Class RowResultSetNode

java.lang.Object
org.apache.derby.impl.sql.compile.QueryTreeNode
org.apache.derby.impl.sql.compile.ResultSetNode
org.apache.derby.impl.sql.compile.FromTable
org.apache.derby.impl.sql.compile.RowResultSetNode
All Implemented Interfaces:
Optimizable, Visitable
class RowResultSetNode extends FromTable
A RowResultSetNode represents the result set for a VALUES clause.

  • Field Details

  • Constructor Details

    • RowResultSetNode

      RowResultSetNode(ResultColumnList valuesClause, Properties tableProperties, ContextManager cm)
      Constructor for a RowResultSetNode.
      Parameters:
      valuesClause - The result column list for the VALUES clause.
      tableProperties - Properties list associated with the table
      cm - The context manager

  • Method Details

    • statementToString

      String statementToString()

    • printSubNodes

      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 ResultSetNode
      Parameters:
      depth - The depth of this node in the tree

    • referencesSessionSchema

      public boolean referencesSessionSchema() throws StandardException
      Description copied from class: QueryTreeNode
      Return true if the node references SESSION schema tables (temporary or permanent)
      Overrides:
      referencesSessionSchema in class QueryTreeNode
      Returns:
      true if references SESSION schema tables, else false
      Throws:
      StandardException - Thrown on error

    • enhanceRCLForInsert

      ResultSetNode enhanceRCLForInsert(InsertNode target, boolean inOrder, int[] colMap) throws StandardException
      Modify the RCL of this node to match the target of the insert.
      Overrides:
      enhanceRCLForInsert in class ResultSetNode
      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

    • estimateCost

      public CostEstimate estimateCost(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering) throws StandardException
      Description copied from interface: Optimizable
      Estimate the cost of scanning this Optimizable using the given predicate list with the given conglomerate. It is assumed that the predicate list has already been classified. This cost estimate is just for one scan, not for the life of the query.
      Specified by:
      estimateCost in interface Optimizable
      Overrides:
      estimateCost in class FromTable
      Parameters:
      predList - The predicate list to optimize against
      cd - The conglomerate descriptor to get the cost of
      outerCost - The estimated cost of the part of the plan outer to this optimizable.
      optimizer - The optimizer to use to help estimate the cost
      rowOrdering - The row ordering for all the tables in the join order, including this one.
      Returns:
      The estimated cost of doing the scan
      Throws:
      StandardException - Thrown on error
      See Also:

    • bindNonVTITables

      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.
      Overrides:
      bindNonVTITables in class ResultSetNode
      Parameters:
      dataDictionary - The DataDictionary to use for binding
      fromListParam - FromList to use/append to.
      Returns:
      ResultSetNode
      Throws:
      StandardException - Thrown on error

    • bindExpressions

      void bindExpressions(FromList fromListParam) throws StandardException
      Bind the expressions in this RowResultSetNode. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.
      Overrides:
      bindExpressions in class ResultSetNode
      Parameters:
      fromListParam - FromList to use/append to.
      Throws:
      StandardException - Thrown on error

    • bindExpressionsWithTables

      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.
      Overrides:
      bindExpressionsWithTables in class ResultSetNode
      Parameters:
      fromListParam - FromList to use/append to.
      Throws:
      StandardException - Thrown on error

    • bindTargetExpressions

      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.
      Overrides:
      bindTargetExpressions in class ResultSetNode
      Throws:
      StandardException - Thrown on error

    • bindUntypedNullsToResultColumns

      void bindUntypedNullsToResultColumns(ResultColumnList bindingRCL) throws StandardException
      Bind any untyped null nodes to the types in the given ResultColumnList.
      Overrides:
      bindUntypedNullsToResultColumns in class ResultSetNode
      Parameters:
      bindingRCL - The ResultColumnList with the types to bind to.
      Throws:
      StandardException - Thrown on error

    • getMatchingColumn

      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.
      Overrides:
      getMatchingColumn in class ResultSetNode
      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

    • getExposedName

      String getExposedName() throws StandardException
      Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.
      Overrides:
      getExposedName in class FromTable
      Returns:
      The exposed name of this table.
      Throws:
      StandardException - Thrown on error

    • verifySelectStarSubquery

      void verifySelectStarSubquery(FromList outerFromList, int subqueryType) throws StandardException
      Verify that a SELECT * is valid for this type of subquery.
      Overrides:
      verifySelectStarSubquery in class ResultSetNode
      Parameters:
      outerFromList - The FromList from the outer query block(s)
      subqueryType - The subquery type
      Throws:
      StandardException - Thrown on error

    • pushQueryExpressionSuffix

      public void pushQueryExpressionSuffix()
      Description copied from class: ResultSetNode
      Set up a new level for order by and fetch/offset clauses. See Javadoc for ResultSetNode.QueryExpressionClauses. Overridden by implementors of pushOrderByNode, pushOffsetFetchFirst.
      Overrides:
      pushQueryExpressionSuffix in class ResultSetNode

    • 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.
      Overrides:
      pushOrderByList in class ResultSetNode
      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, to this node.
      Overrides:
      pushOffsetFetchFirst in class ResultSetNode
      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

    • preprocess

      ResultSetNode preprocess(int numTables, GroupByList gbl, FromList fromList) 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.
      Overrides:
      preprocess in class ResultSetNode
      Parameters:
      numTables - Number of tables in the DML Statement
      gbl - The group by list, if any
      fromList - The from list, if any
      Returns:
      The generated ProjectRestrictNode atop the original FromTable.
      Throws:
      StandardException - Thrown on error

    • ensurePredicateList

      ResultSetNode ensurePredicateList(int numTables) throws StandardException
      Ensure that the top of the RSN tree has a PredicateList.
      Overrides:
      ensurePredicateList in class ResultSetNode
      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

      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.
      Overrides:
      addNewPredicate in class ResultSetNode
      Parameters:
      predicate - The predicate to add
      Returns:
      ResultSetNode The new top of the tree.
      Throws:
      StandardException - Thrown on error

    • flattenableInFromSubquery

      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 or a RowResultSetNode (not 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. o There is at least one result set in the from list that is not a RowResultSetNode (the reason is to avoid having an outer SelectNode with an empty FromList.
      Overrides:
      flattenableInFromSubquery in class ResultSetNode
      Parameters:
      fromList - The outer from list
      Returns:
      boolean Whether or not the FromSubquery is flattenable.

    • optimize

      ResultSetNode optimize(DataDictionary dataDictionary, PredicateList predicateList, double outerRows) throws StandardException
      Optimize this SelectNode. This means choosing the best access path for each table, among other things.
      Overrides:
      optimize in class ResultSetNode
      Parameters:
      dataDictionary - The DataDictionary to use for optimization
      predicateList - The predicate list to optimize against
      outerRows - The number of outer joining rows
      Returns:
      ResultSetNode The top of the optimized tree
      Throws:
      StandardException - Thrown on error

    • modifyAccessPath

      public Optimizable modifyAccessPath(JBitSet outerTables) throws StandardException
      Description copied from interface: Optimizable
      Modify the access path for this Optimizable, as necessary. This includes things like adding a result set to translate from index rows to base rows
      Specified by:
      modifyAccessPath in interface Optimizable
      Overrides:
      modifyAccessPath in class FromTable
      Parameters:
      outerTables - Bit map of the tables that are outer to this one in the join order.
      Returns:
      The (potentially new) Optimizable at the top of the tree.
      Throws:
      StandardException - Thrown on error
      See Also:

    • modifyAccessPaths

      ResultSetNode modifyAccessPaths() throws StandardException
      Description copied from class: ResultSetNode
      Modify the access paths according to the decisions the optimizer made. This can include adding project/restrict nodes, index-to-base-row nodes, etc.
      Overrides:
      modifyAccessPaths in class ResultSetNode
      Returns:
      The modified query tree
      Throws:
      StandardException - Thrown on error
      See Also:

    • 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.)
      Overrides:
      returnsAtMostOneRow in class ResultSetNode
      Returns:
      Whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics.

    • setTableConstructorTypes

      void setTableConstructorTypes(ResultColumnList typeColumns) throws StandardException
      Set the type of each parameter in the result column list for this table constructor.
      Overrides:
      setTableConstructorTypes in class ResultSetNode
      Parameters:
      typeColumns - The ResultColumnList containing the desired result types.
      Throws:
      StandardException - Thrown on error

    • generate

      void generate(ActivationClassBuilder acb, MethodBuilder mb) throws StandardException
      The generated ResultSet will be: RowResultSet -- for the VALUES clause
      Overrides:
      generate in class QueryTreeNode
      Parameters:
      acb - The ActivationClassBuilder for the class being built
      mb - The method for the generated code to go into
      Throws:
      StandardException - Thrown on error

    • 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.
      Overrides:
      replaceOrForbidDefaults in class ResultSetNode
      Parameters:
      ttd - The TableDescriptor for the target table.
      tcl - The RCL for the target table.
      allowDefaults - true if allowed
      Throws:
      StandardException - Thrown on error

    • optimizeSubqueries

      void optimizeSubqueries(DataDictionary dd, double rowCount) throws StandardException
      Optimize any subqueries that haven't been optimized any where else. This is useful for a RowResultSetNode as a derived table because it doesn't get optimized otherwise.
      Overrides:
      optimizeSubqueries in class FromTable
      Throws:
      StandardException - Thrown on error

    • adjustForSortElimination

      void adjustForSortElimination()
      Description copied from class: ResultSetNode
      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.
      Overrides:
      adjustForSortElimination in class ResultSetNode
      See Also:

    • canWeCacheResults

      private boolean canWeCacheResults() throws StandardException
      Throws:
      StandardException