Module org.apache.derby.engine
Package org.apache.derby.vti

Interface VTIEnvironment

  • public interface VTIEnvironment

    VTIEnvironment is the state variable created by the optimizer to help it place a Table Function in the join order. The methods of VTICosting use this state variable in order to pass information to each other and learn other details of the operating environment.

    See Also:
    VTICosting

    • Method Detail

      • isCompileTime

        boolean isCompileTime()
        Return true if this instance of the Table Function has been created for compilation, false if it is for runtime execution.
        Returns:
        true if this instance of the Table Function has been created for compilation

      • getOriginalSQL

        String getOriginalSQL()
        Return the SQL text of the original SQL statement.
        Returns:
        the SQL text of the original SQL statement

      • getStatementIsolationLevel

        int getStatementIsolationLevel()
        Get the specific JDBC isolation of the statement. If it returns Connection.TRANSACTION_NONE then no isolation was specified and the connection's isolation level is implied.
        Returns:
        the specific JDBC isolation of the statement

      • setSharedState

        void setSharedState​(String key,
                    Serializable value)
        Saves an object associated with a key that will be maintained for the lifetime of the statement plan. Any previous value associated with the key is discarded. Any saved object can be seen by any JDBC Connection that has a Statement object that references the same statement plan.
        Parameters:
        key - Key into a cache of context variables
        value - Value to associate with the key

      • getSharedState

        Object getSharedState​(String key)
        Get an object associated with a key from set of objects maintained with the statement plan.
        Parameters:
        key - Key into a cache of context variables
        Returns:
        the value associated with the key