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java.lang.Objectorg.apache.hadoop.hbase.regionserver.KeyValueHeap
public class KeyValueHeap
Implements a heap merge across any number of KeyValueScanners.
Implements KeyValueScanner itself.
This class is used at the Region level to merge across Stores and at the Store level to merge across the memstore and StoreFiles.
In the Region case, we also need InternalScanner.next(List), so this class also implements InternalScanner. WARNING: As is, if you try to use this as an InternalScanner at the Store level, you will get runtime exceptions.
Constructor Summary | |
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KeyValueHeap(List<? extends KeyValueScanner> scanners,
KeyValue.KVComparator comparator)
Constructor. |
Method Summary | |
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void |
close()
Close the KeyValue scanner. |
PriorityQueue<KeyValueScanner> |
getHeap()
|
long |
getSequenceID()
Get the sequence id associated with this KeyValueScanner. |
KeyValue |
next()
Return the next KeyValue in this scanner, iterating the scanner |
boolean |
next(List<KeyValue> result)
Gets the next row of keys from the top-most scanner. |
boolean |
next(List<KeyValue> result,
int limit)
Gets the next row of keys from the top-most scanner. |
KeyValue |
peek()
Look at the next KeyValue in this scanner, but do not iterate scanner. |
boolean |
reseek(KeyValue seekKey)
Reseek the scanner at or after the specified KeyValue. |
boolean |
seek(KeyValue seekKey)
Seeks all scanners at or below the specified seek key. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public KeyValueHeap(List<? extends KeyValueScanner> scanners, KeyValue.KVComparator comparator)
scanners
- comparator
- Method Detail |
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public KeyValue peek()
KeyValueScanner
peek
in interface KeyValueScanner
public KeyValue next() throws IOException
KeyValueScanner
next
in interface KeyValueScanner
IOException
public boolean next(List<KeyValue> result, int limit) throws IOException
This method takes care of updating the heap.
This can ONLY be called when you are using Scanners that implement
InternalScanner as well as KeyValueScanner (a StoreScanner
).
next
in interface InternalScanner
result
- limit
-
IOException
- epublic boolean next(List<KeyValue> result) throws IOException
This method takes care of updating the heap.
This can ONLY be called when you are using Scanners that implement
InternalScanner as well as KeyValueScanner (a StoreScanner
).
next
in interface InternalScanner
result
-
IOException
- epublic void close()
KeyValueScanner
close
in interface Closeable
close
in interface InternalScanner
close
in interface KeyValueScanner
public boolean seek(KeyValue seekKey) throws IOException
As individual scanners may run past their ends, those scanners are automatically closed and removed from the heap.
seek
in interface KeyValueScanner
seekKey
- KeyValue to seek at or after
IOException
public boolean reseek(KeyValue seekKey) throws IOException
KeyValueScanner
reseek
in interface KeyValueScanner
seekKey
- seek value (should be non-null)
IOException
public PriorityQueue<KeyValueScanner> getHeap()
public long getSequenceID()
KeyValueScanner
getSequenceID
in interface KeyValueScanner
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