Class SqlExplain

All Implemented Interfaces:

public class SqlExplain extends SqlCall
A SqlExplain is a node of a parse tree which represents an EXPLAIN PLAN statement.
  • Field Details

  • Constructor Details

  • Method Details

    • getKind

      public SqlKind getKind()
      Description copied from class: SqlNode
      Returns the type of node this is, or SqlKind.OTHER if it's nothing special.
      getKind in class SqlCall
      a SqlKind value, never null
      See Also:
    • getOperator

      public SqlOperator getOperator()
      Specified by:
      getOperator in class SqlCall
    • getOperandList

      public List<SqlNode> getOperandList()
      Description copied from class: SqlCall
      Returns the list of operands. The set and order of operands is call-specific.

      Note: the proper type would be List<@Nullable SqlNode>, however, it would trigger too many changes to the current codebase.

      Specified by:
      getOperandList in class SqlCall
      the list of call operands, never null, the operands can be null
    • setOperand

      public void setOperand(int i, @Nullable SqlNode operand)
      Description copied from class: SqlCall
      Changes the value of an operand. Allows some rewrite by SqlValidator; use sparingly.
      setOperand in class SqlCall
      i - Operand index
      operand - Operand value
    • getExplicandum

      @Pure public SqlNode getExplicandum()
      Returns the underlying SQL statement to be explained.
    • getDetailLevel

      @Pure public SqlExplainLevel getDetailLevel()
      Return the detail level to be generated.
    • getDepth

      @Pure public SqlExplain.Depth getDepth()
      Returns the level of abstraction at which this plan should be displayed.
    • getDynamicParamCount

      @Pure public int getDynamicParamCount()
      Returns the number of dynamic parameters in the statement.
    • withImplementation

      @Pure public boolean withImplementation()
      Returns whether physical plan implementation should be returned.
    • withType

      @Pure public boolean withType()
      Returns whether type should be returned.
    • getFormat

      @Pure public SqlExplainFormat getFormat()
      Returns the desired output format.
    • isXml

      @Deprecated public boolean isXml()
      Returns whether result is to be in XML format.
    • isJson

      public boolean isJson()
      Returns whether result is to be in JSON format.
    • unparse

      public void unparse(SqlWriter writer, int leftPrec, int rightPrec)
      Description copied from class: SqlNode
      Writes a SQL representation of this node to a writer.

      The leftPrec and rightPrec parameters give us enough context to decide whether we need to enclose the expression in parentheses. For example, we need parentheses around "2 + 3" if preceded by "5 *". This is because the precedence of the "*" operator is greater than the precedence of the "+" operator.

      The algorithm handles left- and right-associative operators by giving them slightly different left- and right-precedence.

      If SqlWriter.isAlwaysUseParentheses() is true, we use parentheses even when they are not required by the precedence rules.

      For the details of this algorithm, see SqlCall.unparse(org.apache.calcite.sql.SqlWriter, int, int).

      unparse in class SqlCall
      writer - Target writer
      leftPrec - The precedence of the SqlNode immediately preceding this node in a depth-first scan of the parse tree
      rightPrec - The precedence of the SqlNode immediately