RegionScannerImpl (Apache HBase - Server 2.6.3-hadoop3 API)

java.lang.Object
- org.apache.hadoop.hbase.regionserver.RegionScannerImpl

All Implemented Interfaces:

Closeable, AutoCloseable, RpcCallback, InternalScanner, RegionScanner, Shipper
```
@InterfaceAudience.Private
public class RegionScannerImpl
extends Object
implements RegionScanner, Shipper, RpcCallback
```
RegionScannerImpl is used to combine scanners from multiple Stores (aka column families).

Field Summary

Fields
Modifier and Type	Field and Description
`protected CellComparator`	`comparator`
`protected boolean`	`includeStopRow`
`protected Cell`	`joinedContinuationRow` If the joined heap data gathering is interrupted due to scan limits, this will contain the row for which we are populating the values.
`protected HRegion`	`region`
`protected byte[]`	`stopRow`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Closes the scanner and releases any resources it has allocated
`int`	`getBatch()`
`ScannerContext`	`getContext()`
`long`	`getMaxResultSize()`
`long`	`getMvccReadPoint()` Returns The Scanner's MVCC readPt see `MultiVersionConcurrencyControl`
`String`	`getOperationId()`
`RegionInfo`	`getRegionInfo()` Returns The RegionInfo for this scanner.
`protected void`	`initializeKVHeap(List<KeyValueScanner> scanners, List<KeyValueScanner> joinedScanners, HRegion region)`
`boolean`	`isFilterDone()` Returns True if a filter rules the scanner is over, done.
`boolean`	`next(List<Cell> outResults)` Grab the next row's worth of values.
`boolean`	`next(List<Cell> outResults, ScannerContext scannerContext)` Grab the next row's worth of values.
`boolean`	`nextRaw(List<Cell> outResults)` Grab the next row's worth of values.
`boolean`	`nextRaw(List<Cell> outResults, ScannerContext scannerContext)` Grab the next row's worth of values.
`protected boolean`	`nextRow(ScannerContext scannerContext, Cell curRowCell)`
`boolean`	`reseek(byte[] row)` Do a reseek to the required row.
`protected void`	`resetFilters()` Reset both the filter and the old filter.
`void`	`run()` Called at the end of an Rpc Call `RpcCallContext`
`void`	`shipped()` Called after a batch of rows scanned and set to be returned to client.
`protected boolean`	`shouldStop(Cell currentRowCell)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - joinedContinuationRow
```
protected Cell joinedContinuationRow
```
    If the joined heap data gathering is interrupted due to scan limits, this will contain the row for which we are populating the values.
  - stopRow
```
protected final byte[] stopRow
```
  - includeStopRow
```
protected final boolean includeStopRow
```
  - region
```
protected final HRegion region
```
  - comparator
```
protected final CellComparator comparator
```
- Method Detail
  - getRegionInfo
```
public RegionInfo getRegionInfo()
```
    Description copied from interface: RegionScanner
    
    Returns The RegionInfo for this scanner.
    
    Specified by:
    
    getRegionInfo in interface RegionScanner
  - getContext
```
public ScannerContext getContext()
```
  - initializeKVHeap
```
protected void initializeKVHeap(List<KeyValueScanner> scanners,
                                List<KeyValueScanner> joinedScanners,
                                HRegion region)
                         throws IOException
```
    Throws:
    
    IOException
  - getMaxResultSize
```
public long getMaxResultSize()
```
    Specified by:
    
    getMaxResultSize in interface RegionScanner
    
    Returns:
    
    The preferred max buffersize. See Scan.setMaxResultSize(long)
  - getMvccReadPoint
```
public long getMvccReadPoint()
```
    Description copied from interface: RegionScanner
    
    Returns The Scanner's MVCC readPt see MultiVersionConcurrencyControl
    
    Specified by:
    
    getMvccReadPoint in interface RegionScanner
  - getBatch
```
public int getBatch()
```
    Specified by:
    
    getBatch in interface RegionScanner
    
    Returns:
    
    The limit on the number of cells to retrieve on each call to next(). See Scan.setBatch(int)
  - getOperationId
```
public String getOperationId()
```
    Specified by:
    
    getOperationId in interface RegionScanner
    
    Returns:
    
    The Scanner's OperationWithAttributes.ID_ATRIBUTE value, or null if not set.
  - resetFilters
```
protected final void resetFilters()
                           throws IOException
```
    Reset both the filter and the old filter.
    
    Throws:
    
    IOException - in case a filter raises an I/O exception.
  - next
```
public boolean next(List<Cell> outResults)
             throws IOException
```
    Description copied from interface: InternalScanner
    
    Grab the next row's worth of values.
    
    Specified by:
    
    next in interface InternalScanner
    
    Parameters:
    
    outResults - return output array
    
    Returns:
    
    true if more rows exist after this one, false if scanner is done
    
    Throws:
    
    IOException - e
  - next
```
public boolean next(List<Cell> outResults,
                    ScannerContext scannerContext)
             throws IOException
```
    Description copied from interface: InternalScanner
    
    Grab the next row's worth of values.
    
    Specified by:
    
    next in interface InternalScanner
    
    Parameters:
    
    outResults - return output array
    
    Returns:
    
    true if more rows exist after this one, false if scanner is done
    
    Throws:
    
    IOException - e
  - nextRaw
```
public boolean nextRaw(List<Cell> outResults)
                throws IOException
```
    Description copied from interface: RegionScanner
    
    Grab the next row's worth of values. This is a special internal method to be called from coprocessor hooks to avoid expensive setup. Caller must set the thread's readpoint, start and close a region operation, an synchronize on the scanner object. Caller should maintain and update metrics. See RegionScanner.nextRaw(List, ScannerContext)
    
    Specified by:
    
    nextRaw in interface RegionScanner
    
    Parameters:
    
    outResults - return output array
    
    Returns:
    
    true if more rows exist after this one, false if scanner is done
    
    Throws:
    
    IOException - e
  - nextRaw
```
public boolean nextRaw(List<Cell> outResults,
                       ScannerContext scannerContext)
                throws IOException
```
    Description copied from interface: RegionScanner
    
    Grab the next row's worth of values. The ScannerContext is used to enforce and track any limits associated with this call. Any progress that exists in the ScannerContext prior to calling this method will be LOST if ScannerContext.getKeepProgress() is false. Upon returning from this method, the ScannerContext will contain information about the progress made towards the limits. This is a special internal method to be called from coprocessor hooks to avoid expensive setup. Caller must set the thread's readpoint, start and close a region operation, an synchronize on the scanner object. Example: HRegion region = ...; RegionScanner scanner = ... MultiVersionConcurrencyControl.setThreadReadPoint(scanner.getMvccReadPoint()); region.startRegionOperation(); try { synchronized(scanner) { ... boolean moreRows = scanner.nextRaw(values); ... } } finally { region.closeRegionOperation(); }
    
    Specified by:
    
    nextRaw in interface RegionScanner
    
    Parameters:
    
    outResults - return output array
    
    scannerContext - The ScannerContext instance encapsulating all limits that should be tracked during calls to this method. The progress towards these limits can be tracked within this instance.
    
    Returns:
    
    true if more rows exist after this one, false if scanner is done
    
    Throws:
    
    IOException - e
  - isFilterDone
```
public boolean isFilterDone()
                     throws IOException
```
    Returns True if a filter rules the scanner is over, done.
    
    Specified by:
    
    isFilterDone in interface RegionScanner
    
    Returns:
    
    True if a filter indicates that this scanner will return no further rows.
    
    Throws:
    
    IOException - in case of I/O failure on a filter.
  - nextRow
```
protected boolean nextRow(ScannerContext scannerContext,
                          Cell curRowCell)
                   throws IOException
```
    Throws:
    
    IOException
  - shouldStop
```
protected boolean shouldStop(Cell currentRowCell)
```
  - close
```
public void close()
```
    Description copied from interface: InternalScanner
    
    Closes the scanner and releases any resources it has allocated
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface InternalScanner
  - reseek
```
public boolean reseek(byte[] row)
               throws IOException
```
    Description copied from interface: RegionScanner
    
    Do a reseek to the required row. Should not be used to seek to a key which may come before the current position. Always seeks to the beginning of a row boundary. if row is null
    
    Specified by:
    
    reseek in interface RegionScanner
    
    Throws:
    
    IOException
  - shipped
```
public void shipped()
             throws IOException
```
    Description copied from interface: Shipper
    
    Called after a batch of rows scanned and set to be returned to client. Any in between cleanup can be done here.
    
    Specified by:
    
    shipped in interface Shipper
    
    Throws:
    
    IOException
  - run
```
public void run()
         throws IOException
```
    Description copied from interface: RpcCallback
    
    Called at the end of an Rpc Call RpcCallContext
    
    Specified by:
    
    run in interface RpcCallback
    
    Throws:
    
    IOException

Class RegionScannerImpl

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

joinedContinuationRow

stopRow

includeStopRow

region

comparator

Method Detail

getRegionInfo

getContext

initializeKVHeap

getMaxResultSize

getMvccReadPoint

getBatch

getOperationId

resetFilters

next

next

nextRaw

nextRaw

isFilterDone

nextRow

shouldStop

close

reseek

shipped

run