org.apache.cassandra.db.compaction

Class CompactionIterator

java.lang.Object

org.apache.cassandra.db.compaction.CompactionInfo.Holder

org.apache.cassandra.db.compaction.CompactionIterator

All Implemented Interfaces:

java.lang.AutoCloseable, java.util.Iterator<UnfilteredRowIterator>, BasePartitionIterator<UnfilteredRowIterator>, UnfilteredPartitionIterator, CloseableIterator<UnfilteredRowIterator>

public class CompactionIterator
extends CompactionInfo.Holder
implements UnfilteredPartitionIterator

Merge multiple iterators over the content of sstable into a "compacted" iterator.

On top of the actual merging the source iterators, this class:

• purge gc-able tombstones if possible (see PurgeIterator below).
• update 2ndary indexes if necessary (as we don't read-before-write on index updates, index entries are not deleted on deletion of the base table data, which is ok because we'll fix index inconsistency on reads. This however mean that potentially obsolete index entries could be kept a long time for data that is not read often, so compaction "pro-actively" fix such index entries. This is mainly an optimization).
• invalidate cached partitions that are empty post-compaction. This avoids keeping partitions with only purgable tombstones in the row cache.
• keep tracks of the compaction progress.

Constructor Summary

Constructors

Constructor and Description
CompactionIterator(OperationType type, java.util.List<ISSTableScanner> scanners, CompactionController controller, int nowInSec, java.util.UUID compactionId)
CompactionIterator(OperationType type, java.util.List<ISSTableScanner> scanners, CompactionController controller, int nowInSec, java.util.UUID compactionId, CompactionMetrics metrics)

Method Summary

Modifier and Type	Method and Description
void	close()
CompactionInfo	getCompactionInfo()
long[]	getMergedRowCounts()
long	getTotalSourceCQLRows()
boolean	hasNext()
boolean	isForThrift() Whether that partition iterator is for a thrift queries.
CFMetaData	metadata()
UnfilteredRowIterator	next()
void	remove()
java.lang.String	toString()

Methods inherited from class org.apache.cassandra.db.compaction.CompactionInfo.Holder

isStopRequested, stop

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

CompactionIterator

public CompactionIterator(OperationType type,
                          java.util.List<ISSTableScanner> scanners,
                          CompactionController controller,
                          int nowInSec,
                          java.util.UUID compactionId)

CompactionIterator

public CompactionIterator(OperationType type,
                          java.util.List<ISSTableScanner> scanners,
                          CompactionController controller,
                          int nowInSec,
                          java.util.UUID compactionId,
                          CompactionMetrics metrics)

Method Detail

isForThrift

public boolean isForThrift()

Description copied from interface: UnfilteredPartitionIterator

Whether that partition iterator is for a thrift queries.

If this is true, the partition iterator may return some empty UnfilteredRowIterator and those should be preserved as thrift include partitions that "exists" (have some cells even if this are actually deleted) but have nothing matching the query.

Specified by:

isForThrift in interface UnfilteredPartitionIterator

Returns:

whether the iterator is for a thrift query.

metadata

public CFMetaData metadata()

Specified by:

metadata in interface UnfilteredPartitionIterator

getCompactionInfo

public CompactionInfo getCompactionInfo()

Specified by:

getCompactionInfo in class CompactionInfo.Holder

getMergedRowCounts

public long[] getMergedRowCounts()

getTotalSourceCQLRows

public long getTotalSourceCQLRows()

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<UnfilteredRowIterator>

next

public UnfilteredRowIterator next()

Specified by:

next in interface java.util.Iterator<UnfilteredRowIterator>

remove

public void remove()

Specified by:

remove in interface java.util.Iterator<UnfilteredRowIterator>

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface BasePartitionIterator<UnfilteredRowIterator>

Specified by:

close in interface CloseableIterator<UnfilteredRowIterator>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object