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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cassandra.db.compaction;
import java.util.*;
import java.util.function.Predicate;
import com.google.common.collect.Ordering;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.filter.ColumnFilter;
import org.apache.cassandra.db.partitions.PurgeFunction;
import org.apache.cassandra.db.partitions.UnfilteredPartitionIterator;
import org.apache.cassandra.db.partitions.UnfilteredPartitionIterators;
import org.apache.cassandra.db.rows.*;
import org.apache.cassandra.db.transform.Transformation;
import org.apache.cassandra.index.transactions.CompactionTransaction;
import org.apache.cassandra.io.sstable.ISSTableScanner;
import org.apache.cassandra.metrics.CompactionMetrics;
import org.apache.cassandra.schema.CompactionParams.TombstoneOption;
/**
* 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.
*
*/
public class CompactionIterator extends CompactionInfo.Holder implements UnfilteredPartitionIterator
{
private static final long UNFILTERED_TO_UPDATE_PROGRESS = 100;
private final OperationType type;
private final CompactionController controller;
private final List scanners;
private final int nowInSec;
private final UUID compactionId;
private final long totalBytes;
private long bytesRead;
private long totalSourceCQLRows;
/*
* counters for merged rows.
* array index represents (number of merged rows - 1), so index 0 is counter for no merge (1 row),
* index 1 is counter for 2 rows merged, and so on.
*/
private final long[] mergeCounters;
private final UnfilteredPartitionIterator compacted;
private final CompactionMetrics metrics;
public CompactionIterator(OperationType type, List scanners, CompactionController controller, int nowInSec, UUID compactionId)
{
this(type, scanners, controller, nowInSec, compactionId, null);
}
@SuppressWarnings("resource") // We make sure to close mergedIterator in close() and CompactionIterator is itself an AutoCloseable
public CompactionIterator(OperationType type, List scanners, CompactionController controller, int nowInSec, UUID compactionId, CompactionMetrics metrics)
{
this.controller = controller;
this.type = type;
this.scanners = scanners;
this.nowInSec = nowInSec;
this.compactionId = compactionId;
this.bytesRead = 0;
long bytes = 0;
for (ISSTableScanner scanner : scanners)
bytes += scanner.getLengthInBytes();
this.totalBytes = bytes;
this.mergeCounters = new long[scanners.size()];
this.metrics = metrics;
if (metrics != null)
metrics.beginCompaction(this);
UnfilteredPartitionIterator merged = scanners.isEmpty()
? EmptyIterators.unfilteredPartition(controller.cfs.metadata, false)
: UnfilteredPartitionIterators.merge(scanners, nowInSec, listener());
boolean isForThrift = merged.isForThrift(); // to stop capture of iterator in Purger, which is confusing for debug
merged = Transformation.apply(merged, new GarbageSkipper(controller, nowInSec));
this.compacted = Transformation.apply(merged, new Purger(isForThrift, controller, nowInSec));
}
public boolean isForThrift()
{
return false;
}
public CFMetaData metadata()
{
return controller.cfs.metadata;
}
public CompactionInfo getCompactionInfo()
{
return new CompactionInfo(controller.cfs.metadata,
type,
bytesRead,
totalBytes,
compactionId);
}
private void updateCounterFor(int rows)
{
assert rows > 0 && rows - 1 < mergeCounters.length;
mergeCounters[rows - 1] += 1;
}
public long[] getMergedRowCounts()
{
return mergeCounters;
}
public long getTotalSourceCQLRows()
{
return totalSourceCQLRows;
}
private UnfilteredPartitionIterators.MergeListener listener()
{
return new UnfilteredPartitionIterators.MergeListener()
{
public UnfilteredRowIterators.MergeListener getRowMergeListener(DecoratedKey partitionKey, List versions)
{
int merged = 0;
for (UnfilteredRowIterator iter : versions)
{
if (iter != null)
merged++;
}
assert merged > 0;
CompactionIterator.this.updateCounterFor(merged);
if (type != OperationType.COMPACTION || !controller.cfs.indexManager.hasIndexes())
return null;
Columns statics = Columns.NONE;
Columns regulars = Columns.NONE;
for (UnfilteredRowIterator iter : versions)
{
if (iter != null)
{
statics = statics.mergeTo(iter.columns().statics);
regulars = regulars.mergeTo(iter.columns().regulars);
}
}
final PartitionColumns partitionColumns = new PartitionColumns(statics, regulars);
// If we have a 2ndary index, we must update it with deleted/shadowed cells.
// we can reuse a single CleanupTransaction for the duration of a partition.
// Currently, it doesn't do any batching of row updates, so every merge event
// for a single partition results in a fresh cycle of:
// * Get new Indexer instances
// * Indexer::start
// * Indexer::onRowMerge (for every row being merged by the compaction)
// * Indexer::commit
// A new OpOrder.Group is opened in an ARM block wrapping the commits
// TODO: this should probably be done asynchronously and batched.
final CompactionTransaction indexTransaction =
controller.cfs.indexManager.newCompactionTransaction(partitionKey,
partitionColumns,
versions.size(),
nowInSec);
return new UnfilteredRowIterators.MergeListener()
{
public void onMergedPartitionLevelDeletion(DeletionTime mergedDeletion, DeletionTime[] versions)
{
}
public void onMergedRows(Row merged, Row[] versions)
{
indexTransaction.start();
indexTransaction.onRowMerge(merged, versions);
indexTransaction.commit();
}
public void onMergedRangeTombstoneMarkers(RangeTombstoneMarker mergedMarker, RangeTombstoneMarker[] versions)
{
}
public void close()
{
}
};
}
public void close()
{
}
};
}
private void updateBytesRead()
{
long n = 0;
for (ISSTableScanner scanner : scanners)
n += scanner.getCurrentPosition();
bytesRead = n;
}
public boolean hasNext()
{
return compacted.hasNext();
}
public UnfilteredRowIterator next()
{
return compacted.next();
}
public void remove()
{
throw new UnsupportedOperationException();
}
public void close()
{
try
{
compacted.close();
}
finally
{
if (metrics != null)
metrics.finishCompaction(this);
}
}
public String toString()
{
return this.getCompactionInfo().toString();
}
private class Purger extends PurgeFunction
{
private final CompactionController controller;
private DecoratedKey currentKey;
private Predicate purgeEvaluator;
private long compactedUnfiltered;
private Purger(boolean isForThrift, CompactionController controller, int nowInSec)
{
super(isForThrift, nowInSec, controller.gcBefore, controller.compactingRepaired() ? Integer.MAX_VALUE : Integer.MIN_VALUE, controller.cfs.getCompactionStrategyManager().onlyPurgeRepairedTombstones());
this.controller = controller;
}
@Override
protected void onEmptyPartitionPostPurge(DecoratedKey key)
{
if (type == OperationType.COMPACTION)
controller.cfs.invalidateCachedPartition(key);
}
@Override
protected void onNewPartition(DecoratedKey key)
{
currentKey = key;
purgeEvaluator = null;
}
@Override
protected void updateProgress()
{
totalSourceCQLRows++;
if ((++compactedUnfiltered) % UNFILTERED_TO_UPDATE_PROGRESS == 0)
updateBytesRead();
}
/*
* Evaluates whether a tombstone with the given deletion timestamp can be purged. This is the minimum
* timestamp for any sstable containing `currentKey` outside of the set of sstables involved in this compaction.
* This is computed lazily on demand as we only need this if there is tombstones and this a bit expensive
* (see #8914).
*/
protected Predicate getPurgeEvaluator()
{
if (purgeEvaluator == null)
{
purgeEvaluator = controller.getPurgeEvaluator(currentKey);
}
return purgeEvaluator;
}
}
/**
* Unfiltered row iterator that removes deleted data as provided by a "tombstone source" for the partition.
* The result produced by this iterator is such that when merged with tombSource it produces the same output
* as the merge of dataSource and tombSource.
*/
private static class GarbageSkippingUnfilteredRowIterator extends WrappingUnfilteredRowIterator
{
final UnfilteredRowIterator tombSource;
final DeletionTime partitionLevelDeletion;
final Row staticRow;
final ColumnFilter cf;
final int nowInSec;
final CFMetaData metadata;
final boolean cellLevelGC;
DeletionTime tombOpenDeletionTime = DeletionTime.LIVE;
DeletionTime dataOpenDeletionTime = DeletionTime.LIVE;
DeletionTime openDeletionTime = DeletionTime.LIVE;
DeletionTime partitionDeletionTime;
DeletionTime activeDeletionTime;
Unfiltered tombNext = null;
Unfiltered dataNext = null;
Unfiltered next = null;
/**
* Construct an iterator that filters out data shadowed by the provided "tombstone source".
*
* @param dataSource The input row. The result is a filtered version of this.
* @param tombSource Tombstone source, i.e. iterator used to identify deleted data in the input row.
* @param nowInSec Current time, used in choosing the winner when cell expiration is involved.
* @param cellLevelGC If false, the iterator will only look at row-level deletion times and tombstones.
* If true, deleted or overwritten cells within a surviving row will also be removed.
*/
protected GarbageSkippingUnfilteredRowIterator(UnfilteredRowIterator dataSource, UnfilteredRowIterator tombSource, int nowInSec, boolean cellLevelGC)
{
super(dataSource);
this.tombSource = tombSource;
this.nowInSec = nowInSec;
this.cellLevelGC = cellLevelGC;
metadata = dataSource.metadata();
cf = ColumnFilter.all(metadata);
activeDeletionTime = partitionDeletionTime = tombSource.partitionLevelDeletion();
// Only preserve partition level deletion if not shadowed. (Note: Shadowing deletion must not be copied.)
this.partitionLevelDeletion = dataSource.partitionLevelDeletion().supersedes(tombSource.partitionLevelDeletion()) ?
dataSource.partitionLevelDeletion() :
DeletionTime.LIVE;
Row dataStaticRow = garbageFilterRow(dataSource.staticRow(), tombSource.staticRow());
this.staticRow = dataStaticRow != null ? dataStaticRow : Rows.EMPTY_STATIC_ROW;
tombNext = advance(tombSource);
dataNext = advance(dataSource);
}
private static Unfiltered advance(UnfilteredRowIterator source)
{
return source.hasNext() ? source.next() : null;
}
@Override
public DeletionTime partitionLevelDeletion()
{
return partitionLevelDeletion;
}
public void close()
{
super.close();
tombSource.close();
}
@Override
public Row staticRow()
{
return staticRow;
}
@Override
public boolean hasNext()
{
// Produce the next element. This may consume multiple elements from both inputs until we find something
// from dataSource that is still live. We track the currently open deletion in both sources, as well as the
// one we have last issued to the output. The tombOpenDeletionTime is used to filter out content; the others
// to decide whether or not a tombstone is superseded, and to be able to surface (the rest of) a deletion
// range from the input when a suppressing deletion ends.
while (next == null && dataNext != null)
{
int cmp = tombNext == null ? -1 : metadata.comparator.compare(dataNext, tombNext);
if (cmp < 0)
{
if (dataNext.isRow())
next = ((Row) dataNext).filter(cf, activeDeletionTime, false, metadata);
else
next = processDataMarker();
}
else if (cmp == 0)
{
if (dataNext.isRow())
{
next = garbageFilterRow((Row) dataNext, (Row) tombNext);
}
else
{
tombOpenDeletionTime = updateOpenDeletionTime(tombOpenDeletionTime, tombNext);
activeDeletionTime = Ordering.natural().max(partitionDeletionTime,
tombOpenDeletionTime);
next = processDataMarker();
}
}
else // (cmp > 0)
{
if (tombNext.isRangeTombstoneMarker())
{
tombOpenDeletionTime = updateOpenDeletionTime(tombOpenDeletionTime, tombNext);
activeDeletionTime = Ordering.natural().max(partitionDeletionTime,
tombOpenDeletionTime);
boolean supersededBefore = openDeletionTime.isLive();
boolean supersededAfter = !dataOpenDeletionTime.supersedes(activeDeletionTime);
// If a range open was not issued because it was superseded and the deletion isn't superseded any more, we need to open it now.
if (supersededBefore && !supersededAfter)
next = new RangeTombstoneBoundMarker(((RangeTombstoneMarker) tombNext).closeBound(false).invert(), dataOpenDeletionTime);
// If the deletion begins to be superseded, we don't close the range yet. This can save us a close/open pair if it ends after the superseding range.
}
}
if (next instanceof RangeTombstoneMarker)
openDeletionTime = updateOpenDeletionTime(openDeletionTime, next);
if (cmp <= 0)
dataNext = advance(wrapped);
if (cmp >= 0)
tombNext = advance(tombSource);
}
return next != null;
}
protected Row garbageFilterRow(Row dataRow, Row tombRow)
{
if (cellLevelGC)
{
return Rows.removeShadowedCells(dataRow, tombRow, activeDeletionTime, nowInSec);
}
else
{
DeletionTime deletion = Ordering.natural().max(tombRow.deletion().time(),
activeDeletionTime);
return dataRow.filter(cf, deletion, false, metadata);
}
}
/**
* Decide how to act on a tombstone marker from the input iterator. We can decide what to issue depending on
* whether or not the ranges before and after the marker are superseded/live -- if none are, we can reuse the
* marker; if both are, the marker can be ignored; otherwise we issue a corresponding start/end marker.
*/
private RangeTombstoneMarker processDataMarker()
{
dataOpenDeletionTime = updateOpenDeletionTime(dataOpenDeletionTime, dataNext);
boolean supersededBefore = openDeletionTime.isLive();
boolean supersededAfter = !dataOpenDeletionTime.supersedes(activeDeletionTime);
RangeTombstoneMarker marker = (RangeTombstoneMarker) dataNext;
if (!supersededBefore)
if (!supersededAfter)
return marker;
else
return new RangeTombstoneBoundMarker(marker.closeBound(false), marker.closeDeletionTime(false));
else
if (!supersededAfter)
return new RangeTombstoneBoundMarker(marker.openBound(false), marker.openDeletionTime(false));
else
return null;
}
@Override
public Unfiltered next()
{
if (!hasNext())
throw new IllegalStateException();
Unfiltered v = next;
next = null;
return v;
}
private DeletionTime updateOpenDeletionTime(DeletionTime openDeletionTime, Unfiltered next)
{
RangeTombstoneMarker marker = (RangeTombstoneMarker) next;
assert openDeletionTime.isLive() == !marker.isClose(false);
assert openDeletionTime.isLive() || openDeletionTime.equals(marker.closeDeletionTime(false));
return marker.isOpen(false) ? marker.openDeletionTime(false) : DeletionTime.LIVE;
}
}
/**
* Partition transformation applying GarbageSkippingUnfilteredRowIterator, obtaining tombstone sources for each
* partition using the controller's shadowSources method.
*/
private static class GarbageSkipper extends Transformation
{
final int nowInSec;
final CompactionController controller;
final boolean cellLevelGC;
private GarbageSkipper(CompactionController controller, int nowInSec)
{
this.controller = controller;
this.nowInSec = nowInSec;
cellLevelGC = controller.tombstoneOption == TombstoneOption.CELL;
}
@Override
protected UnfilteredRowIterator applyToPartition(UnfilteredRowIterator partition)
{
Iterable sources = controller.shadowSources(partition.partitionKey(), !cellLevelGC);
if (sources == null)
return partition;
List iters = new ArrayList<>();
for (UnfilteredRowIterator iter : sources)
{
if (!iter.isEmpty())
iters.add(iter);
else
iter.close();
}
if (iters.isEmpty())
return partition;
return new GarbageSkippingUnfilteredRowIterator(partition, UnfilteredRowIterators.merge(iters, nowInSec), nowInSec, cellLevelGC);
}
}
}