescriptor for the table being updated or inserted into

targetColumnList - For INSERT statements, the user does not have to supply column names (for example, "insert into t values (1,2,3)". When this parameter is null, it means that the user did not supply column names, and so the binding should be done based on order. When it is not null, it means do the binding by name, not position.

statement - Calling DMLStatementNode (Insert or Update)

fromListParam - FromList to use/append to.

Throws:

StandardException - Thrown on error

bindUntypedNullsToResultColumns

public void bindUntypedNullsToResultColumns(ResultColumnList rcl)
                                     throws StandardException

Bind untyped nulls to the types in the given ResultColumnList. This is used for binding the nulls in row constructors and table constructors. In all other cases (as of the time of this writing), we do nothing.

Parameters:

rcl - The ResultColumnList with the types to bind nulls to

Throws:

StandardException - Thrown on error

preprocess

public ResultSetNode preprocess(int numTables,
                                GroupByList gbl,
                                FromList fromList)
                         throws StandardException

Preprocess a ResultSetNode - this currently means: o Generating a referenced table map for each ResultSetNode. o Putting the WHERE and HAVING clauses in conjunctive normal form (CNF). o Converting the WHERE and HAVING clauses into PredicateLists and classifying them. o Ensuring that a ProjectRestrictNode is generated on top of every FromBaseTable and generated in place of every FromSubquery. o Pushing single table predicates down to the new ProjectRestrictNodes.

Parameters:

numTables - The number of tables in the DML Statement

gbl - The group by list, if any

fromList - The from list, if any

Returns:

ResultSetNode at top of preprocessed tree.

Throws:

StandardException - Thrown on error

projectResultColumns

void projectResultColumns()
                    throws StandardException

Find the unreferenced result columns and project them out.

Throws:

StandardException

ensurePredicateList

public ResultSetNode ensurePredicateList(int numTables)
                                  throws StandardException

Ensure that the top of the RSN tree has a PredicateList.

Parameters:

numTables - The number of tables in the query.

Returns:

ResultSetNode A RSN tree with a node which has a PredicateList on top.

Throws:

StandardException - Thrown on error

addNewPredicate

public ResultSetNode addNewPredicate(Predicate predicate)
                              throws StandardException

Add a new predicate to the list. This is useful when doing subquery transformations, when we build a new predicate with the left side of the subquery operator and the subquery's result column.

Parameters:

predicate - The predicate to add

Returns:

ResultSetNode The new top of the tree.

Throws:

StandardException - Thrown on error

flattenableInFromSubquery

public boolean flattenableInFromSubquery(FromList fromList)

Evaluate whether or not the subquery in a FromSubquery is flattenable. Currently, a FSqry is flattenable if all of the following are true: o Subquery is a SelectNode. (ie, not a RowResultSetNode or a UnionNode) o It contains no top level subqueries. (RESOLVE - we can relax this) o It does not contain a group by or having clause o It does not contain aggregates.

Parameters:

fromList - The outer from list

Returns:

boolean Whether or not the FromSubquery is flattenable.

genProjectRestrictForReordering

ResultSetNode genProjectRestrictForReordering()
                                        throws StandardException

Get a parent ProjectRestrictNode above us. This is useful when we need to preserve the user specified column order when reordering the columns in the distinct when we combine an order by with a distinct.

Returns:

A parent ProjectRestrictNode to do column reordering

Throws:

StandardException - Thrown on error

optimize

public ResultSetNode optimize(DataDictionary dataDictionary,
                              PredicateList predicates,
                              double outerRows)
                       throws StandardException

Optimize a ResultSetNode. This means choosing the best access path for each table under the ResultSetNode, among other things. The only RSNs that need to implement their own optimize() are a SelectNode and those RSNs that can appear above a SelectNode in the query tree. Currently, a ProjectRestrictNode is the only RSN that can appear above a SelectNode.

Parameters:

dataDictionary - The DataDictionary to use for optimization

predicates - The PredicateList to apply.

outerRows - The number of outer joining rows

Returns:

ResultSetNode The top of the optimized query tree

Throws:

StandardException - Thrown on error

modifyAccessPaths

public ResultSetNode modifyAccessPaths()
                                throws StandardException

Modify the access paths according to the decisions the optimizer made. This can include adding project/restrict nodes, index-to-base-row nodes, etc.

Returns:

The modified query tree

Throws:

StandardException - Thrown on error

modifyAccessPaths

public ResultSetNode modifyAccessPaths(PredicateList predList)
                                throws StandardException

Modify the access paths according to the decisions the optimizer made. This can include adding project/restrict nodes, index-to-base-row nodes, etc.

Parameters:

predList - A list of optimizable predicates that should be pushed to this ResultSetNode, as determined by optimizer.

Returns:

The modified query tree

Throws:

StandardException - Thrown on error

makeResultDescriptors

ResultColumnDescriptor[] makeResultDescriptors()

columnTypesAndLengthsMatch

boolean columnTypesAndLengthsMatch()
                             throws StandardException

Throws:

StandardException

setResultColumns

public void setResultColumns(ResultColumnList newRCL)

Set the resultColumns in this ResultSetNode

Parameters:

newRCL - The new ResultColumnList for this ResultSetNode

getResultColumns

public ResultColumnList getResultColumns()

Get the resultColumns for this ResultSetNode

Returns:

ResultColumnList for this ResultSetNode

setReferencedTableMap

public void setReferencedTableMap(JBitSet newRTM)

Set the referencedTableMap in this ResultSetNode

Parameters:

newRTM - The new referencedTableMap for this ResultSetNode

getReferencedTableMap

public JBitSet getReferencedTableMap()

Get the referencedTableMap for this ResultSetNode

Returns:

JBitSet Referenced table map for this ResultSetNode

fillInReferencedTableMap

public void fillInReferencedTableMap(JBitSet passedMap)

Fill the referencedTableMap with this ResultSetNode.

Parameters:

passedMap - The table map to fill in.

rejectParameters

public void rejectParameters()
                      throws StandardException

Check for (and reject) ? parameters directly under the ResultColumns. This is done for SELECT statements.

Throws:

StandardException - Thrown if a ? parameter found directly under a ResultColumn

rejectXMLValues

public void rejectXMLValues()
                     throws StandardException

Check for (and reject) XML values directly under the ResultColumns. This is done for SELECT/VALUES statements. We reject values in this case because JDBC does not define an XML type/binding and thus there's no standard way to pass such a type back to a JDBC application.

Throws:

StandardException - Thrown if an XML value found directly under a ResultColumn

renameGeneratedResultNames

public void renameGeneratedResultNames()
                                throws StandardException

Rename generated result column names as '1', '2' etc... These will be the result column names seen by JDBC clients.

Throws:

StandardException

markStatementResultSet

public void markStatementResultSet()

This method is overridden to allow a resultset node to know if it is the one controlling the statement -- i.e., it is the outermost result set node for the statement.

enhanceRCLForInsert

ResultSetNode enhanceRCLForInsert(InsertNode target,
                                  boolean inOrder,
                                  int[] colMap)
                            throws StandardException

This ResultSet is the source for an Insert. The target RCL is in a different order and/or a superset of this RCL. In most cases we will add a ProjectRestrictNode on top of the source with an RCL that matches the target RCL. NOTE - The new or enhanced RCL will be fully bound.

Parameters:

target - the target node for the insert

inOrder - are source cols in same order as target cols?

colMap - int array representation of correspondence between RCLs - colmap[i] = -1 -> missing in current RCL colmap[i] = j -> targetRCL(i) <-> thisRCL(j+1)

Returns:

a node that replaces this node and whose RCL matches the target RCL. May return this node if no changes to the RCL are needed, or if the RCL is modified in-place.

Throws:

StandardException - Thrown on error

getRCLForInsert

ResultColumnList getRCLForInsert(InsertNode target,
                                 int[] colMap)
                           throws StandardException

Generate an RCL that can replace the original RCL of this node to match the RCL of the target for the insert.

Parameters:

target - the target node for the insert

colMap - int array representation of correspondence between RCLs - colmap[i] = -1 -> missing in current RCL colmap[i] = j -> targetRCL(i) <-> thisRCL(j+1)

Returns:

an RCL that matches the target RCL

Throws:

StandardException

genNewRCForInsert

private ResultColumn genNewRCForInsert(TableDescriptor targetTD,
                                       FromVTI targetVTI,
                                       int columnNumber,
                                       DataDictionary dataDictionary)
                                throws StandardException

Generate the RC/expression for an unspecified column in an insert. Use the default if one exists.

Parameters:

targetTD - Target TableDescriptor if the target is not a VTI, null if a VTI.

targetVTI - Target description if it is a VTI, null if not a VTI

columnNumber - The column number

dataDictionary - The DataDictionary

Returns:

The RC/expression for the unspecified column.

Throws:

StandardException - Thrown on error

generateProjectRestrictForInsert

private ResultSetNode generateProjectRestrictForInsert(InsertNode target,
                                                       int[] colMap)
                                                throws StandardException

Generate a ProjectRestrictNode to put on top of this node if it's the source for an insert, and the RCL needs reordering and/or addition of columns in order to match the target RCL.

Parameters:

target - the target node for the insert

colMap - int array representation of correspondence between RCLs - colmap[i] = -1 -> missing in current RCL colmap[i] = j -> targetRCL(i) <-> thisRCL(j+1)

Returns:

a ProjectRestrictNode whos RCL matches the target RCL

Throws:

StandardException

createGeneratedColumn

private ResultColumn createGeneratedColumn(TableDescriptor targetTD,
                                           ColumnDescriptor colDesc)
                                    throws StandardException

Create a ResultColumn for a column with a generation clause.

Throws:

StandardException

parseDefault

public ValueNode parseDefault(java.lang.String defaultText)
                       throws StandardException

Parse a default and turn it into a query tree.

Parameters:

defaultText - Text of Default.

Returns:

The parsed default as a query tree.

Throws:

StandardException - Thrown on failure

makeResultDescription

public ResultDescription makeResultDescription()

Make a ResultDescription for use in a ResultSet. This is useful when generating/executing a NormalizeResultSet, since it can appear anywhere in the tree.

Returns:

A ResultDescription for this ResultSetNode.

isUpdatableCursor

boolean isUpdatableCursor(DataDictionary dd)
                    throws StandardException

Determine if this result set is updatable or not, for a cursor (i.e., is it a cursor-updatable select). This returns false and we expect selectnode to refine it for further checking.

Throws:

StandardException - Thrown on error

getCursorTargetTable

FromTable getCursorTargetTable()

return the target table of an updatable cursor result set. since this is not updatable, just return null.

markAsCursorTargetTable

public boolean markAsCursorTargetTable()

Mark this ResultSetNode as the target table of an updatable cursor. Most types of ResultSetNode can't be target tables.

Returns:

true if the target table supports positioned updates.

notCursorTargetTable

void notCursorTargetTable()

Mark this ResultSetNode as *not* the target table of an updatable cursor.

genProjectRestrict

public ResultSetNode genProjectRestrict()
                                 throws StandardException

Put a ProjectRestrictNode on top of this ResultSetNode. ColumnReferences must continue to point to the same ResultColumn, so that ResultColumn must percolate up to the new PRN. However, that ResultColumn will point to a new expression, a VirtualColumnNode, which points to the FromTable and the ResultColumn that is the source for the ColumnReference. (The new PRN will have the original of the ResultColumnList and the ResultColumns from that list. The FromTable will get shallow copies of the ResultColumnList and its ResultColumns. ResultColumn.expression will remain at the FromTable, with the PRN getting a new VirtualColumnNode for each ResultColumn.expression.) This is useful for UNIONs, where we want to generate a DistinctNode above the UnionNode to eliminate the duplicates, because DistinctNodes expect their immediate child to be a PRN.

Returns:

The generated ProjectRestrictNode atop the original ResultSetNode.

Throws:

StandardException - Thrown on error

genProjectRestrict

protected ResultSetNode genProjectRestrict(int numTables)
                                    throws StandardException

Put a ProjectRestrictNode on top of each FromTable in the FromList. ColumnReferences must continue to point to the same ResultColumn, so that ResultColumn must percolate up to the new PRN. However, that ResultColumn will point to a new expression, a VirtualColumnNode, which points to the FromTable and the ResultColumn that is the source for the ColumnReference. (The new PRN will have the original of the ResultColumnList and the ResultColumns from that list. The FromTable will get shallow copies of the ResultColumnList and its ResultColumns. ResultColumn.expression will remain at the FromTable, with the PRN getting a new VirtualColumnNode for each ResultColumn.expression.) We then project out the non-referenced columns. If there are no referenced columns, then the PRN's ResultColumnList will consist of a single ResultColumn whose expression is 1.

Parameters:

numTables - Number of tables in the DML Statement

Returns:

The generated ProjectRestrictNode atop the original FromTable.

Throws:

StandardException - Thrown on error

generateNormalizationResultSet

public void generateNormalizationResultSet(ActivationClassBuilder acb,
                                           MethodBuilder mb,
                                           int resultSetNumber,
                                           ResultDescription resultDescription)
                                    throws StandardException

Generate the code for a NormalizeResultSet. The call must push two items before calling this method

1. pushGetResultSetFactoryExpression
2. the expression to normalize

Parameters:

acb - The ActivationClassBuilder

mb - The method to put the generated code in

resultSetNumber - The result set number for the NRS

resultDescription - The ERD for the ResultSet

Throws:

StandardException - Thrown on error

changeAccessPath

public ResultSetNode changeAccessPath()
                               throws StandardException

The optimizer's decision on the access path for a result set may require the generation of extra result sets. For example, if it chooses an index for a FromBaseTable, we need an IndexToBaseRowNode above the FromBaseTable (and the FromBaseTable has to change its column list to match the index. This method in the parent class does not generate any extra result sets. It may be overridden in child classes.

Returns:

A ResultSetNode tree modified to do any extra processing for the chosen access path

Throws:

StandardException - Thrown on error

referencesTarget

public boolean referencesTarget(java.lang.String name,
                                boolean baseTable)
                         throws StandardException

Search to see if a query references the specifed table name.

Parameters:

name - Table name (String) to search for.

baseTable - Whether or not name is for a base table

Returns:

true if found, else false

Throws:

StandardException - Thrown on error

subqueryReferencesTarget

boolean subqueryReferencesTarget(java.lang.String name,
                                 boolean baseTable)
                           throws StandardException

Return whether or not this ResultSetNode contains a subquery with a reference to the specified target.

Parameters:

name - The table name.

Returns:

boolean Whether or not a reference to the table was found.

Throws:

StandardException - Thrown on error

isOneRowResultSet

public boolean isOneRowResultSet()
                          throws StandardException

Return whether or not the underlying ResultSet tree will return a single row, at most. This is important for join nodes where we can save the extra next on the right side if we know that it will return at most 1 row.

Returns:

Whether or not the underlying ResultSet tree will return a single row.

Throws:

StandardException - Thrown on error

isNotExists

public boolean isNotExists()

Return whether or not the underlying ResultSet tree is for a NOT EXISTS join.

Returns:

Whether or not the underlying ResultSet tree if for NOT EXISTS.

getOptimizer

protected Optimizer getOptimizer(OptimizableList optList,
                                 OptimizablePredicateList predList,
                                 DataDictionary dataDictionary,
                                 RequiredRowOrdering requiredRowOrdering)
                          throws StandardException

Get an optimizer to use for this ResultSetNode. Only get it once - subsequent calls return the same optimizer.

Throws:

StandardException - Thrown on error

getOptimizerImpl

protected OptimizerImpl getOptimizerImpl()

Get the optimizer for this result set.

Returns:

If this.optimizer has has already been created by the getOptimizer() method above, then return it; otherwise, return null.

getNewCostEstimate

protected CostEstimate getNewCostEstimate()
                                   throws StandardException

Get a cost estimate to use for this ResultSetNode.

Throws:

StandardException - Thrown on error

acceptChildren

void acceptChildren(Visitor v)
              throws StandardException

Accept the visitor for all visitable children of this node.

Overrides:

acceptChildren in class QueryTreeNode

Parameters:

v - the visitor

Throws:

StandardException - on error

considerMaterialization

public ResultSetNode considerMaterialization(JBitSet outerTables)
                                      throws StandardException

Consider materialization for this ResultSet tree if it is valid and cost effective (It is not valid if incorrect results would be returned.)

Returns:

Top of the new/same ResultSet tree.

Throws:

StandardException - Thrown on error

performMaterialization

public boolean performMaterialization(JBitSet outerTables)
                               throws StandardException

Return whether or not to materialize this ResultSet tree.

Returns:

Whether or not to materialize this ResultSet tree. would return valid results.

Throws:

StandardException - Thrown on error

getFromTableByName

protected FromTable getFromTableByName(java.lang.String name,
                                       java.lang.String schemaName,
                                       boolean exactMatch)
                                throws StandardException

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

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

decrementLevel

abstract void decrementLevel(int decrement)

Decrement (query block) level (0-based) for all of the tables in this ResultSet tree. This is useful when flattening a subquery.

Parameters:

decrement - The amount to decrement by.

pushOrderByList

void pushOrderByList(OrderByList orderByList)

Push the order by list down from the cursor node into its child result set so that the optimizer has all of the information that it needs to consider sort avoidance.

Parameters:

orderByList - The order by list

pushOffsetFetchFirst

void pushOffsetFetchFirst(ValueNode offset,
                          ValueNode fetchFirst,
                          boolean hasJDBClimitClause)

Push down the offset and fetch first parameters, if any. This method should be overridden by the result sets that need this.

Parameters:

offset - the OFFSET, if any

fetchFirst - the OFFSET FIRST, if any

hasJDBClimitClause - true if the clauses were added by (and have the semantics of) a JDBC limit clause

generateResultSet

public void generateResultSet(ExpressionClassBuilder acb,
                              MethodBuilder mb)
                       throws StandardException

General logic shared by Core compilation and by the Replication Filter compiler. A couple ResultSets (the ones used by PREPARE SELECT FILTER) implement this method.

Parameters:

acb - The ExpressionClassBuilder for the class being built

mb - The method the expression will go into

Throws:

StandardException - Thrown on error

updateTargetLockMode

public int updateTargetLockMode()

Get the lock mode for the target of an update statement (a delete or update). The update mode will always be row for CurrentOfNodes. It will be table if there is no where clause.

Returns:

The lock mode

See Also:

TransactionController

notFlattenableJoin

void notFlattenableJoin()

Mark this node and its children as not being a flattenable join.

isOrderedOn

boolean isOrderedOn(ColumnReference[] crs,
                    boolean permuteOrdering,
                    java.util.List fbtVector)
              throws StandardException

Return whether or not the underlying ResultSet tree is ordered on the specified columns. RESOLVE - This method currently only considers the outermost table of the query block.

Parameters:

crs - The specified ColumnReference[]

permuteOrdering - Whether or not the order of the CRs in the array can be permuted

fbtVector - Vector that is to be filled with the FromBaseTable

Returns:

Whether the underlying ResultSet tree is ordered on the specified column.

Throws:

StandardException - Thrown on error

returnsAtMostOneRow

boolean returnsAtMostOneRow()

Return whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics. (A RowResultSetNode and a SELECT with a non-grouped aggregate will return at most 1 row.)

Returns:

Whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics.

replaceOrForbidDefaults

void replaceOrForbidDefaults(TableDescriptor ttd,
                             ResultColumnList tcl,
                             boolean allowDefaults)
                       throws StandardException

Replace any DEFAULTs with the associated tree for the default if allowed, or flag (when inside top level set operator nodes). Subqueries are checked for illegal DEFAULTs elsewhere.

Parameters:

ttd - The TableDescriptor for the target table.

tcl - The RCL for the target table.

allowDefaults - true if allowed

Throws:

StandardException - Thrown on error

isPossibleDistinctScan

boolean isPossibleDistinctScan(java.util.Set distinctColumns)

Is it possible to do a distinct scan on this ResultSet tree. (See SelectNode for the criteria.)

Parameters:

distinctColumns - the set of distinct columns

Returns:

Whether or not it is possible to do a distinct scan on this ResultSet tree.

markForDistinctScan

void markForDistinctScan()

Mark the underlying scan as a distinct scan.

adjustForSortElimination

void adjustForSortElimination()

Notify the underlying result set tree that the optimizer has chosen to "eliminate" a sort. Sort elimination can happen as part of preprocessing (see esp. SelectNode.preprocess(...)) or it can happen if the optimizer chooses an access path that inherently returns the rows in the correct order (also known as a "sort avoidance" plan). In either case we drop the sort and rely on the underlying result set tree to return its rows in the correct order. For most types of ResultSetNodes we automatically get the rows in the correct order if the sort was eliminated. One exception to this rule, though, is the case of an IndexRowToBaseRowNode, for which we have to disable bulk fetching on the underlying base table. Otherwise the index scan could return rows out of order if the base table is updated while the scan is "in progress" (i.e. while the result set is open). In order to account for this (and potentially other, similar issues in the future) this method exists to notify the result set node that it is expected to return rows in the correct order. The result set can then take necessary action to satsify this requirement--such as disabling bulk fetch in the case of IndexRowToBaseRowNode. All of that said, any ResultSetNodes for which we could potentially eliminate sorts should override this method accordingly. So we don't ever expect to get here.

adjustForSortElimination

void adjustForSortElimination(RequiredRowOrdering rowOrdering)
                        throws StandardException

Same goal as adjustForSortElimination above, but this version takes a RequiredRowOrdering to allow nodes to adjust based on the ORDER BY clause, if needed.

Throws:

StandardException

numDistinctAggregates

protected static final int numDistinctAggregates(java.util.List aggregateVector)

Count the number of distinct aggregates in the list. By 'distinct' we mean aggregates of the form:

SELECT MAX(DISTINCT x) FROM T<\I><\UL>

Returns:

number of aggregates

LOJgetReferencedTables

public JBitSet LOJgetReferencedTables(int numTables)
                               throws StandardException

Throws:

StandardException