/*
* 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.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import com.google.common.collect.AbstractIterator;
import org.apache.cassandra.db.composites.CType;
import org.apache.cassandra.db.composites.Composite;
import org.apache.cassandra.io.IVersionedSerializer;
import org.apache.cassandra.net.MessagingService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Data structure holding the range tombstones of a ColumnFamily.
* <p>
* This is essentially a sorted list of non-overlapping (tombstone) ranges.
* <p>
* A range tombstone has 4 elements: the start and end of the range covered,
* and the deletion infos (markedAt timestamp and local deletion time). The
* markedAt timestamp is what define the priority of 2 overlapping tombstones.
* That is, given 2 tombstones [0, 10]@t1 and [5, 15]@t2, then if t2 > t1 (and
* are the tombstones markedAt values), the 2nd tombstone take precedence over
* the first one on [5, 10]. If such tombstones are added to a RangeTombstoneList,
* the range tombstone list will store them as [[0, 5]@t1, [5, 15]@t2].
* <p>
* The only use of the local deletion time is to know when a given tombstone can
* be purged, which will be done by the purge() method.
*/
public class RangeTombstoneList implements Iterable<RangeTombstone>
{
private static final Logger logger = LoggerFactory.getLogger(RangeTombstoneList.class);
private final Comparator<Composite> comparator;
// Note: we don't want to use a List for the markedAts and delTimes to avoid boxing. We could
// use a List for starts and ends, but having arrays everywhere is almost simpler.
private Composite[] starts;
private Composite[] ends;
private long[] markedAts;
private int[] delTimes;
private int size;
private RangeTombstoneList(Comparator<Composite> comparator, Composite[] starts, Composite[] ends, long[] markedAts, int[] delTimes, int size)
{
assert starts.length == ends.length && starts.length == markedAts.length && starts.length == delTimes.length;
this.comparator = comparator;
this.starts = starts;
this.ends = ends;
this.markedAts = markedAts;
this.delTimes = delTimes;
this.size = size;
}
public RangeTombstoneList(Comparator<Composite> comparator, int capacity)
{
this(comparator, new Composite[capacity], new Composite[capacity], new long[capacity], new int[capacity], 0);
}
public boolean isEmpty()
{
return size == 0;
}
public int size()
{
return size;
}
public Comparator<Composite> comparator()
{
return comparator;
}
public RangeTombstoneList copy()
{
return new RangeTombstoneList(comparator,
Arrays.copyOf(starts, size),
Arrays.copyOf(ends, size),
Arrays.copyOf(markedAts, size),
Arrays.copyOf(delTimes, size),
size);
}
public void add(RangeTombstone tombstone)
{
add(tombstone.min, tombstone.max, tombstone.data.markedForDeleteAt, tombstone.data.localDeletionTime);
}
/**
* Adds a new range tombstone.
*
* This method will be faster if the new tombstone sort after all the currently existing ones (this is a common use case),
* but it doesn't assume it.
*/
public void add(Composite start, Composite end, long markedAt, int delTime)
{
if (isEmpty())
{
addInternal(0, start, end, markedAt, delTime);
return;
}
int c = comparator.compare(ends[size-1], start);
// Fast path if we add in sorted order
if (c <= 0)
{
addInternal(size, start, end, markedAt, delTime);
}
else
{
// Note: insertFrom expect i to be the insertion point in term of interval ends
int pos = Arrays.binarySearch(ends, 0, size, start, comparator);
insertFrom((pos >= 0 ? pos+1 : -pos-1), start, end, markedAt, delTime);
}
}
/**
* Adds all the range tombstones of {@code tombstones} to this RangeTombstoneList.
*/
public void addAll(RangeTombstoneList tombstones)
{
if (tombstones.isEmpty())
return;
if (isEmpty())
{
copyArrays(tombstones, this);
return;
}
/*
* We basically have 2 techniques we can use here: either we repeatedly call add() on tombstones values,
* or we do a merge of both (sorted) lists. If this lists is bigger enough than the one we add, then
* calling add() will be faster, otherwise it's merging that will be faster.
*
* Let's note that during memtables updates, it might not be uncommon that a new update has only a few range
* tombstones, while the CF we're adding it to (the one in the memtable) has many. In that case, using add() is
* likely going to be faster.
*
* In other cases however, like when diffing responses from multiple nodes, the tombstone lists we "merge" will
* be likely sized, so using add() might be a bit inefficient.
*
* Roughly speaking (this ignore the fact that updating an element is not exactly constant but that's not a big
* deal), if n is the size of this list and m is tombstones size, merging is O(n+m) while using add() is O(m*log(n)).
*
* But let's not crank up a logarithm computation for that. Long story short, merging will be a bad choice only
* if this list size is lot bigger that the other one, so let's keep it simple.
*/
if (size > 10 * tombstones.size)
{
for (int i = 0; i < tombstones.size; i++)
add(tombstones.starts[i], tombstones.ends[i], tombstones.markedAts[i], tombstones.delTimes[i]);
}
else
{
int i = 0;
int j = 0;
while (i < size && j < tombstones.size)
{
if (comparator.compare(tombstones.starts[j], ends[i]) < 0)
{
insertFrom(i, tombstones.starts[j], tombstones.ends[j], tombstones.markedAts[j], tombstones.delTimes[j]);
j++;
}
else
{
i++;
}
}
// Addds the remaining ones from tombstones if any (note that addInternal will increment size if relevant).
for (; j < tombstones.size; j++)
addInternal(size, tombstones.starts[j], tombstones.ends[j], tombstones.markedAts[j], tombstones.delTimes[j]);
}
}
/**
* Returns whether the given name/timestamp pair is deleted by one of the tombstone
* of this RangeTombstoneList.
*/
public boolean isDeleted(Composite name, long timestamp)
{
int idx = searchInternal(name);
return idx >= 0 && markedAts[idx] >= timestamp;
}
/**
* Returns a new {@link InOrderTester}.
*/
InOrderTester inOrderTester()
{
return new InOrderTester();
}
/**
* Returns the DeletionTime for the tombstone overlapping {@code name} (there can't be more than one),
* or null if {@code name} is not covered by any tombstone.
*/
public DeletionTime search(Composite name) {
int idx = searchInternal(name);
return idx < 0 ? null : new DeletionTime(markedAts[idx], delTimes[idx]);
}
private int searchInternal(Composite name)
{
if (isEmpty())
return -1;
int pos = Arrays.binarySearch(starts, 0, size, name, comparator);
if (pos >= 0)
{
// We're exactly on an interval start. The one subtility is that we need to check if
// the previous is not equal to us and doesn't have a higher marked at
if (pos > 0 && comparator.compare(name, ends[pos-1]) == 0 && markedAts[pos-1] > markedAts[pos])
return pos-1;
else
return pos;
}
else
{
// We potentially intersect the range before our "insertion point"
int idx = -pos-2;
if (idx < 0)
return -1;
return comparator.compare(name, ends[idx]) <= 0 ? idx : -1;
}
}
public int dataSize()
{
int dataSize = TypeSizes.NATIVE.sizeof(size);
for (int i = 0; i < size; i++)
{
dataSize += starts[i].dataSize() + ends[i].dataSize();
dataSize += TypeSizes.NATIVE.sizeof(markedAts[i]);
dataSize += TypeSizes.NATIVE.sizeof(delTimes[i]);
}
return dataSize;
}
public long minMarkedAt()
{
long min = Long.MAX_VALUE;
for (int i = 0; i < size; i++)
min = Math.min(min, markedAts[i]);
return min;
}
public long maxMarkedAt()
{
long max = Long.MIN_VALUE;
for (int i = 0; i < size; i++)
max = Math.max(max, markedAts[i]);
return max;
}
public void updateAllTimestamp(long timestamp)
{
for (int i = 0; i < size; i++)
markedAts[i] = timestamp;
}
/**
* Removes all range tombstones whose local deletion time is older than gcBefore.
*/
public void purge(int gcBefore)
{
int j = 0;
for (int i = 0; i < size; i++)
{
if (delTimes[i] >= gcBefore)
setInternal(j++, starts[i], ends[i], markedAts[i], delTimes[i]);
}
size = j;
}
/**
* Returns whether {@code purge(gcBefore)} would remove something or not.
*/
public boolean hasPurgeableTombstones(int gcBefore)
{
for (int i = 0; i < size; i++)
{
if (delTimes[i] < gcBefore)
return true;
}
return false;
}
public Iterator<RangeTombstone> iterator()
{
return new AbstractIterator<RangeTombstone>()
{
private int idx;
protected RangeTombstone computeNext()
{
if (idx >= size)
return endOfData();
RangeTombstone t = new RangeTombstone(starts[idx], ends[idx], markedAts[idx], delTimes[idx]);
idx++;
return t;
}
};
}
@Override
public boolean equals(Object o)
{
if(!(o instanceof RangeTombstoneList))
return false;
RangeTombstoneList that = (RangeTombstoneList)o;
if (size != that.size)
return false;
for (int i = 0; i < size; i++)
{
if (!starts[i].equals(that.starts[i]))
return false;
if (!ends[i].equals(that.ends[i]))
return false;
if (markedAts[i] != that.markedAts[i])
return false;
if (delTimes[i] != that.delTimes[i])
return false;
}
return true;
}
@Override
public final int hashCode()
{
int result = size;
for (int i = 0; i < size; i++)
{
result += starts[i].hashCode() + ends[i].hashCode();
result += (int)(markedAts[i] ^ (markedAts[i] >>> 32));
result += delTimes[i];
}
return result;
}
private static void copyArrays(RangeTombstoneList src, RangeTombstoneList dst)
{
dst.grow(src.size);
System.arraycopy(src.starts, 0, dst.starts, 0, src.size);
System.arraycopy(src.ends, 0, dst.ends, 0, src.size);
System.arraycopy(src.markedAts, 0, dst.markedAts, 0, src.size);
System.arraycopy(src.delTimes, 0, dst.delTimes, 0, src.size);
dst.size = src.size;
}
/*
* Inserts a new element starting at index i. This method assumes that i is the insertion point
* in term of intervals for start:
* ends[i-1] <= start < ends[i]
*/
private void insertFrom(int i, Composite start, Composite end, long markedAt, int delTime)
{
while (i < size)
{
assert i == 0 || comparator.compare(start, ends[i-1]) >= 0;
assert i >= size || comparator.compare(start, ends[i]) < 0;
// Do we overwrite the current element?
if (markedAt > markedAts[i])
{
// We do overwrite.
// First deal with what might come before the newly added one.
if (comparator.compare(starts[i], start) < 0)
{
addInternal(i, starts[i], start, markedAts[i], delTimes[i]);
i++;
// We don't need to do the following line, but in spirit that's what we want to do
// setInternal(i, start, ends[i], markedAts, delTime])
}
// now, start <= starts[i]
// If the new element stops before the current one, insert it and
// we're done
if (comparator.compare(end, starts[i]) <= 0)
{
addInternal(i, start, end, markedAt, delTime);
return;
}
// Do we overwrite the current element fully?
int cmp = comparator.compare(ends[i], end);
if (cmp <= 0)
{
// We do overwrite fully:
// update the current element until it's end and continue
// on with the next element (with the new inserted start == current end).
// If we're on the last element, we can optimize
if (i == size-1)
{
setInternal(i, start, end, markedAt, delTime);
return;
}
setInternal(i, start, ends[i], markedAt, delTime);
if (cmp == 0)
return;
start = ends[i];
i++;
}
else
{
// We don't ovewrite fully. Insert the new interval, and then update the now next
// one to reflect the not overwritten parts. We're then done.
addInternal(i, start, end, markedAt, delTime);
i++;
setInternal(i, end, ends[i], markedAts[i], delTimes[i]);
return;
}
}
else
{
// we don't overwrite the current element
// If the new interval starts before the current one, insert that new interval
if (comparator.compare(start, starts[i]) < 0)
{
// If we stop before the start of the current element, just insert the new
// interval and we're done; otherwise insert until the beginning of the
// current element
if (comparator.compare(end, starts[i]) <= 0)
{
addInternal(i, start, end, markedAt, delTime);
return;
}
addInternal(i, start, starts[i], markedAt, delTime);
i++;
}
// After that, we're overwritten on the current element but might have
// some residual parts after ...
// ... unless we don't extend beyond it.
if (comparator.compare(end, ends[i]) <= 0)
return;
start = ends[i];
i++;
}
}
// If we got there, then just insert the remainder at the end
addInternal(i, start, end, markedAt, delTime);
}
private int capacity()
{
return starts.length;
}
/*
* Adds the new tombstone at index i, growing and/or moving elements to make room for it.
*/
private void addInternal(int i, Composite start, Composite end, long markedAt, int delTime)
{
assert i >= 0;
if (size == capacity())
growToFree(i);
else if (i < size)
moveElements(i);
setInternal(i, start, end, markedAt, delTime);
size++;
}
/*
* Grow the arrays, leaving index i "free" in the process.
*/
private void growToFree(int i)
{
int newLength = (capacity() * 3) / 2 + 1;
grow(i, newLength);
}
/*
* Grow the arrays to match newLength capacity.
*/
private void grow(int newLength)
{
if (capacity() < newLength)
grow(-1, newLength);
}
private void grow(int i, int newLength)
{
starts = grow(starts, size, newLength, i);
ends = grow(ends, size, newLength, i);
markedAts = grow(markedAts, size, newLength, i);
delTimes = grow(delTimes, size, newLength, i);
}
private static Composite[] grow(Composite[] a, int size, int newLength, int i)
{
if (i < 0 || i >= size)
return Arrays.copyOf(a, newLength);
Composite[] newA = new Composite[newLength];
System.arraycopy(a, 0, newA, 0, i);
System.arraycopy(a, i, newA, i+1, size - i);
return newA;
}
private static long[] grow(long[] a, int size, int newLength, int i)
{
if (i < 0 || i >= size)
return Arrays.copyOf(a, newLength);
long[] newA = new long[newLength];
System.arraycopy(a, 0, newA, 0, i);
System.arraycopy(a, i, newA, i+1, size - i);
return newA;
}
private static int[] grow(int[] a, int size, int newLength, int i)
{
if (i < 0 || i >= size)
return Arrays.copyOf(a, newLength);
int[] newA = new int[newLength];
System.arraycopy(a, 0, newA, 0, i);
System.arraycopy(a, i, newA, i+1, size - i);
return newA;
}
/*
* Move elements so that index i is "free", assuming the arrays have at least one free slot at the end.
*/
private void moveElements(int i)
{
if (i >= size)
return;
System.arraycopy(starts, i, starts, i+1, size - i);
System.arraycopy(ends, i, ends, i+1, size - i);
System.arraycopy(markedAts, i, markedAts, i+1, size - i);
System.arraycopy(delTimes, i, delTimes, i+1, size - i);
}
private void setInternal(int i, Composite start, Composite end, long markedAt, int delTime)
{
starts[i] = start;
ends[i] = end;
markedAts[i] = markedAt;
delTimes[i] = delTime;
}
public static class Serializer implements IVersionedSerializer<RangeTombstoneList>
{
private final CType type;
public Serializer(CType type)
{
this.type = type;
}
public void serialize(RangeTombstoneList tombstones, DataOutput out, int version) throws IOException
{
if (tombstones == null)
{
out.writeInt(0);
return;
}
out.writeInt(tombstones.size);
for (int i = 0; i < tombstones.size; i++)
{
type.serializer().serialize(tombstones.starts[i], out);
type.serializer().serialize(tombstones.ends[i], out);
out.writeInt(tombstones.delTimes[i]);
out.writeLong(tombstones.markedAts[i]);
}
}
public RangeTombstoneList deserialize(DataInput in, int version) throws IOException
{
int size = in.readInt();
if (size == 0)
return null;
RangeTombstoneList tombstones = new RangeTombstoneList(type, size);
for (int i = 0; i < size; i++)
{
Composite start = type.serializer().deserialize(in);
Composite end = type.serializer().deserialize(in);
int delTime = in.readInt();
long markedAt = in.readLong();
if (version >= MessagingService.VERSION_20)
{
tombstones.setInternal(i, start, end, markedAt, delTime);
}
else
{
/*
* The old implementation used to have range sorted by left value, but with potentially
* overlapping range. So we need to use the "slow" path.
*/
tombstones.add(start, end, markedAt, delTime);
}
}
// The "slow" path take care of updating the size, but not the fast one
if (version >= MessagingService.VERSION_20)
tombstones.size = size;
return tombstones;
}
public long serializedSize(RangeTombstoneList tombstones, TypeSizes typeSizes, int version)
{
if (tombstones == null)
return typeSizes.sizeof(0);
long size = typeSizes.sizeof(tombstones.size);
for (int i = 0; i < tombstones.size; i++)
{
size += type.serializer().serializedSize(tombstones.starts[i], typeSizes);
size += type.serializer().serializedSize(tombstones.ends[i], typeSizes);
size += typeSizes.sizeof(tombstones.delTimes[i]);
size += typeSizes.sizeof(tombstones.markedAts[i]);
}
return size;
}
public long serializedSize(RangeTombstoneList tombstones, int version)
{
return serializedSize(tombstones, TypeSizes.NATIVE, version);
}
}
/**
* This object allow testing whether a given column (name/timestamp) is deleted
* or not by this RangeTombstoneList, assuming that the column given to this
* object are passed in (comparator) sorted order.
*
* This is more efficient that calling RangeTombstoneList.isDeleted() repeatedly
* in that case since we're able to take the sorted nature of the RangeTombstoneList
* into account.
*/
public class InOrderTester
{
private int idx;
public boolean isDeleted(Composite name, long timestamp)
{
while (idx < size)
{
int cmp = comparator.compare(name, starts[idx]);
if (cmp == 0)
{
// As for searchInternal, we need to check the previous end
if (idx > 0 && comparator.compare(name, ends[idx-1]) == 0 && markedAts[idx-1] > markedAts[idx])
return markedAts[idx-1] >= timestamp;
else
return markedAts[idx] >= timestamp;
}
else if (cmp < 0)
{
return false;
}
else
{
if (comparator.compare(name, ends[idx]) <= 0)
return markedAts[idx] >= timestamp;
else
idx++;
}
}
return false;
}
}
}