Rows.java
/*
* 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.schema.ColumnMetadata;
import org.apache.cassandra.schema.TableMetadata;
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);
/**
* Creates a new simple row builder.
*
* @param metadata the metadata of the table this is a row of.
* @param clusteringValues the value for the clustering columns of the row to add to this build. There may be no
* values if either the table has no clustering column, or if you want to edit the static row. Note that as a
* shortcut it is also allowed to pass a {@code Clustering} object directly, in which case that should be the
* only argument.
* @return a newly created builder.
*/
public static Row.SimpleBuilder simpleBuilder(TableMetadata metadata, Object... clusteringValues)
{
return new SimpleBuilders.RowBuilder(metadata, clusteringValues);
}
private static class StatsAccumulation
{
private static final long COLUMN_INCR = 1L << 32;
private static final long CELL_INCR = 1L;
private static long accumulateOnCell(PartitionStatisticsCollector collector, Cell<?> cell, long l)
{
Cells.collectStats(cell, collector);
return l + CELL_INCR;
}
private static long accumulateOnColumnData(PartitionStatisticsCollector collector, ColumnData cd, long l)
{
if (cd.column().isSimple())
{
l = accumulateOnCell(collector, (Cell<?>) cd, l) + COLUMN_INCR;
}
else
{
ComplexColumnData complexData = (ComplexColumnData)cd;
collector.update(complexData.complexDeletion());
int startingCells = unpackCellCount(l);
l = complexData.accumulate(StatsAccumulation::accumulateOnCell, collector, l);
if (unpackCellCount(l) > startingCells)
l += COLUMN_INCR;
}
return l;
}
private static int unpackCellCount(long v)
{
return (int) (v & 0xFFFFFFFFL);
}
private static int unpackColumnCount(long v)
{
return (int) (v >>> 32);
}
}
/**
* 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());
long result = row.accumulate(StatsAccumulation::accumulateOnColumnData, collector, 0);
collector.updateColumnSetPerRow(StatsAccumulation.unpackColumnCount(result));
return StatsAccumulation.unpackCellCount(result);
}
/**
* Given the result ({@code merged}) of merging multiple {@code inputs}, signals the difference between
* each input and {@code merged} to {@code diffListener}.
* <p>
* 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}.
*/
@SuppressWarnings("resource")
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<Iterator<ColumnData>> 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, Object>()
{
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)
{
ColumnMetadata 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<Cell<?>> mergedCells = Iterators.peekingIterator(mergedData.iterator());
PeekingIterator<Cell<?>> 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 existing, Row update)
{
return merge(existing, update, ColumnData.noOp);
}
/**
* Merges two 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.
* <p>
* 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
*
* @return the row resulting from the merge.
*/
public static Row merge(Row existing, Row update, ColumnData.PostReconciliationFunction onReconcile)
{
assert existing instanceof BTreeRow;
assert update instanceof BTreeRow;
return BTreeRow.merge((BTreeRow) existing, (BTreeRow) update, onReconcile);
}
/**
* Returns a row that is obtained from the given existing row by removing everything that is shadowed by data in
* the update row. In other words, produces the smallest result row such that
* {@code merge(result, update, nowInSec) == merge(existing, update, nowInSec)} after filtering by rangeDeletion.
*
* @param existing source row
* @param update shadowing row
* @param rangeDeletion extra {@code DeletionTime} from covering tombstone
*/
public static Row removeShadowedCells(Row existing, Row update, DeletionTime rangeDeletion)
{
Row.Builder builder = BTreeRow.sortedBuilder();
Clustering<?> clustering = existing.clustering();
builder.newRow(clustering);
DeletionTime deletion = update.deletion().time();
if (rangeDeletion.supersedes(deletion))
deletion = rangeDeletion;
LivenessInfo existingInfo = existing.primaryKeyLivenessInfo();
if (!deletion.deletes(existingInfo))
builder.addPrimaryKeyLivenessInfo(existingInfo);
Row.Deletion rowDeletion = existing.deletion();
if (!deletion.supersedes(rowDeletion.time()))
builder.addRowDeletion(rowDeletion);
Iterator<ColumnData> a = existing.iterator();
Iterator<ColumnData> b = update.iterator();
ColumnData nexta = a.hasNext() ? a.next() : null, nextb = b.hasNext() ? b.next() : null;
while (nexta != null)
{
int comparison = nextb == null ? -1 : nexta.column.compareTo(nextb.column);
if (comparison <= 0)
{
ColumnData cura = nexta;
ColumnMetadata column = cura.column;
ColumnData curb = comparison == 0 ? nextb : null;
if (column.isSimple())
{
Cells.addNonShadowed((Cell<?>) cura, (Cell<?>) curb, deletion, builder);
}
else
{
ComplexColumnData existingData = (ComplexColumnData) cura;
ComplexColumnData updateData = (ComplexColumnData) curb;
DeletionTime existingDt = existingData.complexDeletion();
DeletionTime updateDt = updateData == null ? DeletionTime.LIVE : updateData.complexDeletion();
DeletionTime maxDt = updateDt.supersedes(deletion) ? updateDt : deletion;
if (existingDt.supersedes(maxDt))
{
builder.addComplexDeletion(column, existingDt);
maxDt = existingDt;
}
Iterator<Cell<?>> existingCells = existingData.iterator();
Iterator<Cell<?>> updateCells = updateData == null ? null : updateData.iterator();
Cells.addNonShadowedComplex(column, existingCells, updateCells, maxDt, builder);
}
nexta = a.hasNext() ? a.next() : null;
if (curb != null)
nextb = b.hasNext() ? b.next() : null;
}
else
{
nextb = b.hasNext() ? b.next() : null;
}
}
Row row = builder.build();
return row != null && !row.isEmpty() ? row : null;
}
}