org.apache.hawq.pxf.service.utilities

Class AnalyzeUtils

java.lang.Object

org.apache.hawq.pxf.service.utilities.AnalyzeUtils

public class AnalyzeUtils
extends java.lang.Object

Helper class to get statistics for ANALYZE.

Constructor Summary

Constructors

Constructor and Description
AnalyzeUtils()

Method Summary

Modifier and Type	Method and Description
static java.util.BitSet	generateSamplingBitSet(int poolSize, int sampleSize) Marks sampleSize bits out of the poolSize, in a uniform way.
static java.util.List<Fragment>	getSampleFragments(java.util.List<Fragment> fragments, ProtocolData protData) In case pxf_max_fragments parameter is declared, make sure not to get over the limit.

Methods inherited from class java.lang.Object

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

Constructor Detail

AnalyzeUtils

public AnalyzeUtils()

Method Detail

getSampleFragments

public static java.util.List<Fragment> getSampleFragments(java.util.List<Fragment> fragments,
                                                          ProtocolData protData)

In case pxf_max_fragments parameter is declared, make sure not to get over the limit. The returned fragments are evenly distributed, in order to achieve good sampling.

Parameters:

fragments - fragments list

protData - container for parameters, including sampling data.

Returns:

a list of fragments no bigger than pxf_max_fragments parameter.

generateSamplingBitSet

public static java.util.BitSet generateSamplingBitSet(int poolSize,
                                                      int sampleSize)

Marks sampleSize bits out of the poolSize, in a uniform way.

Parameters:

poolSize - pool size

sampleSize - sample size

Returns:

bit set with sampleSize bits set out of poolSize.