org.apache.cassandra.db.rows

Class ThrottledUnfilteredIterator

java.lang.Object

org.apache.cassandra.utils.AbstractIterator<UnfilteredRowIterator>

org.apache.cassandra.db.rows.ThrottledUnfilteredIterator

All Implemented Interfaces:

com.google.common.collect.PeekingIterator<UnfilteredRowIterator>, java.lang.AutoCloseable, java.util.Iterator<UnfilteredRowIterator>, CloseableIterator<UnfilteredRowIterator>

public class ThrottledUnfilteredIterator
extends AbstractIterator<UnfilteredRowIterator>
implements CloseableIterator<UnfilteredRowIterator>

A utility class to split the given into smaller chunks each having at most throttle + 1 unfiltereds. Only the first output contains partition level info: UnfilteredRowIterator.partitionLevelDeletion() and BaseRowIterator.staticRow(). Besides splitting, this iterator will also ensure each chunk does not finish with an open tombstone marker, by closing any opened tombstone markers and re-opening on the next chunk. The lifecycle of outputed {UnfilteredRowIterator only last till next call to AbstractIterator.next(). A subsequent AbstractIterator.next call will exhaust the previously returned iterator before computing the next, effectively skipping unfiltereds up to the throttle size. Closing this iterator will close the underlying iterator.

Method Summary

Modifier and Type	Method and Description
void	close()
protected UnfilteredRowIterator	computeNext()
static CloseableIterator<UnfilteredRowIterator>	throttle(UnfilteredPartitionIterator partitionIterator, int maxBatchSize) Splits a UnfilteredPartitionIterator in UnfilteredRowIterator batches with size no higher than maxBatchSize

Methods inherited from class org.apache.cassandra.utils.AbstractIterator

endOfData, hasNext, next, peek, remove

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining, hasNext, next, remove

Method Detail

computeNext

protected UnfilteredRowIterator computeNext()

Specified by:

computeNext in class AbstractIterator<UnfilteredRowIterator>

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface CloseableIterator<UnfilteredRowIterator>

Overrides:

close in class AbstractIterator<UnfilteredRowIterator>

throttle

public static CloseableIterator<UnfilteredRowIterator> throttle(UnfilteredPartitionIterator partitionIterator,
                                                                int maxBatchSize)

Splits a UnfilteredPartitionIterator in UnfilteredRowIterator batches with size no higher than maxBatchSize

Parameters:

partitionIterator -

maxBatchSize - max number of unfiltereds in the UnfilteredRowIterator. if 0 is given, it means no throttle.

Returns: