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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.rows;
import java.util.*;
import com.google.common.collect.Iterators;
import com.google.common.collect.PeekingIterator;
import org.apache.cassandra.config.ColumnDefinition;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.partitions.PartitionStatisticsCollector;
import org.apache.cassandra.utils.MergeIterator;
/**
* Static utilities to work on Row objects.
*/
public abstract class Rows
{
private Rows() {}
public static final Row EMPTY_STATIC_ROW = BTreeRow.emptyRow(Clustering.STATIC_CLUSTERING);
public static Row.Builder copy(Row row, Row.Builder builder)
{
builder.newRow(row.clustering());
builder.addPrimaryKeyLivenessInfo(row.primaryKeyLivenessInfo());
builder.addRowDeletion(row.deletion());
for (ColumnData cd : row)
{
if (cd.column().isSimple())
{
builder.addCell((Cell)cd);
}
else
{
ComplexColumnData complexData = (ComplexColumnData)cd;
builder.addComplexDeletion(complexData.column(), complexData.complexDeletion());
for (Cell cell : complexData)
builder.addCell(cell);
}
}
return builder;
}
/**
* Collect statistics on a given row.
*
* @param row the row for which to collect stats.
* @param collector the stats collector.
* @return the total number of cells in {@code row}.
*/
public static int collectStats(Row row, PartitionStatisticsCollector collector)
{
assert !row.isEmpty();
collector.update(row.primaryKeyLivenessInfo());
collector.update(row.deletion().time());
int columnCount = 0;
int cellCount = 0;
for (ColumnData cd : row)
{
if (cd.column().isSimple())
{
++columnCount;
++cellCount;
Cells.collectStats((Cell) cd, collector);
}
else
{
ComplexColumnData complexData = (ComplexColumnData)cd;
collector.update(complexData.complexDeletion());
if (complexData.hasCells())
{
++columnCount;
for (Cell cell : complexData)
{
++cellCount;
Cells.collectStats(cell, collector);
}
}
}
}
collector.updateColumnSetPerRow(columnCount);
return cellCount;
}
/**
* Given the result ({@code merged}) of merging multiple {@code inputs}, signals the difference between
* each input and {@code merged} to {@code diffListener}.
*
* Note that this method doesn't only emit cells etc where there's a difference. The listener is informed
* of every corresponding entity between the merged and input rows, including those that are equal.
*
* @param diffListener the listener to which to signal the differences between the inputs and the merged result.
* @param merged the result of merging {@code inputs}.
* @param inputs the inputs whose merge yielded {@code merged}.
*/
public static void diff(RowDiffListener diffListener, Row merged, Row...inputs)
{
Clustering clustering = merged.clustering();
LivenessInfo mergedInfo = merged.primaryKeyLivenessInfo().isEmpty() ? null : merged.primaryKeyLivenessInfo();
Row.Deletion mergedDeletion = merged.deletion().isLive() ? null : merged.deletion();
for (int i = 0; i < inputs.length; i++)
{
Row input = inputs[i];
LivenessInfo inputInfo = input == null || input.primaryKeyLivenessInfo().isEmpty() ? null : input.primaryKeyLivenessInfo();
Row.Deletion inputDeletion = input == null || input.deletion().isLive() ? null : input.deletion();
if (mergedInfo != null || inputInfo != null)
diffListener.onPrimaryKeyLivenessInfo(i, clustering, mergedInfo, inputInfo);
if (mergedDeletion != null || inputDeletion != null)
diffListener.onDeletion(i, clustering, mergedDeletion, inputDeletion);
}
List> inputIterators = new ArrayList<>(1 + inputs.length);
inputIterators.add(merged.iterator());
for (Row row : inputs)
inputIterators.add(row == null ? Collections.emptyIterator() : row.iterator());
Iterator iter = MergeIterator.get(inputIterators, ColumnData.comparator, new MergeIterator.Reducer()
{
ColumnData mergedData;
ColumnData[] inputDatas = new ColumnData[inputs.length];
public void reduce(int idx, ColumnData current)
{
if (idx == 0)
mergedData = current;
else
inputDatas[idx - 1] = current;
}
protected Object getReduced()
{
for (int i = 0 ; i != inputDatas.length ; i++)
{
ColumnData input = inputDatas[i];
if (mergedData != null || input != null)
{
ColumnDefinition column = (mergedData != null ? mergedData : input).column;
if (column.isSimple())
{
diffListener.onCell(i, clustering, (Cell) mergedData, (Cell) input);
}
else
{
ComplexColumnData mergedData = (ComplexColumnData) this.mergedData;
ComplexColumnData inputData = (ComplexColumnData) input;
if (mergedData == null)
{
// Everything in inputData has been shadowed
if (!inputData.complexDeletion().isLive())
diffListener.onComplexDeletion(i, clustering, column, null, inputData.complexDeletion());
for (Cell inputCell : inputData)
diffListener.onCell(i, clustering, null, inputCell);
}
else if (inputData == null)
{
// Everything in inputData is new
if (!mergedData.complexDeletion().isLive())
diffListener.onComplexDeletion(i, clustering, column, mergedData.complexDeletion(), null);
for (Cell mergedCell : mergedData)
diffListener.onCell(i, clustering, mergedCell, null);
}
else
{
if (!mergedData.complexDeletion().isLive() || !inputData.complexDeletion().isLive())
diffListener.onComplexDeletion(i, clustering, column, mergedData.complexDeletion(), inputData.complexDeletion());
PeekingIterator mergedCells = Iterators.peekingIterator(mergedData.iterator());
PeekingIterator| inputCells = Iterators.peekingIterator(inputData.iterator());
while (mergedCells.hasNext() && inputCells.hasNext())
{
int cmp = column.cellPathComparator().compare(mergedCells.peek().path(), inputCells.peek().path());
if (cmp == 0)
diffListener.onCell(i, clustering, mergedCells.next(), inputCells.next());
else if (cmp < 0)
diffListener.onCell(i, clustering, mergedCells.next(), null);
else // cmp > 0
diffListener.onCell(i, clustering, null, inputCells.next());
}
while (mergedCells.hasNext())
diffListener.onCell(i, clustering, mergedCells.next(), null);
while (inputCells.hasNext())
diffListener.onCell(i, clustering, null, inputCells.next());
}
}
}
}
return null;
}
protected void onKeyChange()
{
mergedData = null;
Arrays.fill(inputDatas, null);
}
});
while (iter.hasNext())
iter.next();
}
public static Row merge(Row row1, Row row2, int nowInSec)
{
Row.Builder builder = BTreeRow.sortedBuilder();
merge(row1, row2, builder, nowInSec);
return builder.build();
}
/**
* Merges two rows into the given builder, mainly for merging memtable rows. In addition to reconciling the cells
* in each row, the liveness info, and deletion times for the row and complex columns are also merged.
*
* Note that this method assumes that the provided rows can meaningfully be reconciled together. That is,
* that the rows share the same clustering value, and belong to the same partition.
*
* @param existing
* @param update
* @param builder the row build to which the result of the reconciliation is written.
* @param nowInSec the current time in seconds (which plays a role during reconciliation
* because deleted cells always have precedence on timestamp equality and deciding if a
* cell is a live or not depends on the current time due to expiring cells).
*
* @return the smallest timestamp delta between corresponding rows from existing and update. A
* timestamp delta being computed as the difference between the cells and DeletionTimes from {@code existing}
* and those in {@code existing}.
*/
public static long merge(Row existing,
Row update,
Row.Builder builder,
int nowInSec)
{
Clustering clustering = existing.clustering();
builder.newRow(clustering);
LivenessInfo existingInfo = existing.primaryKeyLivenessInfo();
LivenessInfo updateInfo = update.primaryKeyLivenessInfo();
LivenessInfo mergedInfo = existingInfo.supersedes(updateInfo) ? existingInfo : updateInfo;
long timeDelta = Math.abs(existingInfo.timestamp() - mergedInfo.timestamp());
Row.Deletion rowDeletion = existing.deletion().supersedes(update.deletion()) ? existing.deletion() : update.deletion();
if (rowDeletion.deletes(mergedInfo))
mergedInfo = LivenessInfo.EMPTY;
else if (rowDeletion.isShadowedBy(mergedInfo))
rowDeletion = Row.Deletion.LIVE;
builder.addPrimaryKeyLivenessInfo(mergedInfo);
builder.addRowDeletion(rowDeletion);
DeletionTime deletion = rowDeletion.time();
Iterator a = existing.iterator();
Iterator b = update.iterator();
ColumnData nexta = a.hasNext() ? a.next() : null, nextb = b.hasNext() ? b.next() : null;
while (nexta != null | nextb != null)
{
int comparison = nexta == null ? 1 : nextb == null ? -1 : nexta.column.compareTo(nextb.column);
ColumnData cura = comparison <= 0 ? nexta : null;
ColumnData curb = comparison >= 0 ? nextb : null;
ColumnDefinition column = getColumnDefinition(cura, curb);
if (column.isSimple())
{
timeDelta = Math.min(timeDelta, Cells.reconcile((Cell) cura, (Cell) curb, deletion, builder, nowInSec));
}
else
{
ComplexColumnData existingData = (ComplexColumnData) cura;
ComplexColumnData updateData = (ComplexColumnData) curb;
DeletionTime existingDt = existingData == null ? DeletionTime.LIVE : existingData.complexDeletion();
DeletionTime updateDt = updateData == null ? DeletionTime.LIVE : updateData.complexDeletion();
DeletionTime maxDt = existingDt.supersedes(updateDt) ? existingDt : updateDt;
if (maxDt.supersedes(deletion))
builder.addComplexDeletion(column, maxDt);
else
maxDt = deletion;
Iterator existingCells = existingData == null ? null : existingData.iterator();
Iterator| updateCells = updateData == null ? null : updateData.iterator();
timeDelta = Math.min(timeDelta, Cells.reconcileComplex(column, existingCells, updateCells, maxDt, builder, nowInSec));
}
if (cura != null)
nexta = a.hasNext() ? a.next() : null;
if (curb != null)
nextb = b.hasNext() ? b.next() : null;
}
return timeDelta;
}
/**
* Returns the {@code ColumnDefinition} to use for merging the columns.
* If the 2 column definitions are different the latest one will be returned.
*/
private static ColumnDefinition getColumnDefinition(ColumnData cura, ColumnData curb)
{
if (cura == null)
return curb.column;
if (curb == null)
return cura.column;
if (AbstractTypeVersionComparator.INSTANCE.compare(cura.column.type, curb.column.type) >= 0)
return cura.column;
return curb.column;
}
}
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