/*
* 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;
import java.util.AbstractCollection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.collect.Iterators;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.db.composites.CellName;
import org.apache.cassandra.db.composites.Composite;
import org.apache.cassandra.db.filter.ColumnSlice;
import org.apache.cassandra.db.index.SecondaryIndexManager;
import org.apache.cassandra.utils.ObjectSizes;
import org.apache.cassandra.utils.btree.BTree;
import org.apache.cassandra.utils.btree.BTreeSet;
import org.apache.cassandra.utils.btree.UpdateFunction;
import org.apache.cassandra.utils.concurrent.OpOrder;
import org.apache.cassandra.utils.memory.MemtableAllocator;
import static org.apache.cassandra.db.index.SecondaryIndexManager.Updater;
/**
* A thread-safe and atomic ISortedColumns implementation.
* Operations (in particular addAll) on this implemenation are atomic and
* isolated (in the sense of ACID). Typically a addAll is guaranteed that no
* other thread can see the state where only parts but not all columns have
* been added.
* <p/>
* WARNING: removing element through getSortedColumns().iterator() is *not* supported
*/
public class AtomicBTreeColumns extends ColumnFamily
{
static final long EMPTY_SIZE = ObjectSizes.measure(new AtomicBTreeColumns(CFMetaData.IndexCf, null))
+ ObjectSizes.measure(new Holder(null, null));
private static final Function<Cell, CellName> NAME = new Function<Cell, CellName>()
{
public CellName apply(Cell column)
{
return column.name();
}
};
public static final Factory<AtomicBTreeColumns> factory = new Factory<AtomicBTreeColumns>()
{
public AtomicBTreeColumns create(CFMetaData metadata, boolean insertReversed, int initialCapacity)
{
if (insertReversed)
throw new IllegalArgumentException();
return new AtomicBTreeColumns(metadata);
}
};
private static final DeletionInfo LIVE = DeletionInfo.live();
// This is a small optimization: DeletionInfo is mutable, but we know that we will always copy it in that class,
// so we can safely alias one DeletionInfo.live() reference and avoid some allocations.
private static final Holder EMPTY = new Holder(BTree.empty(), LIVE);
private volatile Holder ref;
private static final AtomicReferenceFieldUpdater<AtomicBTreeColumns, Holder> refUpdater = AtomicReferenceFieldUpdater.newUpdater(AtomicBTreeColumns.class, Holder.class, "ref");
private AtomicBTreeColumns(CFMetaData metadata)
{
this(metadata, EMPTY);
}
private AtomicBTreeColumns(CFMetaData metadata, Holder holder)
{
super(metadata);
this.ref = holder;
}
public Factory getFactory()
{
return factory;
}
public ColumnFamily cloneMe()
{
return new AtomicBTreeColumns(metadata, ref);
}
public DeletionInfo deletionInfo()
{
return ref.deletionInfo;
}
public void delete(DeletionTime delTime)
{
delete(new DeletionInfo(delTime));
}
protected void delete(RangeTombstone tombstone)
{
delete(new DeletionInfo(tombstone, getComparator()));
}
public void delete(DeletionInfo info)
{
if (info.isLive())
return;
// Keeping deletion info for max markedForDeleteAt value
while (true)
{
Holder current = ref;
DeletionInfo curDelInfo = current.deletionInfo;
DeletionInfo newDelInfo = info.mayModify(curDelInfo) ? curDelInfo.copy().add(info) : curDelInfo;
if (refUpdater.compareAndSet(this, current, current.with(newDelInfo)))
break;
}
}
public void setDeletionInfo(DeletionInfo newInfo)
{
ref = ref.with(newInfo);
}
public void purgeTombstones(int gcBefore)
{
while (true)
{
Holder current = ref;
if (!current.deletionInfo.hasPurgeableTombstones(gcBefore))
break;
DeletionInfo purgedInfo = current.deletionInfo.copy();
purgedInfo.purge(gcBefore);
if (refUpdater.compareAndSet(this, current, current.with(purgedInfo)))
break;
}
}
/**
* This is only called by Memtable.resolve, so only AtomicBTreeColumns needs to implement it.
*
* @return the difference in size seen after merging the given columns
*/
public long addAllWithSizeDelta(final ColumnFamily cm, MemtableAllocator allocator, OpOrder.Group writeOp, Updater indexer)
{
ColumnUpdater updater = new ColumnUpdater(this, cm.metadata, allocator, writeOp, indexer);
while (true)
{
Holder current = ref;
updater.ref = current;
updater.reset();
DeletionInfo deletionInfo;
if (cm.deletionInfo().mayModify(current.deletionInfo))
{
deletionInfo = current.deletionInfo.copy().add(cm.deletionInfo());
updater.allocated(deletionInfo.unsharedHeapSize() - current.deletionInfo.unsharedHeapSize());
}
else
{
deletionInfo = current.deletionInfo;
}
Object[] tree = BTree.update(current.tree, metadata.comparator.columnComparator(), cm, cm.getColumnCount(), true, updater);
if (tree != null && refUpdater.compareAndSet(this, current, new Holder(tree, deletionInfo)))
{
indexer.updateRowLevelIndexes();
updater.finish();
return updater.dataSize;
}
}
}
// no particular reason not to implement these next methods, we just haven't needed them yet
public void addColumn(Cell column)
{
throw new UnsupportedOperationException();
}
public void addAll(ColumnFamily cf)
{
throw new UnsupportedOperationException();
}
public void clear()
{
throw new UnsupportedOperationException();
}
public Cell getColumn(CellName name)
{
return (Cell) BTree.find(ref.tree, asymmetricComparator(), name);
}
private Comparator<Object> asymmetricComparator()
{
final Comparator<? super CellName> cmp = metadata.comparator;
return new Comparator<Object>()
{
public int compare(Object o1, Object o2)
{
return cmp.compare((CellName) o1, ((Cell) o2).name());
}
};
}
public Iterable<CellName> getColumnNames()
{
return collection(false, NAME);
}
public Collection<Cell> getSortedColumns()
{
return collection(true, Functions.<Cell>identity());
}
public Collection<Cell> getReverseSortedColumns()
{
return collection(false, Functions.<Cell>identity());
}
private <V> Collection<V> collection(final boolean forwards, final Function<Cell, V> f)
{
final Holder ref = this.ref;
return new AbstractCollection<V>()
{
public Iterator<V> iterator()
{
return Iterators.transform(BTree.<Cell>slice(ref.tree, forwards), f);
}
public int size()
{
return BTree.slice(ref.tree, true).count();
}
};
}
public int getColumnCount()
{
return BTree.slice(ref.tree, true).count();
}
public boolean hasColumns()
{
return !BTree.isEmpty(ref.tree);
}
public Iterator<Cell> iterator(ColumnSlice[] slices)
{
return new ColumnSlice.NavigableSetIterator(new BTreeSet<>(ref.tree, getComparator().columnComparator()), slices);
}
public Iterator<Cell> reverseIterator(ColumnSlice[] slices)
{
return new ColumnSlice.NavigableSetIterator(new BTreeSet<>(ref.tree, getComparator().columnComparator()).descendingSet(), slices);
}
public boolean isInsertReversed()
{
return false;
}
private static final class Holder
{
final DeletionInfo deletionInfo;
// the btree of columns
final Object[] tree;
Holder(Object[] tree, DeletionInfo deletionInfo)
{
this.tree = tree;
this.deletionInfo = deletionInfo;
}
Holder with(DeletionInfo info)
{
return new Holder(this.tree, info);
}
private Iterator<Cell> cellRange(Comparator<Cell> comparator, Composite start, Composite finish)
{
return new ColumnSlice.NavigableSetIterator(new BTreeSet<>(tree, comparator), new ColumnSlice[]{ new ColumnSlice(start, finish) });
}
}
// the function we provide to the btree utilities to perform any column replacements
private static final class ColumnUpdater implements UpdateFunction<Cell>
{
final AtomicBTreeColumns updating;
final CFMetaData metadata;
final MemtableAllocator allocator;
final OpOrder.Group writeOp;
final Updater indexer;
Holder ref;
long dataSize;
long heapSize;
final MemtableAllocator.DataReclaimer reclaimer;
List<Cell> inserted; // TODO: replace with walk of aborted BTree
private ColumnUpdater(AtomicBTreeColumns updating, CFMetaData metadata, MemtableAllocator allocator, OpOrder.Group writeOp, Updater indexer)
{
this.updating = updating;
this.allocator = allocator;
this.writeOp = writeOp;
this.indexer = indexer;
this.metadata = metadata;
this.reclaimer = allocator.reclaimer();
}
public Cell apply(Cell insert)
{
indexer.insert(insert);
insert = insert.localCopy(metadata, allocator, writeOp);
this.dataSize += insert.cellDataSize();
this.heapSize += insert.excessHeapSizeExcludingData();
if (inserted == null)
inserted = new ArrayList<>();
inserted.add(insert);
return insert;
}
public Cell apply(Cell existing, Cell update)
{
Cell reconciled = existing.reconcile(update);
indexer.update(existing, reconciled);
if (existing != reconciled)
{
reconciled = reconciled.localCopy(metadata, allocator, writeOp);
dataSize += reconciled.cellDataSize() - existing.cellDataSize();
heapSize += reconciled.excessHeapSizeExcludingData() - existing.excessHeapSizeExcludingData();
if (inserted == null)
inserted = new ArrayList<>();
inserted.add(reconciled);
discard(existing);
}
return reconciled;
}
protected void reset()
{
this.dataSize = 0;
this.heapSize = 0;
if (inserted != null)
{
for (Cell cell : inserted)
abort(cell);
inserted.clear();
}
reclaimer.cancel();
}
protected void abort(Cell abort)
{
reclaimer.reclaimImmediately(abort);
}
protected void discard(Cell discard)
{
reclaimer.reclaim(discard);
}
public boolean abortEarly()
{
return updating.ref != ref;
}
public void allocated(long heapSize)
{
this.heapSize += heapSize;
}
protected void finish()
{
allocator.onHeap().allocate(heapSize, writeOp);
reclaimer.commit();
}
}
}