com.bigdata.bop.cost

Class IndexSegmentCostModel

java.lang.Object

com.bigdata.bop.cost.IndexSegmentCostModel

All Implemented Interfaces:

Serializable

public class IndexSegmentCostModel
extends Object
implements Serializable

A cost model for a range scan on an IndexSegment.

Note: This uses a summary description of the IndexSegment for the cost model. This makes sense because we generally have 100s of index segments in scale-out and we do not want to probe them all for their exact costs.

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
IndexSegmentCostModel(DiskCostModel diskCostModel)

Method Summary

Methods

Modifier and Type	Method and Description
double	rangeScan(int rangeCount, int branchingFactor, int averageBytesPerLeaf, int xferBufferSize)

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexSegmentCostModel

public IndexSegmentCostModel(DiskCostModel diskCostModel)

Parameters:

diskCostModel - The disk cost model.

Method Detail

rangeScan

public double rangeScan(int rangeCount,
               int branchingFactor,
               int averageBytesPerLeaf,
               int xferBufferSize)

Parameters:

rangeCount - The range count for the index scan.

branchingFactor - The branching factor for the index segments for this scale-out index.

averageBytesPerLeaf - The average #of bytes per leaf for this scale-out index.

xferBufferSize - The size of the disk transfer buffer.

Returns:

The estimated time for the range scan (milliseconds).