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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 java.util.*;
import java.util.stream.Collectors;
import com.google.common.collect.Iterables;
import com.google.common.collect.Sets;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.cassandra.cache.IRowCacheEntry;
import org.apache.cassandra.cache.RowCacheKey;
import org.apache.cassandra.cache.RowCacheSentinel;
import org.apache.cassandra.concurrent.Stage;
import org.apache.cassandra.concurrent.StageManager;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.ColumnDefinition;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.lifecycle.*;
import org.apache.cassandra.db.filter.*;
import org.apache.cassandra.db.partitions.*;
import org.apache.cassandra.db.rows.*;
import org.apache.cassandra.db.transform.Transformation;
import org.apache.cassandra.exceptions.RequestExecutionException;
import org.apache.cassandra.io.sstable.format.SSTableReader;
import org.apache.cassandra.io.sstable.format.SSTableReadsListener;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.metrics.TableMetrics;
import org.apache.cassandra.net.MessageOut;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.schema.IndexMetadata;
import org.apache.cassandra.service.CacheService;
import org.apache.cassandra.service.ClientState;
import org.apache.cassandra.service.StorageProxy;
import org.apache.cassandra.service.pager.*;
import org.apache.cassandra.thrift.ThriftResultsMerger;
import org.apache.cassandra.tracing.Tracing;
import org.apache.cassandra.transport.ProtocolVersion;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.SearchIterator;
import org.apache.cassandra.utils.btree.BTreeSet;
/**
* A read command that selects a (part of a) single partition.
*/
public class SinglePartitionReadCommand extends ReadCommand
{
protected static final SelectionDeserializer selectionDeserializer = new Deserializer();
private final DecoratedKey partitionKey;
private final ClusteringIndexFilter clusteringIndexFilter;
private int oldestUnrepairedTombstone = Integer.MAX_VALUE;
public SinglePartitionReadCommand(boolean isDigest,
int digestVersion,
boolean isForThrift,
CFMetaData metadata,
int nowInSec,
ColumnFilter columnFilter,
RowFilter rowFilter,
DataLimits limits,
DecoratedKey partitionKey,
ClusteringIndexFilter clusteringIndexFilter)
{
super(Kind.SINGLE_PARTITION, isDigest, digestVersion, isForThrift, metadata, nowInSec, columnFilter, rowFilter, limits);
assert partitionKey.getPartitioner() == metadata.partitioner;
this.partitionKey = partitionKey;
this.clusteringIndexFilter = clusteringIndexFilter;
}
/**
* Creates a new read command on a single partition.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param columnFilter the column filter to use for the query.
* @param rowFilter the row filter to use for the query.
* @param limits the limits to use for the query.
* @param partitionKey the partition key for the partition to query.
* @param clusteringIndexFilter the clustering index filter to use for the query.
*
* @return a newly created read command.
*/
public static SinglePartitionReadCommand create(CFMetaData metadata,
int nowInSec,
ColumnFilter columnFilter,
RowFilter rowFilter,
DataLimits limits,
DecoratedKey partitionKey,
ClusteringIndexFilter clusteringIndexFilter)
{
return create(false, metadata, nowInSec, columnFilter, rowFilter, limits, partitionKey, clusteringIndexFilter);
}
/**
* Creates a new read command on a single partition for thrift.
*
* @param isForThrift whether the query is for thrift or not.
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param columnFilter the column filter to use for the query.
* @param rowFilter the row filter to use for the query.
* @param limits the limits to use for the query.
* @param partitionKey the partition key for the partition to query.
* @param clusteringIndexFilter the clustering index filter to use for the query.
*
* @return a newly created read command.
*/
public static SinglePartitionReadCommand create(boolean isForThrift,
CFMetaData metadata,
int nowInSec,
ColumnFilter columnFilter,
RowFilter rowFilter,
DataLimits limits,
DecoratedKey partitionKey,
ClusteringIndexFilter clusteringIndexFilter)
{
return new SinglePartitionReadCommand(false, 0, isForThrift, metadata, nowInSec, columnFilter, rowFilter, limits, partitionKey, clusteringIndexFilter);
}
/**
* Creates a new read command on a single partition.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
* @param columnFilter the column filter to use for the query.
* @param filter the clustering index filter to use for the query.
*
* @return a newly created read command. The returned command will use no row filter and have no limits.
*/
public static SinglePartitionReadCommand create(CFMetaData metadata, int nowInSec, DecoratedKey key, ColumnFilter columnFilter, ClusteringIndexFilter filter)
{
return create(metadata, nowInSec, columnFilter, RowFilter.NONE, DataLimits.NONE, key, filter);
}
/**
* Creates a new read command that queries a single partition in its entirety.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
*
* @return a newly created read command that queries all the rows of {@code key}.
*/
public static SinglePartitionReadCommand fullPartitionRead(CFMetaData metadata, int nowInSec, DecoratedKey key)
{
return SinglePartitionReadCommand.create(metadata, nowInSec, key, Slices.ALL);
}
/**
* Creates a new read command that queries a single partition in its entirety.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
*
* @return a newly created read command that queries all the rows of {@code key}.
*/
public static SinglePartitionReadCommand fullPartitionRead(CFMetaData metadata, int nowInSec, ByteBuffer key)
{
return SinglePartitionReadCommand.create(metadata, nowInSec, metadata.decorateKey(key), Slices.ALL);
}
/**
* Creates a new single partition slice command for the provided single slice.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
* @param slice the slice of rows to query.
*
* @return a newly created read command that queries {@code slice} in {@code key}. The returned query will
* query every columns for the table (without limit or row filtering) and be in forward order.
*/
public static SinglePartitionReadCommand create(CFMetaData metadata, int nowInSec, DecoratedKey key, Slice slice)
{
return create(metadata, nowInSec, key, Slices.with(metadata.comparator, slice));
}
/**
* Creates a new single partition slice command for the provided slices.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
* @param slices the slices of rows to query.
*
* @return a newly created read command that queries the {@code slices} in {@code key}. The returned query will
* query every columns for the table (without limit or row filtering) and be in forward order.
*/
public static SinglePartitionReadCommand create(CFMetaData metadata, int nowInSec, DecoratedKey key, Slices slices)
{
ClusteringIndexSliceFilter filter = new ClusteringIndexSliceFilter(slices, false);
return SinglePartitionReadCommand.create(metadata, nowInSec, ColumnFilter.all(metadata), RowFilter.NONE, DataLimits.NONE, key, filter);
}
/**
* Creates a new single partition slice command for the provided slices.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
* @param slices the slices of rows to query.
*
* @return a newly created read command that queries the {@code slices} in {@code key}. The returned query will
* query every columns for the table (without limit or row filtering) and be in forward order.
*/
public static SinglePartitionReadCommand create(CFMetaData metadata, int nowInSec, ByteBuffer key, Slices slices)
{
return create(metadata, nowInSec, metadata.decorateKey(key), slices);
}
/**
* Creates a new single partition name command for the provided rows.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
* @param names the clustering for the rows to query.
*
* @return a newly created read command that queries the {@code names} in {@code key}. The returned query will
* query every columns (without limit or row filtering) and be in forward order.
*/
public static SinglePartitionReadCommand create(CFMetaData metadata, int nowInSec, DecoratedKey key, NavigableSet names)
{
ClusteringIndexNamesFilter filter = new ClusteringIndexNamesFilter(names, false);
return SinglePartitionReadCommand.create(metadata, nowInSec, ColumnFilter.all(metadata), RowFilter.NONE, DataLimits.NONE, key, filter);
}
/**
* Creates a new single partition name command for the provided row.
*
* @param metadata the table to query.
* @param nowInSec the time in seconds to use are "now" for this query.
* @param key the partition key for the partition to query.
* @param name the clustering for the row to query.
*
* @return a newly created read command that queries {@code name} in {@code key}. The returned query will
* query every columns (without limit or row filtering).
*/
public static SinglePartitionReadCommand create(CFMetaData metadata, int nowInSec, DecoratedKey key, Clustering name)
{
return create(metadata, nowInSec, key, FBUtilities.singleton(name, metadata.comparator));
}
public SinglePartitionReadCommand copy()
{
return new SinglePartitionReadCommand(isDigestQuery(), digestVersion(), isForThrift(), metadata(), nowInSec(), columnFilter(), rowFilter(), limits(), partitionKey(), clusteringIndexFilter());
}
public DecoratedKey partitionKey()
{
return partitionKey;
}
public ClusteringIndexFilter clusteringIndexFilter()
{
return clusteringIndexFilter;
}
public ClusteringIndexFilter clusteringIndexFilter(DecoratedKey key)
{
return clusteringIndexFilter;
}
public long getTimeout()
{
return DatabaseDescriptor.getReadRpcTimeout();
}
public boolean selectsKey(DecoratedKey key)
{
if (!this.partitionKey().equals(key))
return false;
return rowFilter().partitionKeyRestrictionsAreSatisfiedBy(key, metadata().getKeyValidator());
}
public boolean selectsClustering(DecoratedKey key, Clustering clustering)
{
if (clustering == Clustering.STATIC_CLUSTERING)
return !columnFilter().fetchedColumns().statics.isEmpty();
if (!clusteringIndexFilter().selects(clustering))
return false;
return rowFilter().clusteringKeyRestrictionsAreSatisfiedBy(clustering);
}
/**
* Returns a new command suitable to paging from the last returned row.
*
* @param lastReturned the last row returned by the previous page. The newly created command
* will only query row that comes after this (in query order). This can be {@code null} if this
* is the first page.
* @param limits the limits to use for the page to query.
*
* @return the newly create command.
*/
public SinglePartitionReadCommand forPaging(Clustering lastReturned, DataLimits limits)
{
// We shouldn't have set digest yet when reaching that point
assert !isDigestQuery();
return create(isForThrift(),
metadata(),
nowInSec(),
columnFilter(),
rowFilter(),
limits,
partitionKey(),
lastReturned == null ? clusteringIndexFilter() : clusteringIndexFilter.forPaging(metadata().comparator, lastReturned, false));
}
public SinglePartitionReadCommand withUpdatedLimit(DataLimits newLimits)
{
return new SinglePartitionReadCommand(isDigestQuery(),
digestVersion(),
isForThrift(),
metadata(),
nowInSec(),
columnFilter(),
rowFilter(),
newLimits,
partitionKey,
clusteringIndexFilter);
}
public PartitionIterator execute(ConsistencyLevel consistency, ClientState clientState, long queryStartNanoTime) throws RequestExecutionException
{
return StorageProxy.read(Group.one(this), consistency, clientState, queryStartNanoTime);
}
public SinglePartitionPager getPager(PagingState pagingState, ProtocolVersion protocolVersion)
{
return getPager(this, pagingState, protocolVersion);
}
private static SinglePartitionPager getPager(SinglePartitionReadCommand command, PagingState pagingState, ProtocolVersion protocolVersion)
{
return new SinglePartitionPager(command, pagingState, protocolVersion);
}
protected void recordLatency(TableMetrics metric, long latencyNanos)
{
metric.readLatency.addNano(latencyNanos);
}
@SuppressWarnings("resource") // we close the created iterator through closing the result of this method (and SingletonUnfilteredPartitionIterator ctor cannot fail)
protected UnfilteredPartitionIterator queryStorage(final ColumnFamilyStore cfs, ReadExecutionController executionController)
{
UnfilteredRowIterator partition = cfs.isRowCacheEnabled()
? getThroughCache(cfs, executionController)
: queryMemtableAndDisk(cfs, executionController);
return new SingletonUnfilteredPartitionIterator(partition, isForThrift());
}
/**
* Fetch the rows requested if in cache; if not, read it from disk and cache it.
*
* If the partition is cached, and the filter given is within its bounds, we return
* from cache, otherwise from disk.
*
* If the partition is is not cached, we figure out what filter is "biggest", read
* that from disk, then filter the result and either cache that or return it.
*/
private UnfilteredRowIterator getThroughCache(ColumnFamilyStore cfs, ReadExecutionController executionController)
{
assert !cfs.isIndex(); // CASSANDRA-5732
assert cfs.isRowCacheEnabled() : String.format("Row cache is not enabled on table [%s]", cfs.name);
RowCacheKey key = new RowCacheKey(metadata().ksAndCFName, partitionKey());
// Attempt a sentinel-read-cache sequence. if a write invalidates our sentinel, we'll return our
// (now potentially obsolete) data, but won't cache it. see CASSANDRA-3862
// TODO: don't evict entire partitions on writes (#2864)
IRowCacheEntry cached = CacheService.instance.rowCache.get(key);
if (cached != null)
{
if (cached instanceof RowCacheSentinel)
{
// Some other read is trying to cache the value, just do a normal non-caching read
Tracing.trace("Row cache miss (race)");
cfs.metric.rowCacheMiss.inc();
return queryMemtableAndDisk(cfs, executionController);
}
CachedPartition cachedPartition = (CachedPartition)cached;
if (cfs.isFilterFullyCoveredBy(clusteringIndexFilter(), limits(), cachedPartition, nowInSec()))
{
cfs.metric.rowCacheHit.inc();
Tracing.trace("Row cache hit");
UnfilteredRowIterator unfilteredRowIterator = clusteringIndexFilter().getUnfilteredRowIterator(columnFilter(), cachedPartition);
cfs.metric.updateSSTableIterated(0);
return unfilteredRowIterator;
}
cfs.metric.rowCacheHitOutOfRange.inc();
Tracing.trace("Ignoring row cache as cached value could not satisfy query");
return queryMemtableAndDisk(cfs, executionController);
}
cfs.metric.rowCacheMiss.inc();
Tracing.trace("Row cache miss");
// Note that on tables with no clustering keys, any positive value of
// rowsToCache implies caching the full partition
boolean cacheFullPartitions = metadata().clusteringColumns().size() > 0 ?
metadata().params.caching.cacheAllRows() :
metadata().params.caching.cacheRows();
// To be able to cache what we read, what we read must at least covers what the cache holds, that
// is the 'rowsToCache' first rows of the partition. We could read those 'rowsToCache' first rows
// systematically, but we'd have to "extend" that to whatever is needed for the user query that the
// 'rowsToCache' first rows don't cover and it's not trivial with our existing filters. So currently
// we settle for caching what we read only if the user query does query the head of the partition since
// that's the common case of when we'll be able to use the cache anyway. One exception is if we cache
// full partitions, in which case we just always read it all and cache.
if (cacheFullPartitions || clusteringIndexFilter().isHeadFilter())
{
RowCacheSentinel sentinel = new RowCacheSentinel();
boolean sentinelSuccess = CacheService.instance.rowCache.putIfAbsent(key, sentinel);
boolean sentinelReplaced = false;
try
{
int rowsToCache = metadata().params.caching.rowsPerPartitionToCache();
@SuppressWarnings("resource") // we close on exception or upon closing the result of this method
UnfilteredRowIterator iter = SinglePartitionReadCommand.fullPartitionRead(metadata(), nowInSec(), partitionKey()).queryMemtableAndDisk(cfs, executionController);
try
{
// We want to cache only rowsToCache rows
CachedPartition toCache = CachedBTreePartition.create(DataLimits.cqlLimits(rowsToCache).filter(iter, nowInSec()), nowInSec());
if (sentinelSuccess && !toCache.isEmpty())
{
Tracing.trace("Caching {} rows", toCache.rowCount());
CacheService.instance.rowCache.replace(key, sentinel, toCache);
// Whether or not the previous replace has worked, our sentinel is not in the cache anymore
sentinelReplaced = true;
}
// We then re-filter out what this query wants.
// Note that in the case where we don't cache full partitions, it's possible that the current query is interested in more
// than what we've cached, so we can't just use toCache.
UnfilteredRowIterator cacheIterator = clusteringIndexFilter().getUnfilteredRowIterator(columnFilter(), toCache);
if (cacheFullPartitions)
{
// Everything is guaranteed to be in 'toCache', we're done with 'iter'
assert !iter.hasNext();
iter.close();
return cacheIterator;
}
return UnfilteredRowIterators.concat(cacheIterator, clusteringIndexFilter().filterNotIndexed(columnFilter(), iter));
}
catch (RuntimeException | Error e)
{
iter.close();
throw e;
}
}
finally
{
if (sentinelSuccess && !sentinelReplaced)
cfs.invalidateCachedPartition(key);
}
}
Tracing.trace("Fetching data but not populating cache as query does not query from the start of the partition");
return queryMemtableAndDisk(cfs, executionController);
}
/**
* Queries both memtable and sstables to fetch the result of this query.
*
* Please note that this method:
* 1) does not check the row cache.
* 2) does not apply the query limit, nor the row filter (and so ignore 2ndary indexes).
* Those are applied in {@link ReadCommand#executeLocally}.
* 3) does not record some of the read metrics (latency, scanned cells histograms) nor
* throws TombstoneOverwhelmingException.
* It is publicly exposed because there is a few places where that is exactly what we want,
* but it should be used only where you know you don't need thoses things.
*
* Also note that one must have created a {@code ReadExecutionController} on the queried table and we require it as
* a parameter to enforce that fact, even though it's not explicitlly used by the method.
*/
public UnfilteredRowIterator queryMemtableAndDisk(ColumnFamilyStore cfs, ReadExecutionController executionController)
{
assert executionController != null && executionController.validForReadOn(cfs);
Tracing.trace("Executing single-partition query on {}", cfs.name);
return queryMemtableAndDiskInternal(cfs);
}
@Override
protected int oldestUnrepairedTombstone()
{
return oldestUnrepairedTombstone;
}
private UnfilteredRowIterator queryMemtableAndDiskInternal(ColumnFamilyStore cfs)
{
/*
* We have 2 main strategies:
* 1) We query memtables and sstables simulateneously. This is our most generic strategy and the one we use
* unless we have a names filter that we know we can optimize futher.
* 2) If we have a name filter (so we query specific rows), we can make a bet: that all column for all queried row
* will have data in the most recent sstable(s), thus saving us from reading older ones. This does imply we
* have a way to guarantee we have all the data for what is queried, which is only possible for name queries
* and if we have neither non-frozen collections/UDTs nor counters (indeed, for a non-frozen collection or UDT,
* we can't guarantee an older sstable won't have some elements that weren't in the most recent sstables,
* and counters are intrinsically a collection of shards and so have the same problem).
*/
if (clusteringIndexFilter() instanceof ClusteringIndexNamesFilter && !queriesMulticellType())
return queryMemtableAndSSTablesInTimestampOrder(cfs, (ClusteringIndexNamesFilter)clusteringIndexFilter());
Tracing.trace("Acquiring sstable references");
ColumnFamilyStore.ViewFragment view = cfs.select(View.select(SSTableSet.LIVE, partitionKey()));
List iterators = new ArrayList<>(Iterables.size(view.memtables) + view.sstables.size());
ClusteringIndexFilter filter = clusteringIndexFilter();
long minTimestamp = Long.MAX_VALUE;
try
{
for (Memtable memtable : view.memtables)
{
Partition partition = memtable.getPartition(partitionKey());
if (partition == null)
continue;
minTimestamp = Math.min(minTimestamp, memtable.getMinTimestamp());
@SuppressWarnings("resource") // 'iter' is added to iterators which is closed on exception, or through the closing of the final merged iterator
UnfilteredRowIterator iter = filter.getUnfilteredRowIterator(columnFilter(), partition);
oldestUnrepairedTombstone = Math.min(oldestUnrepairedTombstone, partition.stats().minLocalDeletionTime);
iterators.add(isForThrift() ? ThriftResultsMerger.maybeWrap(iter, nowInSec()) : iter);
}
/*
* We can't eliminate full sstables based on the timestamp of what we've already read like
* in collectTimeOrderedData, but we still want to eliminate sstable whose maxTimestamp < mostRecentTombstone
* we've read. We still rely on the sstable ordering by maxTimestamp since if
* maxTimestamp_s1 > maxTimestamp_s0,
* we're guaranteed that s1 cannot have a row tombstone such that
* timestamp(tombstone) > maxTimestamp_s0
* since we necessarily have
* timestamp(tombstone) <= maxTimestamp_s1
* In other words, iterating in maxTimestamp order allow to do our mostRecentPartitionTombstone elimination
* in one pass, and minimize the number of sstables for which we read a partition tombstone.
*/
Collections.sort(view.sstables, SSTableReader.maxTimestampComparator);
long mostRecentPartitionTombstone = Long.MIN_VALUE;
int nonIntersectingSSTables = 0;
List skippedSSTablesWithTombstones = null;
SSTableReadMetricsCollector metricsCollector = new SSTableReadMetricsCollector();
for (SSTableReader sstable : view.sstables)
{
// if we've already seen a partition tombstone with a timestamp greater
// than the most recent update to this sstable, we can skip it
if (sstable.getMaxTimestamp() < mostRecentPartitionTombstone)
break;
if (!shouldInclude(sstable))
{
nonIntersectingSSTables++;
if (sstable.mayHaveTombstones())
{ // if sstable has tombstones we need to check after one pass if it can be safely skipped
if (skippedSSTablesWithTombstones == null)
skippedSSTablesWithTombstones = new ArrayList<>();
skippedSSTablesWithTombstones.add(sstable);
}
continue;
}
minTimestamp = Math.min(minTimestamp, sstable.getMinTimestamp());
@SuppressWarnings("resource") // 'iter' is added to iterators which is closed on exception,
// or through the closing of the final merged iterator
UnfilteredRowIteratorWithLowerBound iter = makeIterator(cfs, sstable, true, metricsCollector);
if (!sstable.isRepaired())
oldestUnrepairedTombstone = Math.min(oldestUnrepairedTombstone, sstable.getMinLocalDeletionTime());
iterators.add(iter);
mostRecentPartitionTombstone = Math.max(mostRecentPartitionTombstone,
iter.partitionLevelDeletion().markedForDeleteAt());
}
int includedDueToTombstones = 0;
// Check for sstables with tombstones that are not expired
if (skippedSSTablesWithTombstones != null)
{
for (SSTableReader sstable : skippedSSTablesWithTombstones)
{
if (sstable.getMaxTimestamp() <= minTimestamp)
continue;
@SuppressWarnings("resource") // 'iter' is added to iterators which is close on exception,
// or through the closing of the final merged iterator
UnfilteredRowIteratorWithLowerBound iter = makeIterator(cfs, sstable, false, metricsCollector);
if (!sstable.isRepaired())
oldestUnrepairedTombstone = Math.min(oldestUnrepairedTombstone, sstable.getMinLocalDeletionTime());
iterators.add(iter);
includedDueToTombstones++;
}
}
if (Tracing.isTracing())
Tracing.trace("Skipped {}/{} non-slice-intersecting sstables, included {} due to tombstones",
nonIntersectingSSTables, view.sstables.size(), includedDueToTombstones);
if (iterators.isEmpty())
return EmptyIterators.unfilteredRow(cfs.metadata, partitionKey(), filter.isReversed());
StorageHook.instance.reportRead(cfs.metadata.cfId, partitionKey());
return withSSTablesIterated(iterators, cfs.metric, metricsCollector);
}
catch (RuntimeException | Error e)
{
try
{
FBUtilities.closeAll(iterators);
}
catch (Exception suppressed)
{
e.addSuppressed(suppressed);
}
throw e;
}
}
private boolean shouldInclude(SSTableReader sstable)
{
// If some static columns are queried, we should always include the sstable: the clustering values stats of the sstable
// don't tell us if the sstable contains static values in particular.
// TODO: we could record if a sstable contains any static value at all.
if (!columnFilter().fetchedColumns().statics.isEmpty())
return true;
return clusteringIndexFilter().shouldInclude(sstable);
}
private UnfilteredRowIteratorWithLowerBound makeIterator(ColumnFamilyStore cfs,
final SSTableReader sstable,
boolean applyThriftTransformation,
SSTableReadsListener listener)
{
return StorageHook.instance.makeRowIteratorWithLowerBound(cfs,
partitionKey(),
sstable,
clusteringIndexFilter(),
columnFilter(),
isForThrift(),
nowInSec(),
applyThriftTransformation,
listener);
}
/**
* Return a wrapped iterator that when closed will update the sstables iterated and READ sample metrics.
* Note that we cannot use the Transformations framework because they greedily get the static row, which
* would cause all iterators to be initialized and hence all sstables to be accessed.
*/
private UnfilteredRowIterator withSSTablesIterated(List iterators,
TableMetrics metrics,
SSTableReadMetricsCollector metricsCollector)
{
@SuppressWarnings("resource") // Closed through the closing of the result of the caller method.
UnfilteredRowIterator merged = UnfilteredRowIterators.merge(iterators, nowInSec());
if (!merged.isEmpty())
{
DecoratedKey key = merged.partitionKey();
metrics.samplers.get(TableMetrics.Sampler.READS).addSample(key.getKey(), key.hashCode(), 1);
}
class UpdateSstablesIterated extends Transformation
{
public void onPartitionClose()
{
int mergedSSTablesIterated = metricsCollector.getMergedSSTables();
metrics.updateSSTableIterated(mergedSSTablesIterated);
Tracing.trace("Merged data from memtables and {} sstables", mergedSSTablesIterated);
}
};
return Transformation.apply(merged, new UpdateSstablesIterated());
}
private boolean queriesMulticellType()
{
for (ColumnDefinition column : columnFilter().fetchedColumns())
{
if (column.type.isMultiCell() || column.type.isCounter())
return true;
}
return false;
}
/**
* Do a read by querying the memtable(s) first, and then each relevant sstables sequentially by order of the sstable
* max timestamp.
*
* This is used for names query in the hope of only having to query the 1 or 2 most recent query and then knowing nothing
* more recent could be in the older sstables (which we can only guarantee if we know exactly which row we queries, and if
* no collection or counters are included).
* This method assumes the filter is a {@code ClusteringIndexNamesFilter}.
*/
private UnfilteredRowIterator queryMemtableAndSSTablesInTimestampOrder(ColumnFamilyStore cfs, ClusteringIndexNamesFilter filter)
{
Tracing.trace("Acquiring sstable references");
ColumnFamilyStore.ViewFragment view = cfs.select(View.select(SSTableSet.LIVE, partitionKey()));
ImmutableBTreePartition result = null;
Tracing.trace("Merging memtable contents");
for (Memtable memtable : view.memtables)
{
Partition partition = memtable.getPartition(partitionKey());
if (partition == null)
continue;
try (UnfilteredRowIterator iter = filter.getUnfilteredRowIterator(columnFilter(), partition))
{
if (iter.isEmpty())
continue;
result = add(isForThrift() ? ThriftResultsMerger.maybeWrap(iter, nowInSec()) : iter, result, filter, false);
}
}
/* add the SSTables on disk */
Collections.sort(view.sstables, SSTableReader.maxTimestampComparator);
boolean onlyUnrepaired = true;
// read sorted sstables
SSTableReadMetricsCollector metricsCollector = new SSTableReadMetricsCollector();
for (SSTableReader sstable : view.sstables)
{
// if we've already seen a partition tombstone with a timestamp greater
// than the most recent update to this sstable, we're done, since the rest of the sstables
// will also be older
if (result != null && sstable.getMaxTimestamp() < result.partitionLevelDeletion().markedForDeleteAt())
break;
long currentMaxTs = sstable.getMaxTimestamp();
filter = reduceFilter(filter, result, currentMaxTs);
if (filter == null)
break;
if (!shouldInclude(sstable))
{
// This mean that nothing queried by the filter can be in the sstable. One exception is the top-level partition deletion
// however: if it is set, it impacts everything and must be included. Getting that top-level partition deletion costs us
// some seek in general however (unless the partition is indexed and is in the key cache), so we first check if the sstable
// has any tombstone at all as a shortcut.
if (!sstable.mayHaveTombstones())
continue; // no tombstone at all, we can skip that sstable
// We need to get the partition deletion and include it if it's live. In any case though, we're done with that sstable.
try (UnfilteredRowIterator iter = StorageHook.instance.makeRowIterator(cfs,
sstable,
partitionKey(),
filter.getSlices(metadata()),
columnFilter(),
filter.isReversed(),
isForThrift(),
metricsCollector))
{
if (!iter.partitionLevelDeletion().isLive())
result = add(UnfilteredRowIterators.noRowsIterator(iter.metadata(), iter.partitionKey(), Rows.EMPTY_STATIC_ROW, iter.partitionLevelDeletion(), filter.isReversed()), result, filter, sstable.isRepaired());
else
result = add(iter, result, filter, sstable.isRepaired());
}
continue;
}
try (UnfilteredRowIterator iter = StorageHook.instance.makeRowIterator(cfs,
sstable,
partitionKey(),
filter.getSlices(metadata()),
columnFilter(),
filter.isReversed(),
isForThrift(),
metricsCollector))
{
if (iter.isEmpty())
continue;
if (sstable.isRepaired())
onlyUnrepaired = false;
result = add(isForThrift() ? ThriftResultsMerger.maybeWrap(iter, nowInSec()) : iter, result, filter, sstable.isRepaired());
}
}
cfs.metric.updateSSTableIterated(metricsCollector.getMergedSSTables());
if (result == null || result.isEmpty())
return EmptyIterators.unfilteredRow(metadata(), partitionKey(), false);
DecoratedKey key = result.partitionKey();
cfs.metric.samplers.get(TableMetrics.Sampler.READS).addSample(key.getKey(), key.hashCode(), 1);
StorageHook.instance.reportRead(cfs.metadata.cfId, partitionKey());
// "hoist up" the requested data into a more recent sstable
if (metricsCollector.getMergedSSTables() > cfs.getMinimumCompactionThreshold()
&& onlyUnrepaired
&& !cfs.isAutoCompactionDisabled()
&& cfs.getCompactionStrategyManager().shouldDefragment())
{
// !!WARNING!! if we stop copying our data to a heap-managed object,
// we will need to track the lifetime of this mutation as well
Tracing.trace("Defragmenting requested data");
try (UnfilteredRowIterator iter = result.unfilteredIterator(columnFilter(), Slices.ALL, false))
{
final Mutation mutation = new Mutation(PartitionUpdate.fromIterator(iter, columnFilter()));
StageManager.getStage(Stage.MUTATION).execute(() -> {
// skipping commitlog and index updates is fine since we're just de-fragmenting existing data
Keyspace.open(mutation.getKeyspaceName()).apply(mutation, false, false);
});
}
}
return result.unfilteredIterator(columnFilter(), Slices.ALL, clusteringIndexFilter().isReversed());
}
private ImmutableBTreePartition add(UnfilteredRowIterator iter, ImmutableBTreePartition result, ClusteringIndexNamesFilter filter, boolean isRepaired)
{
if (!isRepaired)
oldestUnrepairedTombstone = Math.min(oldestUnrepairedTombstone, iter.stats().minLocalDeletionTime);
int maxRows = Math.max(filter.requestedRows().size(), 1);
if (result == null)
return ImmutableBTreePartition.create(iter, maxRows);
try (UnfilteredRowIterator merged = UnfilteredRowIterators.merge(Arrays.asList(iter, result.unfilteredIterator(columnFilter(), Slices.ALL, filter.isReversed())), nowInSec()))
{
return ImmutableBTreePartition.create(merged, maxRows);
}
}
private ClusteringIndexNamesFilter reduceFilter(ClusteringIndexNamesFilter filter, Partition result, long sstableTimestamp)
{
if (result == null)
return filter;
SearchIterator searchIter = result.searchIterator(columnFilter(), false);
PartitionColumns columns = columnFilter().fetchedColumns();
NavigableSet clusterings = filter.requestedRows();
// We want to remove rows for which we have values for all requested columns. We have to deal with both static and regular rows.
// TODO: we could also remove a selected column if we've found values for every requested row but we'll leave
// that for later.
boolean removeStatic = false;
if (!columns.statics.isEmpty())
{
Row staticRow = searchIter.next(Clustering.STATIC_CLUSTERING);
removeStatic = staticRow != null && canRemoveRow(staticRow, columns.statics, sstableTimestamp);
}
NavigableSet toRemove = null;
for (Clustering clustering : clusterings)
{
Row row = searchIter.next(clustering);
if (row == null || !canRemoveRow(row, columns.regulars, sstableTimestamp))
continue;
if (toRemove == null)
toRemove = new TreeSet<>(result.metadata().comparator);
toRemove.add(clustering);
}
if (!removeStatic && toRemove == null)
return filter;
// Check if we have everything we need
boolean hasNoMoreStatic = columns.statics.isEmpty() || removeStatic;
boolean hasNoMoreClusterings = clusterings.isEmpty() || (toRemove != null && toRemove.size() == clusterings.size());
if (hasNoMoreStatic && hasNoMoreClusterings)
return null;
if (toRemove != null)
{
BTreeSet.Builder newClusterings = BTreeSet.builder(result.metadata().comparator);
newClusterings.addAll(Sets.difference(clusterings, toRemove));
clusterings = newClusterings.build();
}
return new ClusteringIndexNamesFilter(clusterings, filter.isReversed());
}
private boolean canRemoveRow(Row row, Columns requestedColumns, long sstableTimestamp)
{
// We can remove a row if it has data that is more recent that the next sstable to consider for the data that the query
// cares about. And the data we care about is 1) the row timestamp (since every query cares if the row exists or not)
// and 2) the requested columns.
if (row.primaryKeyLivenessInfo().isEmpty() || row.primaryKeyLivenessInfo().timestamp() <= sstableTimestamp)
return false;
for (ColumnDefinition column : requestedColumns)
{
Cell cell = row.getCell(column);
if (cell == null || cell.timestamp() <= sstableTimestamp)
return false;
}
return true;
}
@Override
public String toString()
{
return String.format("Read(%s.%s columns=%s rowFilter=%s limits=%s key=%s filter=%s, nowInSec=%d)",
metadata().ksName,
metadata().cfName,
columnFilter(),
rowFilter(),
limits(),
metadata().getKeyValidator().getString(partitionKey().getKey()),
clusteringIndexFilter.toString(metadata()),
nowInSec());
}
public MessageOut createMessage(int version)
{
return new MessageOut<>(MessagingService.Verb.READ, this, readSerializer);
}
protected void appendCQLWhereClause(StringBuilder sb)
{
sb.append(" WHERE ");
sb.append(ColumnDefinition.toCQLString(metadata().partitionKeyColumns())).append(" = ");
DataRange.appendKeyString(sb, metadata().getKeyValidator(), partitionKey().getKey());
// We put the row filter first because the clustering index filter can end by "ORDER BY"
if (!rowFilter().isEmpty())
sb.append(" AND ").append(rowFilter());
String filterString = clusteringIndexFilter().toCQLString(metadata());
if (!filterString.isEmpty())
sb.append(" AND ").append(filterString);
}
protected void serializeSelection(DataOutputPlus out, int version) throws IOException
{
metadata().getKeyValidator().writeValue(partitionKey().getKey(), out);
ClusteringIndexFilter.serializer.serialize(clusteringIndexFilter(), out, version);
}
protected long selectionSerializedSize(int version)
{
return metadata().getKeyValidator().writtenLength(partitionKey().getKey())
+ ClusteringIndexFilter.serializer.serializedSize(clusteringIndexFilter(), version);
}
/**
* Groups multiple single partition read commands.
*/
public static class Group implements ReadQuery
{
public final List commands;
private final DataLimits limits;
private final int nowInSec;
public Group(List commands, DataLimits limits)
{
assert !commands.isEmpty();
this.commands = commands;
this.limits = limits;
this.nowInSec = commands.get(0).nowInSec();
for (int i = 1; i < commands.size(); i++)
assert commands.get(i).nowInSec() == nowInSec;
}
public static Group one(SinglePartitionReadCommand command)
{
return new Group(Collections.singletonList(command), command.limits());
}
public PartitionIterator execute(ConsistencyLevel consistency, ClientState clientState, long queryStartNanoTime) throws RequestExecutionException
{
return StorageProxy.read(this, consistency, clientState, queryStartNanoTime);
}
public int nowInSec()
{
return nowInSec;
}
public DataLimits limits()
{
return limits;
}
public CFMetaData metadata()
{
return commands.get(0).metadata();
}
public ReadExecutionController executionController()
{
// Note that the only difference between the command in a group must be the partition key on which
// they applied. So as far as ReadOrderGroup is concerned, we can use any of the commands to start one.
return commands.get(0).executionController();
}
public PartitionIterator executeInternal(ReadExecutionController controller)
{
return limits.filter(UnfilteredPartitionIterators.filter(executeLocally(controller, false), nowInSec), nowInSec);
}
public UnfilteredPartitionIterator executeLocally(ReadExecutionController executionController)
{
return executeLocally(executionController, true);
}
/**
* Implementation of {@link ReadQuery#executeLocally(ReadExecutionController)}.
*
* @param executionController - the {@code ReadExecutionController} protecting the read.
* @param sort - whether to sort the inner commands by partition key, required for merging the iterator
* later on. This will be false when called by {@link ReadQuery#executeInternal(ReadExecutionController)}
* because in this case it is safe to do so as there is no merging involved and we don't want to
* change the old behavior which was to not sort by partition.
*
* @return - the iterator that can be used to retrieve the query result.
*/
private UnfilteredPartitionIterator executeLocally(ReadExecutionController executionController, boolean sort)
{
List> partitions = new ArrayList<>(commands.size());
for (SinglePartitionReadCommand cmd : commands)
partitions.add(Pair.of(cmd.partitionKey, cmd.executeLocally(executionController)));
if (sort)
Collections.sort(partitions, (p1, p2) -> p1.getLeft().compareTo(p2.getLeft()));
return UnfilteredPartitionIterators.concat(partitions.stream().map(p -> p.getRight()).collect(Collectors.toList()));
}
public QueryPager getPager(PagingState pagingState, ProtocolVersion protocolVersion)
{
if (commands.size() == 1)
return SinglePartitionReadCommand.getPager(commands.get(0), pagingState, protocolVersion);
return new MultiPartitionPager(this, pagingState, protocolVersion);
}
public boolean selectsKey(DecoratedKey key)
{
return Iterables.any(commands, c -> c.selectsKey(key));
}
public boolean selectsClustering(DecoratedKey key, Clustering clustering)
{
return Iterables.any(commands, c -> c.selectsClustering(key, clustering));
}
@Override
public String toString()
{
return commands.toString();
}
}
private static class Deserializer extends SelectionDeserializer
{
public ReadCommand deserialize(DataInputPlus in, int version, boolean isDigest, int digestVersion, boolean isForThrift, CFMetaData metadata, int nowInSec, ColumnFilter columnFilter, RowFilter rowFilter, DataLimits limits, Optional index)
throws IOException
{
DecoratedKey key = metadata.decorateKey(metadata.getKeyValidator().readValue(in, DatabaseDescriptor.getMaxValueSize()));
ClusteringIndexFilter filter = ClusteringIndexFilter.serializer.deserialize(in, version, metadata);
return new SinglePartitionReadCommand(isDigest, digestVersion, isForThrift, metadata, nowInSec, columnFilter, rowFilter, limits, key, filter);
}
}
/**
* {@code SSTableReaderListener} used to collect metrics about SSTable read access.
*/
private static final class SSTableReadMetricsCollector implements SSTableReadsListener
{
/**
* The number of SSTables that need to be merged. This counter is only updated for single partition queries
* since this has been the behavior so far.
*/
private int mergedSSTables;
@Override
public void onSSTableSelected(SSTableReader sstable, RowIndexEntry indexEntry, SelectionReason reason)
{
sstable.incrementReadCount();
mergedSSTables++;
}
/**
* Returns the number of SSTables that need to be merged.
* @return the number of SSTables that need to be merged.
*/
public int getMergedSSTables()
{
return mergedSSTables;
}
}
}