org.apache.hadoop.hbase.regionserver.querymatcher

类 ScanWildcardColumnTracker

java.lang.Object

org.apache.hadoop.hbase.regionserver.querymatcher.ScanWildcardColumnTracker

所有已实现的接口:

ColumnTracker, ShipperListener

@InterfaceAudience.Private
public class ScanWildcardColumnTracker
extends Object
implements ColumnTracker

Keeps track of the columns for a scan if they are not explicitly specified

构造器概要

构造器

构造器和说明
ScanWildcardColumnTracker(int minVersion, int maxVersion, long oldestUnexpiredTS, CellComparator comparator) Return maxVersions of every row.

方法概要

限定符和类型	方法和说明
void	beforeShipped() The action that needs to be performed before Shipper.shipped() is performed
ScanQueryMatcher.MatchCode	checkColumn(Cell cell, byte type) Checks if the column is present in the list of requested columns by returning the match code instance.
ScanQueryMatcher.MatchCode	checkVersions(Cell cell, long timestamp, byte type, boolean ignoreCount) Keeps track of the number of versions for the columns asked for.
boolean	done() We can never know a-priori if we are done, so always return false.
org.apache.hadoop.hbase.regionserver.querymatcher.ColumnCount	getColumnHint() Used by matcher and scan/get to get a hint of the next column to seek to after checkColumn() returns SKIP.
ScanQueryMatcher.MatchCode	getNextRowOrNextColumn(Cell cell) Retrieve the MatchCode for the next row or column
boolean	isDone(long timestamp) Give the tracker a chance to declare it's done based on only the timestamp to allow an early out.
void	reset() Resets the Matcher

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.apache.hadoop.hbase.regionserver.querymatcher.ColumnTracker

doneWithColumn

构造器详细资料

ScanWildcardColumnTracker

public ScanWildcardColumnTracker(int minVersion,
                                 int maxVersion,
                                 long oldestUnexpiredTS,
                                 CellComparator comparator)

Return maxVersions of every row.

参数:

minVersion - Minimum number of versions to keep

maxVersion - Maximum number of versions to return

oldestUnexpiredTS - oldest timestamp that has not expired according to the TTL.

comparator - used to compare the qualifier of cell

方法详细资料

checkColumn

public ScanQueryMatcher.MatchCode checkColumn(Cell cell,
                                              byte type)
                                       throws IOException

Checks if the column is present in the list of requested columns by returning the match code instance. It does not check against the number of versions for the columns asked for. To do the version check, one has to call ColumnTracker.checkVersions(Cell, long, byte, boolean) method based on the return type (INCLUDE) of this method. The values that can be returned by this method are ScanQueryMatcher.MatchCode.INCLUDE, ScanQueryMatcher.MatchCode.SEEK_NEXT_COL and ScanQueryMatcher.MatchCode.SEEK_NEXT_ROW. This receives puts *and* deletes.

指定者:

checkColumn 在接口中 ColumnTracker

参数:

cell - a cell with the column to match against

type - The type of the Cell

返回:

The match code instance.

抛出:

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

checkVersions

public ScanQueryMatcher.MatchCode checkVersions(Cell cell,
                                                long timestamp,
                                                byte type,
                                                boolean ignoreCount)
                                         throws IOException

Keeps track of the number of versions for the columns asked for. It assumes that the user has already checked if the cell needs to be included by calling the ColumnTracker.checkColumn(Cell, byte) method. The enum values returned by this method are ScanQueryMatcher.MatchCode.SKIP, ScanQueryMatcher.MatchCode.INCLUDE, ScanQueryMatcher.MatchCode.INCLUDE_AND_SEEK_NEXT_COL and ScanQueryMatcher.MatchCode.INCLUDE_AND_SEEK_NEXT_ROW. Implementations which include all the columns could just return ScanQueryMatcher.MatchCode.INCLUDE in the ColumnTracker.checkColumn(Cell, byte) method and perform all the operations in this checkVersions method. This receives puts *and* deletes. Deletes do not count as a version, but rather take the version of the previous put (so eventually all but the last can be reclaimed).

指定者:

checkVersions 在接口中 ColumnTracker

参数:

cell - a cell with the column to match against

timestamp - The timestamp of the cell.

type - the type of the key value (Put/Delete)

ignoreCount - indicates if the KV needs to be excluded while counting (used during compactions. We only count KV's that are older than all the scanners' read points.)

返回:

the scan query matcher match code instance

抛出:

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

reset

public void reset()

从接口复制的说明: ColumnTracker

Resets the Matcher

指定者:

reset 在接口中 ColumnTracker

getColumnHint

public org.apache.hadoop.hbase.regionserver.querymatcher.ColumnCount getColumnHint()

Used by matcher and scan/get to get a hint of the next column to seek to after checkColumn() returns SKIP. Returns the next interesting column we want, or NULL there is none (wildcard scanner).

指定者:

getColumnHint 在接口中 ColumnTracker

返回:

The column count.

done

public boolean done()

We can never know a-priori if we are done, so always return false.

指定者:

done 在接口中 ColumnTracker

返回:

false

getNextRowOrNextColumn

public ScanQueryMatcher.MatchCode getNextRowOrNextColumn(Cell cell)

从接口复制的说明: ColumnTracker

Retrieve the MatchCode for the next row or column

指定者:

getNextRowOrNextColumn 在接口中 ColumnTracker

beforeShipped

public void beforeShipped()

从接口复制的说明: ShipperListener

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

指定者:

beforeShipped 在接口中 ShipperListener

isDone

public boolean isDone(long timestamp)

从接口复制的说明: ColumnTracker

Give the tracker a chance to declare it's done based on only the timestamp to allow an early out.

指定者:

isDone 在接口中 ColumnTracker

返回:

true to early out based on timestamp.