DSIExtPassdownInformation Class Reference

Provides information about which passdown operations are supported. More...

List of all members.

Public Member Functions

virtual bool CanHandlePassdown (AERelationalExpr *in_node)
 Checks if the given JOIN expression can be successfully passed down.
virtual bool CanHandlePassdown (AEBooleanExpr *in_node)
 Checks if the given Boolean expression can be successfully passed down.
 DSIExtPassdownInformation ()
 Default constructor.
virtual ~DSIExtPassdownInformation ()
 Destructor.

Detailed Description

Provides information about which passdown operations are supported.

This class has default implementations for all functions. The DSII should override the default implementations.


Constructor & Destructor Documentation

Default constructor.

virtual ~DSIExtPassdownInformation (  )  [virtual]

Destructor.


Member Function Documentation

virtual bool CanHandlePassdown ( AERelationalExpr in_node  )  [virtual]

Checks if the given JOIN expression can be successfully passed down.

A successful passdown means that the DSII can execute the given JOIN expression. If it cannot execute the Boolean expression, it must return false.

This default implementation always returns 'true'. CanHandlePassdown() is called internally and is used to determine whether or not certain pushdown filter optimizations are done. The rationale is that a filter that the DSII cannot handle should not be pushed down below a JOIN if the DSII could otherwise handle passdown of the join.

Parameters:
in_node The JOIN expression to check. (NOT OWN)
Returns:
True if the given JOIN expression can be successfully passed down, false otherwise.
virtual bool CanHandlePassdown ( AEBooleanExpr in_node  )  [virtual]

Checks if the given Boolean expression can be successfully passed down.

A successful passdown means that the DSII can execute the given Boolean expression. If it cannot execute the Boolean expression, it must return false.

This default implementation always returns 'true'. CanHandlePassdown() is called internally and is used to determine whether or not certain pushdown filter optimizations are done. The rationale is that a filter that the DSII cannot handle should not be pushed down below a JOIN if the DSII could otherwise handle passdown of the join.

Parameters:
in_node The boolean expression to check. (NOT OWN)
Returns:
True if the given Boolean expression can be successfully passed down, false otherwise.

The documentation for this class was generated from the following file:

Generated on Wed May 17 14:21:17 2017 for SimbaEngine 10.1.3.1011 by simba