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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;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.ColumnDefinition;
import org.apache.cassandra.db.filter.*;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.db.marshal.CompositeType;
import org.apache.cassandra.dht.*;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
/**
* Groups both the range of partitions to query, and the clustering index filter to
* apply for each partition (for a (partition) range query).
*
* The main "trick" is that the clustering index filter can only be obtained by
* providing the partition key on which the filter will be applied. This is
* necessary when paging range queries, as we might need a different filter
* for the starting key than for other keys (because the previous page we had
* queried may have ended in the middle of a partition).
*/
public class DataRange
{
public static final Serializer serializer = new Serializer();
protected final AbstractBounds keyRange;
protected final ClusteringIndexFilter clusteringIndexFilter;
/**
* Creates a {@code DataRange} given a range of partition keys and a clustering index filter. The
* return {@code DataRange} will return the same filter for all keys.
*
* @param range the range over partition keys to use.
* @param clusteringIndexFilter the clustering index filter to use.
*/
public DataRange(AbstractBounds range, ClusteringIndexFilter clusteringIndexFilter)
{
this.keyRange = range;
this.clusteringIndexFilter = clusteringIndexFilter;
}
/**
* Creates a {@code DataRange} to query all data (over the whole ring).
*
* @param partitioner the partitioner in use for the table.
*
* @return the newly create {@code DataRange}.
*/
public static DataRange allData(IPartitioner partitioner)
{
return forTokenRange(new Range(partitioner.getMinimumToken(), partitioner.getMinimumToken()));
}
/**
* Creates a {@code DataRange} to query all rows over the provided token range.
*
* @param tokenRange the (partition key) token range to query.
*
* @return the newly create {@code DataRange}.
*/
public static DataRange forTokenRange(Range tokenRange)
{
return forKeyRange(Range.makeRowRange(tokenRange));
}
/**
* Creates a {@code DataRange} to query all rows over the provided key range.
*
* @param keyRange the (partition key) range to query.
*
* @return the newly create {@code DataRange}.
*/
public static DataRange forKeyRange(Range keyRange)
{
return new DataRange(keyRange, new ClusteringIndexSliceFilter(Slices.ALL, false));
}
/**
* Creates a {@code DataRange} to query all partitions of the ring using the provided
* clustering index filter.
*
* @param partitioner the partitioner in use for the table queried.
* @param filter the clustering index filter to use.
*
* @return the newly create {@code DataRange}.
*/
public static DataRange allData(IPartitioner partitioner, ClusteringIndexFilter filter)
{
return new DataRange(Range.makeRowRange(new Range(partitioner.getMinimumToken(), partitioner.getMinimumToken())), filter);
}
/**
* The range of partition key queried by this {@code DataRange}.
*
* @return the range of partition key queried by this {@code DataRange}.
*/
public AbstractBounds keyRange()
{
return keyRange;
}
/**
* The start of the partition key range queried by this {@code DataRange}.
*
* @return the start of the partition key range queried by this {@code DataRange}.
*/
public PartitionPosition startKey()
{
return keyRange.left;
}
/**
* The end of the partition key range queried by this {@code DataRange}.
*
* @return the end of the partition key range queried by this {@code DataRange}.
*/
public PartitionPosition stopKey()
{
return keyRange.right;
}
/**
* Whether the underlying clustering index filter is a names filter or not.
*
* @return Whether the underlying clustering index filter is a names filter or not.
*/
public boolean isNamesQuery()
{
return clusteringIndexFilter instanceof ClusteringIndexNamesFilter;
}
/**
* Whether the data range is for a paged request or not.
*
* @return true if for paging, false otherwise
*/
public boolean isPaging()
{
return false;
}
/**
* Whether the range queried by this {@code DataRange} actually wraps around.
*
* @return whether the range queried by this {@code DataRange} actually wraps around.
*/
public boolean isWrapAround()
{
// Only range can ever wrap
return keyRange instanceof Range && ((Range)keyRange).isWrapAround();
}
/**
* Whether the provided ring position is covered by this {@code DataRange}.
*
* @return whether the provided ring position is covered by this {@code DataRange}.
*/
public boolean contains(PartitionPosition pos)
{
return keyRange.contains(pos);
}
/**
* Whether this {@code DataRange} queries everything (has no restriction neither on the
* partition queried, nor within the queried partition).
*
* @return Whether this {@code DataRange} queries everything.
*/
public boolean isUnrestricted()
{
return startKey().isMinimum() && stopKey().isMinimum() && clusteringIndexFilter.selectsAllPartition();
}
public boolean selectsAllPartition()
{
return clusteringIndexFilter.selectsAllPartition();
}
/**
* The clustering index filter to use for the provided key.
*
* This may or may not be the same filter for all keys (that is, paging range
* use a different filter for their start key).
*
* @param key the partition key for which we want the clustering index filter.
*
* @return the clustering filter to use for {@code key}.
*/
public ClusteringIndexFilter clusteringIndexFilter(DecoratedKey key)
{
return clusteringIndexFilter;
}
/**
* Returns a new {@code DataRange} for use when paging {@code this} range.
*
* @param range the range of partition keys to query.
* @param comparator the comparator for the table queried.
* @param lastReturned the clustering for the last result returned by the previous page, i.e. the result we want to start our new page
* from. This last returned must correspond to left bound of {@code range} (in other words, {@code range.left} must be the
* partition key for that {@code lastReturned} result).
* @param inclusive whether or not we want to include the {@code lastReturned} in the newly returned page of results.
*
* @return a new {@code DataRange} suitable for paging {@code this} range given the {@code lastRetuned} result of the previous page.
*/
public DataRange forPaging(AbstractBounds range, ClusteringComparator comparator, Clustering lastReturned, boolean inclusive)
{
return new Paging(range, clusteringIndexFilter, comparator, lastReturned, inclusive);
}
/**
* Returns a new {@code DataRange} equivalent to {@code this} one but restricted to the provided sub-range.
*
* @param range the sub-range to use for the newly returned data range. Note that assumes that {@code range} is a proper
* sub-range of the initial range but doesn't validate it. You should make sure to only provided sub-ranges however or this
* might throw off the paging case (see Paging.forSubRange()).
*
* @return a new {@code DataRange} using {@code range} as partition key range and the clustering index filter filter from {@code this}.
*/
public DataRange forSubRange(AbstractBounds range)
{
return new DataRange(range, clusteringIndexFilter);
}
public String toString(CFMetaData metadata)
{
return String.format("range=%s pfilter=%s", keyRange.getString(metadata.getKeyValidator()), clusteringIndexFilter.toString(metadata));
}
public String toCQLString(CFMetaData metadata)
{
if (isUnrestricted())
return "UNRESTRICTED";
StringBuilder sb = new StringBuilder();
boolean needAnd = false;
if (!startKey().isMinimum())
{
appendClause(startKey(), sb, metadata, true, keyRange.isStartInclusive());
needAnd = true;
}
if (!stopKey().isMinimum())
{
if (needAnd)
sb.append(" AND ");
appendClause(stopKey(), sb, metadata, false, keyRange.isEndInclusive());
needAnd = true;
}
String filterString = clusteringIndexFilter.toCQLString(metadata);
if (!filterString.isEmpty())
sb.append(needAnd ? " AND " : "").append(filterString);
return sb.toString();
}
private void appendClause(PartitionPosition pos, StringBuilder sb, CFMetaData metadata, boolean isStart, boolean isInclusive)
{
sb.append("token(");
sb.append(ColumnDefinition.toCQLString(metadata.partitionKeyColumns()));
sb.append(") ").append(getOperator(isStart, isInclusive)).append(" ");
if (pos instanceof DecoratedKey)
{
sb.append("token(");
appendKeyString(sb, metadata.getKeyValidator(), ((DecoratedKey)pos).getKey());
sb.append(")");
}
else
{
sb.append(((Token.KeyBound)pos).getToken());
}
}
private static String getOperator(boolean isStart, boolean isInclusive)
{
return isStart
? (isInclusive ? ">=" : ">")
: (isInclusive ? "<=" : "<");
}
// TODO: this is reused in SinglePartitionReadCommand but this should not really be here. Ideally
// we need a more "native" handling of composite partition keys.
public static void appendKeyString(StringBuilder sb, AbstractType type, ByteBuffer key)
{
if (type instanceof CompositeType)
{
CompositeType ct = (CompositeType)type;
ByteBuffer[] values = ct.split(key);
for (int i = 0; i < ct.types.size(); i++)
sb.append(i == 0 ? "" : ", ").append(ct.types.get(i).getString(values[i]));
}
else
{
sb.append(type.getString(key));
}
}
/**
* Specialized {@code DataRange} used for the paging case.
*
* It uses the clustering of the last result of the previous page to restrict the filter on the
* first queried partition (the one for that last result) so it only fetch results that follow that
* last result. In other words, this makes sure this resume paging where we left off.
*/
public static class Paging extends DataRange
{
private final ClusteringComparator comparator;
private final Clustering lastReturned;
private final boolean inclusive;
private Paging(AbstractBounds range,
ClusteringIndexFilter filter,
ClusteringComparator comparator,
Clustering lastReturned,
boolean inclusive)
{
super(range, filter);
// When using a paging range, we don't allow wrapped ranges, as it's unclear how to handle them properly.
// This is ok for now since we only need this in range queries, and the range are "unwrapped" in that case.
assert !(range instanceof Range) || !((Range)range).isWrapAround() || range.right.isMinimum() : range;
assert lastReturned != null;
this.comparator = comparator;
this.lastReturned = lastReturned;
this.inclusive = inclusive;
}
@Override
public ClusteringIndexFilter clusteringIndexFilter(DecoratedKey key)
{
return key.equals(startKey())
? clusteringIndexFilter.forPaging(comparator, lastReturned, inclusive)
: clusteringIndexFilter;
}
@Override
public DataRange forSubRange(AbstractBounds range)
{
// This is called for subrange of the initial range. So either it's the beginning of the initial range,
// and we need to preserver lastReturned, or it's not, and we don't care about it anymore.
return range.left.equals(keyRange().left)
? new Paging(range, clusteringIndexFilter, comparator, lastReturned, inclusive)
: new DataRange(range, clusteringIndexFilter);
}
/**
* @return the last Clustering that was returned (in the previous page)
*/
public Clustering getLastReturned()
{
return lastReturned;
}
@Override
public boolean isPaging()
{
return true;
}
@Override
public boolean isUnrestricted()
{
return false;
}
@Override
public String toString(CFMetaData metadata)
{
return String.format("range=%s (paging) pfilter=%s lastReturned=%s (%s)",
keyRange.getString(metadata.getKeyValidator()),
clusteringIndexFilter.toString(metadata),
lastReturned.toString(metadata),
inclusive ? "included" : "excluded");
}
}
public static class Serializer
{
public void serialize(DataRange range, DataOutputPlus out, int version, CFMetaData metadata) throws IOException
{
AbstractBounds.rowPositionSerializer.serialize(range.keyRange, out, version);
ClusteringIndexFilter.serializer.serialize(range.clusteringIndexFilter, out, version);
boolean isPaging = range instanceof Paging;
out.writeBoolean(isPaging);
if (isPaging)
{
Clustering.serializer.serialize(((Paging)range).lastReturned, out, version, metadata.comparator.subtypes());
out.writeBoolean(((Paging)range).inclusive);
}
}
public DataRange deserialize(DataInputPlus in, int version, CFMetaData metadata) throws IOException
{
AbstractBounds range = AbstractBounds.rowPositionSerializer.deserialize(in, metadata.partitioner, version);
ClusteringIndexFilter filter = ClusteringIndexFilter.serializer.deserialize(in, version, metadata);
if (in.readBoolean())
{
ClusteringComparator comparator = metadata.comparator;
Clustering lastReturned = Clustering.serializer.deserialize(in, version, comparator.subtypes());
boolean inclusive = in.readBoolean();
return new Paging(range, filter, comparator, lastReturned, inclusive);
}
else
{
return new DataRange(range, filter);
}
}
public long serializedSize(DataRange range, int version, CFMetaData metadata)
{
long size = AbstractBounds.rowPositionSerializer.serializedSize(range.keyRange, version)
+ ClusteringIndexFilter.serializer.serializedSize(range.clusteringIndexFilter, version)
+ 1; // isPaging boolean
if (range instanceof Paging)
{
size += Clustering.serializer.serializedSize(((Paging)range).lastReturned, version, metadata.comparator.subtypes());
size += 1; // inclusive boolean
}
return size;
}
}
}