org.apache.hadoop.hbase.regionserver

Interface ChangedReadersObserver

All Known Implementing Classes:

MobStoreScanner, ReversedMobStoreScanner, ReversedStoreScanner, StoreScanner

@InterfaceAudience.Private
public interface ChangedReadersObserver

If set of MapFile.Readers in Store change, implementors are notified.

Method Summary

Modifier and Type	Method and Description
long	getReadPoint() Returns the read point of the current scan
void	updateReaders(List<HStoreFile> sfs, List<KeyValueScanner> memStoreScanners) Notify observers.

Method Detail

getReadPoint

long getReadPoint()

Returns the read point of the current scan

updateReaders

void updateReaders(List<HStoreFile> sfs,
                   List<KeyValueScanner> memStoreScanners)
            throws IOException

Notify observers.
NOTE:Before we invoke this method,HStoreFile.increaseRefCount() is invoked for every HStoreFile in 'sfs' input parameter to prevent HStoreFile is archived after a concurrent compaction, and after this method is invoked,HStoreFile.decreaseRefCount() is invoked.So if you open the StoreFileReader or StoreFileScanner asynchronously in this method,you may need to invoke HStoreFile.increaseRefCount() or HStoreFile.decreaseRefCount() by yourself to prevent the HStoreFiles be archived.

Parameters:

sfs - The new files

memStoreScanners - scanner of current memstore

Throws:

IOException - e