org.apache.hadoop.hbase.filter

Class MultiRowRangeFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.MultiRowRangeFilter

@InterfaceAudience.Public
public class MultiRowRangeFilter
extends FilterBase

Filter to support scan multiple row key ranges. It can construct the row key ranges from the passed list which can be accessed by each region server. HBase is quite efficient when scanning only one small row key range. If user needs to specify multiple row key ranges in one scan, the typical solutions are: 1. through FilterList which is a list of row key Filters, 2. using the SQL layer over HBase to join with two table, such as hive, phoenix etc. However, both solutions are inefficient. Both of them can't utilize the range info to perform fast forwarding during scan which is quite time consuming. If the number of ranges are quite big (e.g. millions), join is a proper solution though it is slow. However, there are cases that user wants to specify a small number of ranges to scan (e.g. <1000 ranges). Both solutions can't provide satisfactory performance in such case. MultiRowRangeFilter is to support such usec ase (scan multiple row key ranges), which can construct the row key ranges from user specified list and perform fast-forwarding during scan. Thus, the scan will be quite efficient.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	MultiRowRangeFilter.BasicRowRange
private static class	MultiRowRangeFilter.RangeIteration Abstraction over the ranges of rows to return from this filter, regardless of forward or reverse scans being used.
private static class	MultiRowRangeFilter.ReversedRowRange Internal RowRange that reverses the sort-order to handle reverse scans.
static class	MultiRowRangeFilter.RowRange

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.filter.Filter

Filter.ReturnCode

Field Summary

Fields

Modifier and Type	Field and Description
private Filter.ReturnCode	currentReturnCode
private boolean	done
private int	index
private MultiRowRangeFilter.BasicRowRange	range
private List<MultiRowRangeFilter.RowRange>	rangeList
private MultiRowRangeFilter.RangeIteration	ranges
private static int	ROW_BEFORE_FIRST_RANGE

Fields inherited from class org.apache.hadoop.hbase.filter.Filter

reversed

Constructor Summary

Constructors

Constructor and Description
MultiRowRangeFilter(byte[][] rowKeyPrefixes) Constructor for creating a MultiRowRangeFilter from multiple rowkey prefixes.
MultiRowRangeFilter(List<MultiRowRangeFilter.RowRange> list)

Method Summary

Modifier and Type	Method and Description
(package private) boolean	areSerializedFieldsEqual(Filter o) Default implementation so that writers of custom filters aren't forced to implement.
private static List<MultiRowRangeFilter.RowRange>	createRangeListFromRowKeyPrefixes(byte[][] rowKeyPrefixes)
boolean	equals(Object obj)
boolean	filterAllRemaining() Filters that never filter all remaining can inherit this implementation that never stops the filter early.
Filter.ReturnCode	filterCell(Cell ignored) A way to filter based on the column family, column qualifier and/or the column value.
Filter.ReturnCode	filterKeyValue(Cell ignored) Deprecated.
boolean	filterRowKey(Cell firstRowCell) Filters a row based on the row key.
Cell	getNextCellHint(Cell currentKV) Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell.
List<MultiRowRangeFilter.RowRange>	getRowRanges()
int	hashCode()
static MultiRowRangeFilter	parseFrom(byte[] pbBytes)
static List<MultiRowRangeFilter.RowRange>	sortAndMerge(List<MultiRowRangeFilter.RowRange> ranges) sort the ranges and if the ranges with overlap, then merge them.
private static void	throwExceptionForInvalidRanges(List<MultiRowRangeFilter.RowRange> invalidRanges, boolean details)
byte[]	toByteArray() Return length 0 byte array for Filters that don't require special serialization

Methods inherited from class org.apache.hadoop.hbase.filter.FilterBase

createFilterFromArguments, filterRow, filterRowCells, filterRowKey, hasFilterRow, isFamilyEssential, reset, toString, transformCell

Methods inherited from class org.apache.hadoop.hbase.filter.Filter

isReversed, setReversed

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

ROW_BEFORE_FIRST_RANGE

private static final int ROW_BEFORE_FIRST_RANGE

See Also:

Constant Field Values

rangeList

private final List<MultiRowRangeFilter.RowRange> rangeList

ranges

private final MultiRowRangeFilter.RangeIteration ranges

done

private boolean done

index

private int index

range

private MultiRowRangeFilter.BasicRowRange range

currentReturnCode

private Filter.ReturnCode currentReturnCode

Constructor Detail

MultiRowRangeFilter

public MultiRowRangeFilter(List<MultiRowRangeFilter.RowRange> list)

Parameters:

list - A list of RowRange

MultiRowRangeFilter

public MultiRowRangeFilter(byte[][] rowKeyPrefixes)

Constructor for creating a MultiRowRangeFilter from multiple rowkey prefixes. As MultiRowRangeFilter javadoc says (See the solution 1 of the first statement), if you try to create a filter list that scans row keys corresponding to given prefixes (e.g., FilterList composed of multiple PrefixFilters), this constructor provides a way to avoid creating an inefficient one.

Parameters:

rowKeyPrefixes - the array of byte array

Method Detail

createRangeListFromRowKeyPrefixes

private static List<MultiRowRangeFilter.RowRange> createRangeListFromRowKeyPrefixes(byte[][] rowKeyPrefixes)

getRowRanges

public List<MultiRowRangeFilter.RowRange> getRowRanges()

filterAllRemaining

public boolean filterAllRemaining()

Description copied from class: FilterBase

Filters that never filter all remaining can inherit this implementation that never stops the filter early. If this returns true, the scan will terminate. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

filterAllRemaining in class FilterBase

Returns:

true to end scan, false to continue.

filterRowKey

public boolean filterRowKey(Cell firstRowCell)

Description copied from class: Filter

Filters a row based on the row key. If this returns true, the entire row will be excluded. If false, each KeyValue in the row will be passed to Filter.filterCell(Cell) below. If Filter.filterAllRemaining() returns true, then Filter.filterRowKey(Cell) should also return true. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

filterRowKey in class FilterBase

Parameters:

firstRowCell - The first cell coming in the new row

Returns:

true, remove entire row, false, include the row (maybe).

filterKeyValue

@Deprecated
public Filter.ReturnCode filterKeyValue(Cell ignored)

Deprecated.

Description copied from class: Filter

A way to filter based on the column family, column qualifier and/or the column value. Return code is described below. This allows filters to filter only certain number of columns, then terminate without matching ever column. If filterRowKey returns true, filterKeyValue needs to be consistent with it. filterKeyValue can assume that filterRowKey has already been called for the row. If your filter returns ReturnCode.NEXT_ROW, it should return ReturnCode.NEXT_ROW until Filter.reset() is called just in case the caller calls for the next row. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

filterKeyValue in class Filter

Parameters:

ignored - the Cell in question

Returns:

code as described below, Filter.ReturnCode.INCLUDE by default

See Also:

Filter.ReturnCode

filterCell

public Filter.ReturnCode filterCell(Cell ignored)

Description copied from class: Filter

A way to filter based on the column family, column qualifier and/or the column value. Return code is described below. This allows filters to filter only certain number of columns, then terminate without matching ever column. If filterRowKey returns true, filterCell needs to be consistent with it. filterCell can assume that filterRowKey has already been called for the row. If your filter returns ReturnCode.NEXT_ROW, it should return ReturnCode.NEXT_ROW until Filter.reset() is called just in case the caller calls for the next row. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

filterCell in class Filter

Parameters:

ignored - the Cell in question

Returns:

code as described below

See Also:

Filter.ReturnCode

getNextCellHint

public Cell getNextCellHint(Cell currentKV)

Description copied from class: FilterBase

Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell. If the filter returns the match code SEEK_NEXT_USING_HINT, then it should also tell which is the next key it must seek to. After receiving the match code SEEK_NEXT_USING_HINT, the QueryMatcher would call this function to find out which key it must next seek to. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

getNextCellHint in class FilterBase

Returns:

KeyValue which must be next seeked. return null if the filter is not sure which key to seek to next.

toByteArray

public byte[] toByteArray()

Description copied from class: FilterBase

Return length 0 byte array for Filters that don't require special serialization

Overrides:

toByteArray in class FilterBase

Returns:

The filter serialized using pb

parseFrom

public static MultiRowRangeFilter parseFrom(byte[] pbBytes)
                                     throws DeserializationException

Parameters:

pbBytes - A pb serialized instance

Returns:

An instance of MultiRowRangeFilter

Throws:

DeserializationException

areSerializedFieldsEqual

boolean areSerializedFieldsEqual(Filter o)

Description copied from class: FilterBase

Default implementation so that writers of custom filters aren't forced to implement.

Overrides:

areSerializedFieldsEqual in class FilterBase

Parameters:

o - the filter to compare

Returns:

true if and only if the fields of the filter that are serialized are equal to the corresponding fields in other. Used for testing.

sortAndMerge

public static List<MultiRowRangeFilter.RowRange> sortAndMerge(List<MultiRowRangeFilter.RowRange> ranges)

sort the ranges and if the ranges with overlap, then merge them.

Parameters:

ranges - the list of ranges to sort and merge.

Returns:

the ranges after sort and merge.

throwExceptionForInvalidRanges

private static void throwExceptionForInvalidRanges(List<MultiRowRangeFilter.RowRange> invalidRanges,
                                                   boolean details)

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object