org.apache.drill.exec.expr.fn.impl

Class AbstractSqlPatternMatcher

java.lang.Object

org.apache.drill.exec.expr.fn.impl.AbstractSqlPatternMatcher

All Implemented Interfaces:

SqlPatternMatcher

Direct Known Subclasses:

SqlPatternConstantMatcher, SqlPatternContainsMatcher, SqlPatternEndsWithMatcher, SqlPatternStartsWithMatcher

public abstract class AbstractSqlPatternMatcher
extends Object
implements SqlPatternMatcher

To get good performance for most commonly used pattern matches CONSTANT('ABC') SqlPatternConstantMatcher STARTSWITH('%ABC') SqlPatternStartsWithMatcher ENDSWITH('ABC%') SqlPatternEndsWithMatcher CONTAINS('%ABC%') SqlPatternContainsMatcher we have simple pattern matchers. Idea is to have our own implementation for simple pattern matchers so we can avoid heavy weight regex processing, skip UTF-8 decoding and char conversion. Instead, we encode the pattern string and do byte comparison against native memory. Overall, this approach gives us orders of magnitude performance improvement for simple pattern matches. Anything that is not simple is considered complex pattern and we use Java regex for complex pattern matches.

Field Summary

Fields

Modifier and Type	Field and Description
protected ByteBuffer	patternByteBuffer
protected int	patternLength
protected String	patternString

Constructor Summary

Constructors

Constructor and Description
AbstractSqlPatternMatcher(String patternString)

Method Summary

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.expr.fn.impl.SqlPatternMatcher

match

Field Detail

patternString

protected final String patternString

patternLength

protected final int patternLength

patternByteBuffer

protected final ByteBuffer patternByteBuffer

Constructor Detail

AbstractSqlPatternMatcher

public AbstractSqlPatternMatcher(String patternString)