org.apache.hadoop.hbase.regionserver.querymatcher

Class ScanQueryMatcher

java.lang.Object

org.apache.hadoop.hbase.regionserver.querymatcher.ScanQueryMatcher

All Implemented Interfaces:

ShipperListener

Direct Known Subclasses:

CompactionScanQueryMatcher, UserScanQueryMatcher

@InterfaceAudience.Private
public abstract class ScanQueryMatcher
extends Object
implements ShipperListener

A query matcher that is specifically designed for the scan case.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ScanQueryMatcher.MatchCode match(org.apache.hadoop.hbase.Cell) return codes.

Field Summary

Fields

Modifier and Type	Field and Description
protected ColumnTracker	columns Keeps track of columns and versions
protected Cell	currentRow Row the query is on
protected long	now
protected long	oldestUnexpiredTS The oldest timestamp we are interested in, based on TTL
protected CellComparator	rowComparator Row comparator for the region this query is for
protected Cell	startKey Key to seek to in memstore and StoreFiles

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ScanQueryMatcher(Cell startKey, ScanInfo scanInfo, ColumnTracker columns, long oldestUnexpiredTS, long now)

Method Summary

Modifier and Type	Method and Description
void	beforeShipped() The action that needs to be performed before Shipper.shipped() is performed
protected ScanQueryMatcher.MatchCode	checkDeleted(DeleteTracker deletes, Cell cell)
void	clearCurrentRow() Make currentRow() return null.
int	compareKeyForNextColumn(Cell nextIndexed, Cell currentCell)
int	compareKeyForNextRow(Cell nextIndexed, Cell currentCell)
protected static Cell	createStartKeyFromRow(byte[] startRow, ScanInfo scanInfo)
Cell	currentRow()
abstract Filter	getFilter()
Cell	getKeyForNextColumn(Cell cell)
abstract Cell	getNextKeyHint(Cell cell) Delegate to Filter.getNextCellHint(Cell).
Cell	getStartKey()
protected static Pair<DeleteTracker,ColumnTracker>	getTrackers(RegionCoprocessorHost host, NavigableSet<byte[]> columns, ScanInfo scanInfo, long oldestUnexpiredTS, Scan userScan)
abstract boolean	hasNullColumnInQuery()
abstract boolean	isUserScan()
abstract ScanQueryMatcher.MatchCode	match(Cell cell) Determines if the caller should do one of several things: seek/skip to the next row (MatchCode.SEEK_NEXT_ROW) seek/skip to the next column (MatchCode.SEEK_NEXT_COL) include the current KeyValue (MatchCode.INCLUDE) ignore the current KeyValue (MatchCode.SKIP) got to the next row (MatchCode.DONE)
abstract boolean	moreRowsMayExistAfter(Cell cell)
protected ScanQueryMatcher.MatchCode	preCheck(Cell cell) Check before the delete logic.
protected abstract void	reset()
void	setToNewRow(Cell currentRow) Set the row when there is change in row

Methods inherited from class java.lang.Object

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

Field Detail

rowComparator

protected final CellComparator rowComparator

Row comparator for the region this query is for

startKey

protected final Cell startKey

Key to seek to in memstore and StoreFiles

columns

protected final ColumnTracker columns

Keeps track of columns and versions

oldestUnexpiredTS

protected final long oldestUnexpiredTS

The oldest timestamp we are interested in, based on TTL

now

protected final long now

currentRow

protected Cell currentRow

Row the query is on

Constructor Detail

ScanQueryMatcher

protected ScanQueryMatcher(Cell startKey,
                           ScanInfo scanInfo,
                           ColumnTracker columns,
                           long oldestUnexpiredTS,
                           long now)

Method Detail

preCheck

protected final ScanQueryMatcher.MatchCode preCheck(Cell cell)

Check before the delete logic.

Returns:

null means continue.

checkDeleted

protected final ScanQueryMatcher.MatchCode checkDeleted(DeleteTracker deletes,
                                                        Cell cell)

match

public abstract ScanQueryMatcher.MatchCode match(Cell cell)
                                          throws IOException

Determines if the caller should do one of several things:

• seek/skip to the next row (MatchCode.SEEK_NEXT_ROW)
• seek/skip to the next column (MatchCode.SEEK_NEXT_COL)
• include the current KeyValue (MatchCode.INCLUDE)
• ignore the current KeyValue (MatchCode.SKIP)
• got to the next row (MatchCode.DONE)

Parameters:

cell - KeyValue to check

Returns:

The match code instance.

Throws:

IOException - in case there is an internal consistency problem caused by a data corruption.

getStartKey

public Cell getStartKey()

Returns:

the start key

hasNullColumnInQuery

public abstract boolean hasNullColumnInQuery()

Returns:

whether there is an null column in the query

currentRow

public Cell currentRow()

Returns:

a cell represent the current row

clearCurrentRow

public void clearCurrentRow()

Make currentRow() return null.

reset

protected abstract void reset()

setToNewRow

public void setToNewRow(Cell currentRow)

Set the row when there is change in row

Parameters:

currentRow -

isUserScan

public abstract boolean isUserScan()

moreRowsMayExistAfter

public abstract boolean moreRowsMayExistAfter(Cell cell)

Returns:

Returns false if we know there are no more rows to be scanned (We've reached the stopRow or we are scanning on row only because this Scan is for a Get, etc.

getKeyForNextColumn

public Cell getKeyForNextColumn(Cell cell)

compareKeyForNextRow

public int compareKeyForNextRow(Cell nextIndexed,
                                Cell currentCell)

Parameters:

nextIndexed - the key of the next entry in the block index (if any)

currentCell - The Cell we're using to calculate the seek key

Returns:

result of the compare between the indexed key and the key portion of the passed cell

compareKeyForNextColumn

public int compareKeyForNextColumn(Cell nextIndexed,
                                   Cell currentCell)

Parameters:

nextIndexed - the key of the next entry in the block index (if any)

currentCell - The Cell we're using to calculate the seek key

Returns:

result of the compare between the indexed key and the key portion of the passed cell

getFilter

public abstract Filter getFilter()

Returns:

the Filter

getNextKeyHint

public abstract Cell getNextKeyHint(Cell cell)
                             throws IOException

Delegate to Filter.getNextCellHint(Cell). If no filter, return null.

Throws:

IOException

beforeShipped

public void beforeShipped()
                   throws IOException

Description copied from interface: ShipperListener

The action that needs to be performed before Shipper.shipped() is performed

Specified by:

beforeShipped in interface ShipperListener

Throws:

IOException

createStartKeyFromRow

protected static Cell createStartKeyFromRow(byte[] startRow,
                                            ScanInfo scanInfo)

getTrackers

protected static Pair<DeleteTracker,ColumnTracker> getTrackers(RegionCoprocessorHost host,
                                                               NavigableSet<byte[]> columns,
                                                               ScanInfo scanInfo,
                                                               long oldestUnexpiredTS,
                                                               Scan userScan)
                                                        throws IOException

Throws:

IOException