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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
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 * Unless required by applicable law or agreed to in writing, software
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package org.apache.cassandra.db;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.function.Predicate;

import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.cassandra.config.*;
import org.apache.cassandra.cql3.Operator;
import org.apache.cassandra.db.filter.*;
import org.apache.cassandra.db.monitoring.ApproximateTime;
import org.apache.cassandra.db.monitoring.MonitorableImpl;
import org.apache.cassandra.db.partitions.*;
import org.apache.cassandra.db.rows.*;
import org.apache.cassandra.db.transform.StoppingTransformation;
import org.apache.cassandra.db.transform.Transformation;
import org.apache.cassandra.dht.AbstractBounds;
import org.apache.cassandra.index.Index;
import org.apache.cassandra.index.IndexNotAvailableException;
import org.apache.cassandra.io.ForwardingVersionedSerializer;
import org.apache.cassandra.io.IVersionedSerializer;
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.schema.UnknownIndexException;
import org.apache.cassandra.service.ClientWarn;
import org.apache.cassandra.tracing.Tracing;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.Pair;

/**
 * General interface for storage-engine read commands (common to both range and
 * single partition commands).
 * 

* This contains all the informations needed to do a local read. */ public abstract class ReadCommand extends MonitorableImpl implements ReadQuery { private static final int TEST_ITERATION_DELAY_MILLIS = Integer.parseInt(System.getProperty("cassandra.test.read_iteration_delay_ms", "0")); protected static final Logger logger = LoggerFactory.getLogger(ReadCommand.class); public static final IVersionedSerializer serializer = new Serializer(); // For READ verb: will either dispatch on 'serializer' for 3.0 or 'legacyReadCommandSerializer' for earlier version. // Can be removed (and replaced by 'serializer') once we drop pre-3.0 backward compatibility. public static final IVersionedSerializer readSerializer = new ForwardingVersionedSerializer() { protected IVersionedSerializer delegate(int version) { return version < MessagingService.VERSION_30 ? legacyReadCommandSerializer : serializer; } }; // For RANGE_SLICE verb: will either dispatch on 'serializer' for 3.0 or 'legacyRangeSliceCommandSerializer' for earlier version. // Can be removed (and replaced by 'serializer') once we drop pre-3.0 backward compatibility. public static final IVersionedSerializer rangeSliceSerializer = new ForwardingVersionedSerializer() { protected IVersionedSerializer delegate(int version) { return version < MessagingService.VERSION_30 ? legacyRangeSliceCommandSerializer : serializer; } }; // For PAGED_RANGE verb: will either dispatch on 'serializer' for 3.0 or 'legacyPagedRangeCommandSerializer' for earlier version. // Can be removed (and replaced by 'serializer') once we drop pre-3.0 backward compatibility. public static final IVersionedSerializer pagedRangeSerializer = new ForwardingVersionedSerializer() { protected IVersionedSerializer delegate(int version) { return version < MessagingService.VERSION_30 ? legacyPagedRangeCommandSerializer : serializer; } }; public static final IVersionedSerializer legacyRangeSliceCommandSerializer = new LegacyRangeSliceCommandSerializer(); public static final IVersionedSerializer legacyPagedRangeCommandSerializer = new LegacyPagedRangeCommandSerializer(); public static final IVersionedSerializer legacyReadCommandSerializer = new LegacyReadCommandSerializer(); private final Kind kind; private final CFMetaData metadata; private final int nowInSec; private final ColumnFilter columnFilter; private final RowFilter rowFilter; private final DataLimits limits; // SecondaryIndexManager will attempt to provide the most selective of any available indexes // during execution. Here we also store an the results of that lookup to repeating it over // the lifetime of the command. protected Optional index = Optional.empty(); // Flag to indicate whether the index manager has been queried to select an index for this // command. This is necessary as the result of that lookup may be null, in which case we // still don't want to repeat it. private boolean indexManagerQueried = false; private boolean isDigestQuery; // if a digest query, the version for which the digest is expected. Ignored if not a digest. private int digestVersion; private final boolean isForThrift; protected static abstract class SelectionDeserializer { public abstract 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; } protected enum Kind { SINGLE_PARTITION (SinglePartitionReadCommand.selectionDeserializer), PARTITION_RANGE (PartitionRangeReadCommand.selectionDeserializer); private final SelectionDeserializer selectionDeserializer; Kind(SelectionDeserializer selectionDeserializer) { this.selectionDeserializer = selectionDeserializer; } } protected ReadCommand(Kind kind, boolean isDigestQuery, int digestVersion, boolean isForThrift, CFMetaData metadata, int nowInSec, ColumnFilter columnFilter, RowFilter rowFilter, DataLimits limits) { this.kind = kind; this.isDigestQuery = isDigestQuery; this.digestVersion = digestVersion; this.isForThrift = isForThrift; this.metadata = metadata; this.nowInSec = nowInSec; this.columnFilter = columnFilter; this.rowFilter = rowFilter; this.limits = limits; } protected abstract void serializeSelection(DataOutputPlus out, int version) throws IOException; protected abstract long selectionSerializedSize(int version); /** * Creates a new ReadCommand instance with new limits. * * @param newLimits the new limits * @return a new ReadCommand with the updated limits */ public abstract ReadCommand withUpdatedLimit(DataLimits newLimits); /** * The metadata for the table queried. * * @return the metadata for the table queried. */ public CFMetaData metadata() { return metadata; } /** * The time in seconds to use as "now" for this query. *

* We use the same time as "now" for the whole query to avoid considering different * values as expired during the query, which would be buggy (would throw of counting amongst other * things). * * @return the time (in seconds) to use as "now". */ public int nowInSec() { return nowInSec; } /** * The configured timeout for this command. * * @return the configured timeout for this command. */ public abstract long getTimeout(); /** * A filter on which (non-PK) columns must be returned by the query. * * @return which columns must be fetched by this query. */ public ColumnFilter columnFilter() { return columnFilter; } /** * Filters/Resrictions on CQL rows. *

* This contains the restrictions that are not directly handled by the * {@code ClusteringIndexFilter}. More specifically, this includes any non-PK column * restrictions and can include some PK columns restrictions when those can't be * satisfied entirely by the clustering index filter (because not all clustering columns * have been restricted for instance). If there is 2ndary indexes on the table, * one of this restriction might be handled by a 2ndary index. * * @return the filter holding the expression that rows must satisfy. */ public RowFilter rowFilter() { return rowFilter; } /** * The limits set on this query. * * @return the limits set on this query. */ public DataLimits limits() { return limits; } /** * Whether this query is a digest one or not. * * @return Whether this query is a digest query. */ public boolean isDigestQuery() { return isDigestQuery; } /** * If the query is a digest one, the requested digest version. * * @return the requested digest version if the query is a digest. Otherwise, this can return * anything. */ public int digestVersion() { return digestVersion; } /** * Sets whether this command should be a digest one or not. * * @param isDigestQuery whether the command should be set as a digest one or not. * @return this read command. */ public ReadCommand setIsDigestQuery(boolean isDigestQuery) { this.isDigestQuery = isDigestQuery; return this; } /** * Sets the digest version, for when digest for that command is requested. *

* Note that we allow setting this independently of setting the command as a digest query as * this allows us to use the command as a carrier of the digest version even if we only call * setIsDigestQuery on some copy of it. * * @param digestVersion the version for the digest is this command is used for digest query.. * @return this read command. */ public ReadCommand setDigestVersion(int digestVersion) { this.digestVersion = digestVersion; return this; } /** * Whether this query is for thrift or not. * * @return whether this query is for thrift. */ public boolean isForThrift() { return isForThrift; } /** * The clustering index filter this command to use for the provided key. *

* Note that that method should only be called on a key actually queried by this command * and in practice, this will almost always return the same filter, but for the sake of * paging, the filter on the first key of a range command might be slightly different. * * @param key a partition key queried by this command. * * @return the {@code ClusteringIndexFilter} to use for the partition of key {@code key}. */ public abstract ClusteringIndexFilter clusteringIndexFilter(DecoratedKey key); /** * Returns a copy of this command. * * @return a copy of this command. */ public abstract ReadCommand copy(); protected abstract UnfilteredPartitionIterator queryStorage(ColumnFamilyStore cfs, ReadExecutionController executionController); protected abstract int oldestUnrepairedTombstone(); public ReadResponse createResponse(UnfilteredPartitionIterator iterator) { return isDigestQuery() ? ReadResponse.createDigestResponse(iterator, this) : ReadResponse.createDataResponse(iterator, this); } public long indexSerializedSize(int version) { if (index.isPresent()) return IndexMetadata.serializer.serializedSize(index.get(), version); else return 0; } public Index getIndex(ColumnFamilyStore cfs) { // if we've already consulted the index manager, and it returned a valid index // the result should be cached here. if(index.isPresent()) return cfs.indexManager.getIndex(index.get()); // if no cached index is present, but we've already consulted the index manager // then no registered index is suitable for this command, so just return null. if (indexManagerQueried) return null; // do the lookup, set the flag to indicate so and cache the result if not null Index selected = cfs.indexManager.getBestIndexFor(this); indexManagerQueried = true; if (selected == null) return null; index = Optional.of(selected.getIndexMetadata()); return selected; } /** * If the index manager for the CFS determines that there's an applicable * 2i that can be used to execute this command, call its (optional) * validation method to check that nothing in this command's parameters * violates the implementation specific validation rules. */ public void maybeValidateIndex() { Index index = getIndex(Keyspace.openAndGetStore(metadata)); if (null != index) index.validate(this); } /** * Executes this command on the local host. * * @param executionController the execution controller spanning this command * * @return an iterator over the result of executing this command locally. */ @SuppressWarnings("resource") // The result iterator is closed upon exceptions (we know it's fine to potentially not close the intermediary // iterators created inside the try as long as we do close the original resultIterator), or by closing the result. public UnfilteredPartitionIterator executeLocally(ReadExecutionController executionController) { long startTimeNanos = System.nanoTime(); ColumnFamilyStore cfs = Keyspace.openAndGetStore(metadata()); Index index = getIndex(cfs); Index.Searcher searcher = null; if (index != null) { if (!cfs.indexManager.isIndexQueryable(index)) throw new IndexNotAvailableException(index); searcher = index.searcherFor(this); Tracing.trace("Executing read on {}.{} using index {}", cfs.metadata.ksName, cfs.metadata.cfName, index.getIndexMetadata().name); } UnfilteredPartitionIterator resultIterator = searcher == null ? queryStorage(cfs, executionController) : searcher.search(executionController); try { resultIterator = withStateTracking(resultIterator); resultIterator = withMetricsRecording(withoutPurgeableTombstones(resultIterator, cfs), cfs.metric, startTimeNanos); // If we've used a 2ndary index, we know the result already satisfy the primary expression used, so // no point in checking it again. RowFilter updatedFilter = searcher == null ? rowFilter() : index.getPostIndexQueryFilter(rowFilter()); // TODO: We'll currently do filtering by the rowFilter here because it's convenient. However, // we'll probably want to optimize by pushing it down the layer (like for dropped columns) as it // would be more efficient (the sooner we discard stuff we know we don't care, the less useless // processing we do on it). return limits().filter(updatedFilter.filter(resultIterator, nowInSec()), nowInSec()); } catch (RuntimeException | Error e) { resultIterator.close(); throw e; } } protected abstract void recordLatency(TableMetrics metric, long latencyNanos); public PartitionIterator executeInternal(ReadExecutionController controller) { return UnfilteredPartitionIterators.filter(executeLocally(controller), nowInSec()); } public ReadExecutionController executionController() { return ReadExecutionController.forCommand(this); } /** * Wraps the provided iterator so that metrics on what is scanned by the command are recorded. * This also log warning/trow TombstoneOverwhelmingException if appropriate. */ private UnfilteredPartitionIterator withMetricsRecording(UnfilteredPartitionIterator iter, final TableMetrics metric, final long startTimeNanos) { class MetricRecording extends Transformation { private final int failureThreshold = DatabaseDescriptor.getTombstoneFailureThreshold(); private final int warningThreshold = DatabaseDescriptor.getTombstoneWarnThreshold(); private final boolean respectTombstoneThresholds = !SchemaConstants.isSystemKeyspace(ReadCommand.this.metadata().ksName); private int liveRows = 0; private int tombstones = 0; private DecoratedKey currentKey; @Override public UnfilteredRowIterator applyToPartition(UnfilteredRowIterator iter) { currentKey = iter.partitionKey(); return Transformation.apply(iter, this); } @Override public Row applyToStatic(Row row) { return applyToRow(row); } @Override public Row applyToRow(Row row) { if (row.hasLiveData(ReadCommand.this.nowInSec())) ++liveRows; for (Cell cell : row.cells()) { if (!cell.isLive(ReadCommand.this.nowInSec())) countTombstone(row.clustering()); } return row; } @Override public RangeTombstoneMarker applyToMarker(RangeTombstoneMarker marker) { countTombstone(marker.clustering()); return marker; } private void countTombstone(ClusteringPrefix clustering) { ++tombstones; if (tombstones > failureThreshold && respectTombstoneThresholds) { String query = ReadCommand.this.toCQLString(); Tracing.trace("Scanned over {} tombstones for query {}; query aborted (see tombstone_failure_threshold)", failureThreshold, query); throw new TombstoneOverwhelmingException(tombstones, query, ReadCommand.this.metadata(), currentKey, clustering); } } @Override public void onClose() { recordLatency(metric, System.nanoTime() - startTimeNanos); metric.tombstoneScannedHistogram.update(tombstones); metric.liveScannedHistogram.update(liveRows); boolean warnTombstones = tombstones > warningThreshold && respectTombstoneThresholds; if (warnTombstones) { String msg = String.format("Read %d live rows and %d tombstone cells for query %1.512s (see tombstone_warn_threshold)", liveRows, tombstones, ReadCommand.this.toCQLString()); ClientWarn.instance.warn(msg); logger.warn(msg); } Tracing.trace("Read {} live and {} tombstone cells{}", liveRows, tombstones, (warnTombstones ? " (see tombstone_warn_threshold)" : "")); } }; return Transformation.apply(iter, new MetricRecording()); } protected class CheckForAbort extends StoppingTransformation { long lastChecked = 0; protected UnfilteredRowIterator applyToPartition(UnfilteredRowIterator partition) { if (maybeAbort()) { partition.close(); return null; } return Transformation.apply(partition, this); } protected Row applyToRow(Row row) { if (TEST_ITERATION_DELAY_MILLIS > 0) maybeDelayForTesting(); return maybeAbort() ? null : row; } private boolean maybeAbort() { /** * The value returned by ApproximateTime.currentTimeMillis() is updated only every * {@link ApproximateTime.CHECK_INTERVAL_MS}, by default 10 millis. Since MonitorableImpl * relies on ApproximateTime, we don't need to check unless the approximate time has elapsed. */ if (lastChecked == ApproximateTime.currentTimeMillis()) return false; lastChecked = ApproximateTime.currentTimeMillis(); if (isAborted()) { stop(); return true; } return false; } private void maybeDelayForTesting() { if (!metadata.ksName.startsWith("system")) FBUtilities.sleepQuietly(TEST_ITERATION_DELAY_MILLIS); } } protected UnfilteredPartitionIterator withStateTracking(UnfilteredPartitionIterator iter) { return Transformation.apply(iter, new CheckForAbort()); } /** * Creates a message for this command. */ public abstract MessageOut createMessage(int version); protected abstract void appendCQLWhereClause(StringBuilder sb); // Skip purgeable tombstones. We do this because it's safe to do (post-merge of the memtable and sstable at least), it // can save us some bandwith, and avoid making us throw a TombstoneOverwhelmingException for purgeable tombstones (which // are to some extend an artefact of compaction lagging behind and hence counting them is somewhat unintuitive). protected UnfilteredPartitionIterator withoutPurgeableTombstones(UnfilteredPartitionIterator iterator, ColumnFamilyStore cfs) { final boolean isForThrift = iterator.isForThrift(); class WithoutPurgeableTombstones extends PurgeFunction { public WithoutPurgeableTombstones() { super(isForThrift, nowInSec(), cfs.gcBefore(nowInSec()), oldestUnrepairedTombstone(), cfs.getCompactionStrategyManager().onlyPurgeRepairedTombstones()); } protected Predicate getPurgeEvaluator() { return time -> true; } } return Transformation.apply(iterator, new WithoutPurgeableTombstones()); } /** * Recreate the CQL string corresponding to this query. *

* Note that in general the returned string will not be exactly the original user string, first * because there isn't always a single syntax for a given query, but also because we don't have * all the information needed (we know the non-PK columns queried but not the PK ones as internally * we query them all). So this shouldn't be relied too strongly, but this should be good enough for * debugging purpose which is what this is for. */ public String toCQLString() { StringBuilder sb = new StringBuilder(); sb.append("SELECT ").append(columnFilter()); sb.append(" FROM ").append(metadata().ksName).append('.').append(metadata.cfName); appendCQLWhereClause(sb); if (limits() != DataLimits.NONE) sb.append(' ').append(limits()); return sb.toString(); } // Monitorable interface public String name() { return toCQLString(); } private static class Serializer implements IVersionedSerializer { private static int digestFlag(boolean isDigest) { return isDigest ? 0x01 : 0; } private static boolean isDigest(int flags) { return (flags & 0x01) != 0; } private static int thriftFlag(boolean isForThrift) { return isForThrift ? 0x02 : 0; } private static boolean isForThrift(int flags) { return (flags & 0x02) != 0; } private static int indexFlag(boolean hasIndex) { return hasIndex ? 0x04 : 0; } private static boolean hasIndex(int flags) { return (flags & 0x04) != 0; } public void serialize(ReadCommand command, DataOutputPlus out, int version) throws IOException { assert version >= MessagingService.VERSION_30; out.writeByte(command.kind.ordinal()); out.writeByte(digestFlag(command.isDigestQuery()) | thriftFlag(command.isForThrift()) | indexFlag(command.index.isPresent())); if (command.isDigestQuery()) out.writeUnsignedVInt(command.digestVersion()); CFMetaData.serializer.serialize(command.metadata(), out, version); out.writeInt(command.nowInSec()); ColumnFilter.serializer.serialize(command.columnFilter(), out, version); RowFilter.serializer.serialize(command.rowFilter(), out, version); DataLimits.serializer.serialize(command.limits(), out, version, command.metadata.comparator); if (command.index.isPresent()) IndexMetadata.serializer.serialize(command.index.get(), out, version); command.serializeSelection(out, version); } public ReadCommand deserialize(DataInputPlus in, int version) throws IOException { assert version >= MessagingService.VERSION_30; Kind kind = Kind.values()[in.readByte()]; int flags = in.readByte(); boolean isDigest = isDigest(flags); boolean isForThrift = isForThrift(flags); boolean hasIndex = hasIndex(flags); int digestVersion = isDigest ? (int)in.readUnsignedVInt() : 0; CFMetaData metadata = CFMetaData.serializer.deserialize(in, version); int nowInSec = in.readInt(); ColumnFilter columnFilter = ColumnFilter.serializer.deserialize(in, version, metadata); RowFilter rowFilter = RowFilter.serializer.deserialize(in, version, metadata); DataLimits limits = DataLimits.serializer.deserialize(in, version, metadata.comparator); Optional index = hasIndex ? deserializeIndexMetadata(in, version, metadata) : Optional.empty(); return kind.selectionDeserializer.deserialize(in, version, isDigest, digestVersion, isForThrift, metadata, nowInSec, columnFilter, rowFilter, limits, index); } private Optional deserializeIndexMetadata(DataInputPlus in, int version, CFMetaData cfm) throws IOException { try { return Optional.of(IndexMetadata.serializer.deserialize(in, version, cfm)); } catch (UnknownIndexException e) { logger.info("Couldn't find a defined index on {}.{} with the id {}. " + "If an index was just created, this is likely due to the schema not " + "being fully propagated. Local read will proceed without using the " + "index. Please wait for schema agreement after index creation.", cfm.ksName, cfm.cfName, e.indexId); return Optional.empty(); } } public long serializedSize(ReadCommand command, int version) { assert version >= MessagingService.VERSION_30; return 2 // kind + flags + (command.isDigestQuery() ? TypeSizes.sizeofUnsignedVInt(command.digestVersion()) : 0) + CFMetaData.serializer.serializedSize(command.metadata(), version) + TypeSizes.sizeof(command.nowInSec()) + ColumnFilter.serializer.serializedSize(command.columnFilter(), version) + RowFilter.serializer.serializedSize(command.rowFilter(), version) + DataLimits.serializer.serializedSize(command.limits(), version, command.metadata.comparator) + command.selectionSerializedSize(version) + command.indexSerializedSize(version); } } private enum LegacyType { GET_BY_NAMES((byte)1), GET_SLICES((byte)2); public final byte serializedValue; LegacyType(byte b) { this.serializedValue = b; } public static LegacyType fromPartitionFilterKind(ClusteringIndexFilter.Kind kind) { return kind == ClusteringIndexFilter.Kind.SLICE ? GET_SLICES : GET_BY_NAMES; } public static LegacyType fromSerializedValue(byte b) { return b == 1 ? GET_BY_NAMES : GET_SLICES; } } /** * Serializer for pre-3.0 RangeSliceCommands. */ private static class LegacyRangeSliceCommandSerializer implements IVersionedSerializer { public void serialize(ReadCommand command, DataOutputPlus out, int version) throws IOException { assert version < MessagingService.VERSION_30; PartitionRangeReadCommand rangeCommand = (PartitionRangeReadCommand) command; assert !rangeCommand.dataRange().isPaging(); // convert pre-3.0 incompatible names filters to slice filters rangeCommand = maybeConvertNamesToSlice(rangeCommand); CFMetaData metadata = rangeCommand.metadata(); out.writeUTF(metadata.ksName); out.writeUTF(metadata.cfName); out.writeLong(rangeCommand.nowInSec() * 1000L); // convert from seconds to millis // begin DiskAtomFilterSerializer.serialize() if (rangeCommand.isNamesQuery()) { out.writeByte(1); // 0 for slices, 1 for names ClusteringIndexNamesFilter filter = (ClusteringIndexNamesFilter) rangeCommand.dataRange().clusteringIndexFilter; LegacyReadCommandSerializer.serializeNamesFilter(rangeCommand, filter, out); } else { out.writeByte(0); // 0 for slices, 1 for names // slice filter serialization ClusteringIndexSliceFilter filter = (ClusteringIndexSliceFilter) rangeCommand.dataRange().clusteringIndexFilter; boolean makeStaticSlice = !rangeCommand.columnFilter().fetchedColumns().statics.isEmpty() && !filter.requestedSlices().selects(Clustering.STATIC_CLUSTERING); LegacyReadCommandSerializer.serializeSlices(out, filter.requestedSlices(), filter.isReversed(), makeStaticSlice, metadata); out.writeBoolean(filter.isReversed()); // limit DataLimits limits = rangeCommand.limits(); if (limits.isDistinct()) out.writeInt(1); else out.writeInt(LegacyReadCommandSerializer.updateLimitForQuery(rangeCommand.limits().count(), filter.requestedSlices())); int compositesToGroup; boolean selectsStatics = !rangeCommand.columnFilter().fetchedColumns().statics.isEmpty() && filter.requestedSlices().selects(Clustering.STATIC_CLUSTERING); if (limits.kind() == DataLimits.Kind.THRIFT_LIMIT) compositesToGroup = -1; else if (limits.isDistinct() && !selectsStatics) compositesToGroup = -2; // for DISTINCT queries (CASSANDRA-8490) else compositesToGroup = metadata.isDense() ? -1 : metadata.clusteringColumns().size(); out.writeInt(compositesToGroup); } serializeRowFilter(out, rangeCommand.rowFilter()); AbstractBounds.rowPositionSerializer.serialize(rangeCommand.dataRange().keyRange(), out, version); // maxResults out.writeInt(rangeCommand.limits().count()); // countCQL3Rows if (rangeCommand.isForThrift() || rangeCommand.limits().perPartitionCount() == 1) // if for Thrift or DISTINCT out.writeBoolean(false); else out.writeBoolean(true); // isPaging out.writeBoolean(false); } public ReadCommand deserialize(DataInputPlus in, int version) throws IOException { assert version < MessagingService.VERSION_30; String keyspace = in.readUTF(); String columnFamily = in.readUTF(); CFMetaData metadata = Schema.instance.getCFMetaData(keyspace, columnFamily); if (metadata == null) { String message = String.format("Got legacy range command for nonexistent table %s.%s.", keyspace, columnFamily); throw new UnknownColumnFamilyException(message, null); } int nowInSec = (int) (in.readLong() / 1000); // convert from millis to seconds ClusteringIndexFilter filter; ColumnFilter selection; int compositesToGroup = 0; int perPartitionLimit = -1; byte readType = in.readByte(); // 0 for slices, 1 for names if (readType == 1) { Pair selectionAndFilter = LegacyReadCommandSerializer.deserializeNamesSelectionAndFilter(in, metadata); selection = selectionAndFilter.left; filter = selectionAndFilter.right; } else { Pair p = LegacyReadCommandSerializer.deserializeSlicePartitionFilter(in, metadata); filter = p.left; perPartitionLimit = in.readInt(); compositesToGroup = in.readInt(); selection = getColumnSelectionForSlice(p.right, compositesToGroup, metadata); } RowFilter rowFilter = deserializeRowFilter(in, metadata); AbstractBounds keyRange = AbstractBounds.rowPositionSerializer.deserialize(in, metadata.partitioner, version); int maxResults = in.readInt(); boolean countCQL3Rows = in.readBoolean(); // countCQL3Rows (not needed) in.readBoolean(); // isPaging (not needed) boolean selectsStatics = (!selection.fetchedColumns().statics.isEmpty() || filter.selects(Clustering.STATIC_CLUSTERING)); // We have 2 types of DISTINCT queries: ones on only the partition key, and ones on the partition key and static columns. For the former, // we can easily detect the case because compositeToGroup is -2 and that's the only case it can be that. The latter one is slightly less // direct, but we know that on 2.1/2.2 queries, DISTINCT queries are the only CQL queries that have countCQL3Rows to false so we use // that fact. boolean isDistinct = compositesToGroup == -2 || (compositesToGroup != -1 && !countCQL3Rows); DataLimits limits; if (isDistinct) limits = DataLimits.distinctLimits(maxResults); else if (compositesToGroup == -1) limits = DataLimits.thriftLimits(maxResults, perPartitionLimit); else limits = DataLimits.cqlLimits(maxResults); return new PartitionRangeReadCommand(false, 0, true, metadata, nowInSec, selection, rowFilter, limits, new DataRange(keyRange, filter), Optional.empty()); } static void serializeRowFilter(DataOutputPlus out, RowFilter rowFilter) throws IOException { ArrayList indexExpressions = Lists.newArrayList(rowFilter.iterator()); out.writeInt(indexExpressions.size()); for (RowFilter.Expression expression : indexExpressions) { ByteBufferUtil.writeWithShortLength(expression.column().name.bytes, out); expression.operator().writeTo(out); ByteBufferUtil.writeWithShortLength(expression.getIndexValue(), out); } } static RowFilter deserializeRowFilter(DataInputPlus in, CFMetaData metadata) throws IOException { int numRowFilters = in.readInt(); if (numRowFilters == 0) return RowFilter.NONE; RowFilter rowFilter = RowFilter.create(numRowFilters); for (int i = 0; i < numRowFilters; i++) { ByteBuffer columnName = ByteBufferUtil.readWithShortLength(in); ColumnDefinition column = metadata.getColumnDefinition(columnName); Operator op = Operator.readFrom(in); ByteBuffer indexValue = ByteBufferUtil.readWithShortLength(in); rowFilter.add(column, op, indexValue); } return rowFilter; } static long serializedRowFilterSize(RowFilter rowFilter) { long size = TypeSizes.sizeof(0); // rowFilterCount for (RowFilter.Expression expression : rowFilter) { size += ByteBufferUtil.serializedSizeWithShortLength(expression.column().name.bytes); size += TypeSizes.sizeof(0); // operator int value size += ByteBufferUtil.serializedSizeWithShortLength(expression.getIndexValue()); } return size; } public long serializedSize(ReadCommand command, int version) { assert version < MessagingService.VERSION_30; assert command.kind == Kind.PARTITION_RANGE; PartitionRangeReadCommand rangeCommand = (PartitionRangeReadCommand) command; rangeCommand = maybeConvertNamesToSlice(rangeCommand); CFMetaData metadata = rangeCommand.metadata(); long size = TypeSizes.sizeof(metadata.ksName); size += TypeSizes.sizeof(metadata.cfName); size += TypeSizes.sizeof((long) rangeCommand.nowInSec()); size += 1; // single byte flag: 0 for slices, 1 for names if (rangeCommand.isNamesQuery()) { PartitionColumns columns = rangeCommand.columnFilter().fetchedColumns(); ClusteringIndexNamesFilter filter = (ClusteringIndexNamesFilter) rangeCommand.dataRange().clusteringIndexFilter; size += LegacyReadCommandSerializer.serializedNamesFilterSize(filter, metadata, columns); } else { ClusteringIndexSliceFilter filter = (ClusteringIndexSliceFilter) rangeCommand.dataRange().clusteringIndexFilter; boolean makeStaticSlice = !rangeCommand.columnFilter().fetchedColumns().statics.isEmpty() && !filter.requestedSlices().selects(Clustering.STATIC_CLUSTERING); size += LegacyReadCommandSerializer.serializedSlicesSize(filter.requestedSlices(), makeStaticSlice, metadata); size += TypeSizes.sizeof(filter.isReversed()); size += TypeSizes.sizeof(rangeCommand.limits().perPartitionCount()); size += TypeSizes.sizeof(0); // compositesToGroup } if (rangeCommand.rowFilter().equals(RowFilter.NONE)) { size += TypeSizes.sizeof(0); } else { ArrayList indexExpressions = Lists.newArrayList(rangeCommand.rowFilter().iterator()); size += TypeSizes.sizeof(indexExpressions.size()); for (RowFilter.Expression expression : indexExpressions) { size += ByteBufferUtil.serializedSizeWithShortLength(expression.column().name.bytes); size += TypeSizes.sizeof(expression.operator().ordinal()); size += ByteBufferUtil.serializedSizeWithShortLength(expression.getIndexValue()); } } size += AbstractBounds.rowPositionSerializer.serializedSize(rangeCommand.dataRange().keyRange(), version); size += TypeSizes.sizeof(rangeCommand.limits().count()); size += TypeSizes.sizeof(!rangeCommand.isForThrift()); return size + TypeSizes.sizeof(rangeCommand.dataRange().isPaging()); } static PartitionRangeReadCommand maybeConvertNamesToSlice(PartitionRangeReadCommand command) { if (!command.dataRange().isNamesQuery()) return command; CFMetaData metadata = command.metadata(); if (!LegacyReadCommandSerializer.shouldConvertNamesToSlice(metadata, command.columnFilter().fetchedColumns())) return command; ClusteringIndexNamesFilter filter = (ClusteringIndexNamesFilter) command.dataRange().clusteringIndexFilter; ClusteringIndexSliceFilter sliceFilter = LegacyReadCommandSerializer.convertNamesFilterToSliceFilter(filter, metadata); DataRange newRange = new DataRange(command.dataRange().keyRange(), sliceFilter); return new PartitionRangeReadCommand( command.isDigestQuery(), command.digestVersion(), command.isForThrift(), metadata, command.nowInSec(), command.columnFilter(), command.rowFilter(), command.limits(), newRange, Optional.empty()); } static ColumnFilter getColumnSelectionForSlice(boolean selectsStatics, int compositesToGroup, CFMetaData metadata) { // A value of -2 indicates this is a DISTINCT query that doesn't select static columns, only partition keys. // In that case, we'll basically be querying the first row of the partition, but we must make sure we include // all columns so we get at least one cell if there is a live row as it would confuse pre-3.0 nodes otherwise. if (compositesToGroup == -2) return ColumnFilter.all(metadata); // if a slice query from a pre-3.0 node doesn't cover statics, we shouldn't select them at all PartitionColumns columns = selectsStatics ? metadata.partitionColumns() : metadata.partitionColumns().withoutStatics(); return ColumnFilter.selectionBuilder().addAll(columns).build(); } } /** * Serializer for pre-3.0 PagedRangeCommands. */ private static class LegacyPagedRangeCommandSerializer implements IVersionedSerializer { public void serialize(ReadCommand command, DataOutputPlus out, int version) throws IOException { assert version < MessagingService.VERSION_30; PartitionRangeReadCommand rangeCommand = (PartitionRangeReadCommand) command; assert rangeCommand.dataRange().isPaging(); CFMetaData metadata = rangeCommand.metadata(); out.writeUTF(metadata.ksName); out.writeUTF(metadata.cfName); out.writeLong(rangeCommand.nowInSec() * 1000L); // convert from seconds to millis AbstractBounds.rowPositionSerializer.serialize(rangeCommand.dataRange().keyRange(), out, version); // pre-3.0 nodes don't accept names filters for paged range commands ClusteringIndexSliceFilter filter; if (rangeCommand.dataRange().clusteringIndexFilter.kind() == ClusteringIndexFilter.Kind.NAMES) filter = LegacyReadCommandSerializer.convertNamesFilterToSliceFilter((ClusteringIndexNamesFilter) rangeCommand.dataRange().clusteringIndexFilter, metadata); else filter = (ClusteringIndexSliceFilter) rangeCommand.dataRange().clusteringIndexFilter; // slice filter boolean makeStaticSlice = !rangeCommand.columnFilter().fetchedColumns().statics.isEmpty() && !filter.requestedSlices().selects(Clustering.STATIC_CLUSTERING); LegacyReadCommandSerializer.serializeSlices(out, filter.requestedSlices(), filter.isReversed(), makeStaticSlice, metadata); out.writeBoolean(filter.isReversed()); // slice filter's count DataLimits.Kind kind = rangeCommand.limits().kind(); boolean isDistinct = (kind == DataLimits.Kind.CQL_LIMIT || kind == DataLimits.Kind.CQL_PAGING_LIMIT) && rangeCommand.limits().perPartitionCount() == 1; if (isDistinct) out.writeInt(1); else out.writeInt(LegacyReadCommandSerializer.updateLimitForQuery(rangeCommand.limits().perPartitionCount(), filter.requestedSlices())); // compositesToGroup boolean selectsStatics = !rangeCommand.columnFilter().fetchedColumns().statics.isEmpty() || filter.requestedSlices().selects(Clustering.STATIC_CLUSTERING); int compositesToGroup; if (kind == DataLimits.Kind.THRIFT_LIMIT) compositesToGroup = -1; else if (isDistinct && !selectsStatics) compositesToGroup = -2; // for DISTINCT queries (CASSANDRA-8490) else compositesToGroup = metadata.isDense() ? -1 : metadata.clusteringColumns().size(); out.writeInt(compositesToGroup); // command-level "start" and "stop" composites. The start is the last-returned cell name if there is one, // otherwise it's the same as the slice filter's start. The stop appears to always be the same as the // slice filter's stop. DataRange.Paging pagingRange = (DataRange.Paging) rangeCommand.dataRange(); Clustering lastReturned = pagingRange.getLastReturned(); ClusteringBound newStart = ClusteringBound.inclusiveStartOf(lastReturned); Slice lastSlice = filter.requestedSlices().get(filter.requestedSlices().size() - 1); ByteBufferUtil.writeWithShortLength(LegacyLayout.encodeBound(metadata, newStart, true), out); ByteBufferUtil.writeWithShortLength(LegacyLayout.encodeClustering(metadata, lastSlice.end().clustering()), out); LegacyRangeSliceCommandSerializer.serializeRowFilter(out, rangeCommand.rowFilter()); // command-level limit // Pre-3.0 we would always request one more row than we actually needed and the command-level "start" would // be the last-returned cell name, so the response would always include it. int maxResults = rangeCommand.limits().count() + 1; out.writeInt(maxResults); // countCQL3Rows if (rangeCommand.isForThrift() || rangeCommand.limits().perPartitionCount() == 1) // for Thrift or DISTINCT out.writeBoolean(false); else out.writeBoolean(true); } public ReadCommand deserialize(DataInputPlus in, int version) throws IOException { assert version < MessagingService.VERSION_30; String keyspace = in.readUTF(); String columnFamily = in.readUTF(); CFMetaData metadata = Schema.instance.getCFMetaData(keyspace, columnFamily); if (metadata == null) { String message = String.format("Got legacy paged range command for nonexistent table %s.%s.", keyspace, columnFamily); throw new UnknownColumnFamilyException(message, null); } int nowInSec = (int) (in.readLong() / 1000); // convert from millis to seconds AbstractBounds keyRange = AbstractBounds.rowPositionSerializer.deserialize(in, metadata.partitioner, version); Pair p = LegacyReadCommandSerializer.deserializeSlicePartitionFilter(in, metadata); ClusteringIndexSliceFilter filter = p.left; boolean selectsStatics = p.right; int perPartitionLimit = in.readInt(); int compositesToGroup = in.readInt(); // command-level Composite "start" and "stop" LegacyLayout.LegacyBound startBound = LegacyLayout.decodeBound(metadata, ByteBufferUtil.readWithShortLength(in), true); ByteBufferUtil.readWithShortLength(in); // the composite "stop", which isn't actually needed ColumnFilter selection = LegacyRangeSliceCommandSerializer.getColumnSelectionForSlice(selectsStatics, compositesToGroup, metadata); RowFilter rowFilter = LegacyRangeSliceCommandSerializer.deserializeRowFilter(in, metadata); int maxResults = in.readInt(); boolean countCQL3Rows = in.readBoolean(); // We have 2 types of DISTINCT queries: ones on only the partition key, and ones on the partition key and static columns. For the former, // we can easily detect the case because compositeToGroup is -2 and that's the only case it can be that. The latter one is slightly less // direct, but we know that on 2.1/2.2 queries, DISTINCT queries are the only CQL queries that have countCQL3Rows to false so we use // that fact. boolean isDistinct = compositesToGroup == -2 || (compositesToGroup != -1 && !countCQL3Rows); DataLimits limits; if (isDistinct) limits = DataLimits.distinctLimits(maxResults); else limits = DataLimits.cqlLimits(maxResults); limits = limits.forPaging(maxResults); // The pagedRangeCommand is used in pre-3.0 for both the first page and the following ones. On the first page, the startBound will be // the start of the overall slice and will not be a proper Clustering. So detect that case and just return a non-paging DataRange, which // is what 3.0 does. DataRange dataRange = new DataRange(keyRange, filter); Slices slices = filter.requestedSlices(); if (!isDistinct && startBound != LegacyLayout.LegacyBound.BOTTOM && !startBound.bound.equals(slices.get(0).start())) { // pre-3.0 nodes normally expect pages to include the last cell from the previous page, but they handle it // missing without any problems, so we can safely always set "inclusive" to false in the data range dataRange = dataRange.forPaging(keyRange, metadata.comparator, startBound.getAsClustering(metadata), false); } return new PartitionRangeReadCommand(false, 0, true, metadata, nowInSec, selection, rowFilter, limits, dataRange, Optional.empty()); } public long serializedSize(ReadCommand command, int version) { assert version < MessagingService.VERSION_30; assert command.kind == Kind.PARTITION_RANGE; PartitionRangeReadCommand rangeCommand = (PartitionRangeReadCommand) command; CFMetaData metadata = rangeCommand.metadata(); assert rangeCommand.dataRange().isPaging(); long size = TypeSizes.sizeof(metadata.ksName); size += TypeSizes.sizeof(metadata.cfName); size += TypeSizes.sizeof((long) rangeCommand.nowInSec()); size += AbstractBounds.rowPositionSerializer.serializedSize(rangeCommand.dataRange().keyRange(), version); // pre-3.0 nodes only accept slice filters for paged range commands ClusteringIndexSliceFilter filter; if (rangeCommand.dataRange().clusteringIndexFilter.kind() == ClusteringIndexFilter.Kind.NAMES) filter = LegacyReadCommandSerializer.convertNamesFilterToSliceFilter((ClusteringIndexNamesFilter) rangeCommand.dataRange().clusteringIndexFilter, metadata); else filter = (ClusteringIndexSliceFilter) rangeCommand.dataRange().clusteringIndexFilter; // slice filter boolean makeStaticSlice = !rangeCommand.columnFilter().fetchedColumns().statics.isEmpty() && !filter.requestedSlices().selects(Clustering.STATIC_CLUSTERING); size += LegacyReadCommandSerializer.serializedSlicesSize(filter.requestedSlices(), makeStaticSlice, metadata); size += TypeSizes.sizeof(filter.isReversed()); // slice filter's count size += TypeSizes.sizeof(rangeCommand.limits().perPartitionCount()); // compositesToGroup size += TypeSizes.sizeof(0); // command-level Composite "start" and "stop" DataRange.Paging pagingRange = (DataRange.Paging) rangeCommand.dataRange(); Clustering lastReturned = pagingRange.getLastReturned(); Slice lastSlice = filter.requestedSlices().get(filter.requestedSlices().size() - 1); size += ByteBufferUtil.serializedSizeWithShortLength(LegacyLayout.encodeClustering(metadata, lastReturned)); size += ByteBufferUtil.serializedSizeWithShortLength(LegacyLayout.encodeClustering(metadata, lastSlice.end().clustering())); size += LegacyRangeSliceCommandSerializer.serializedRowFilterSize(rangeCommand.rowFilter()); // command-level limit size += TypeSizes.sizeof(rangeCommand.limits().count()); // countCQL3Rows return size + TypeSizes.sizeof(true); } } /** * Serializer for pre-3.0 ReadCommands. */ static class LegacyReadCommandSerializer implements IVersionedSerializer { public void serialize(ReadCommand command, DataOutputPlus out, int version) throws IOException { assert version < MessagingService.VERSION_30; assert command.kind == Kind.SINGLE_PARTITION; SinglePartitionReadCommand singleReadCommand = (SinglePartitionReadCommand) command; singleReadCommand = maybeConvertNamesToSlice(singleReadCommand); CFMetaData metadata = singleReadCommand.metadata(); out.writeByte(LegacyType.fromPartitionFilterKind(singleReadCommand.clusteringIndexFilter().kind()).serializedValue); out.writeBoolean(singleReadCommand.isDigestQuery()); out.writeUTF(metadata.ksName); ByteBufferUtil.writeWithShortLength(singleReadCommand.partitionKey().getKey(), out); out.writeUTF(metadata.cfName); out.writeLong(singleReadCommand.nowInSec() * 1000L); // convert from seconds to millis if (singleReadCommand.clusteringIndexFilter().kind() == ClusteringIndexFilter.Kind.SLICE) serializeSliceCommand(singleReadCommand, out); else serializeNamesCommand(singleReadCommand, out); } public ReadCommand deserialize(DataInputPlus in, int version) throws IOException { assert version < MessagingService.VERSION_30; LegacyType msgType = LegacyType.fromSerializedValue(in.readByte()); boolean isDigest = in.readBoolean(); String keyspaceName = in.readUTF(); ByteBuffer key = ByteBufferUtil.readWithShortLength(in); String cfName = in.readUTF(); long nowInMillis = in.readLong(); int nowInSeconds = (int) (nowInMillis / 1000); // convert from millis to seconds CFMetaData metadata = Schema.instance.getCFMetaData(keyspaceName, cfName); DecoratedKey dk = metadata.partitioner.decorateKey(key); switch (msgType) { case GET_BY_NAMES: return deserializeNamesCommand(in, isDigest, metadata, dk, nowInSeconds, version); case GET_SLICES: return deserializeSliceCommand(in, isDigest, metadata, dk, nowInSeconds, version); default: throw new AssertionError(); } } public long serializedSize(ReadCommand command, int version) { assert version < MessagingService.VERSION_30; assert command.kind == Kind.SINGLE_PARTITION; SinglePartitionReadCommand singleReadCommand = (SinglePartitionReadCommand) command; singleReadCommand = maybeConvertNamesToSlice(singleReadCommand); int keySize = singleReadCommand.partitionKey().getKey().remaining(); CFMetaData metadata = singleReadCommand.metadata(); long size = 1; // message type (single byte) size += TypeSizes.sizeof(command.isDigestQuery()); size += TypeSizes.sizeof(metadata.ksName); size += TypeSizes.sizeof((short) keySize) + keySize; size += TypeSizes.sizeof((long) command.nowInSec()); if (singleReadCommand.clusteringIndexFilter().kind() == ClusteringIndexFilter.Kind.SLICE) return size + serializedSliceCommandSize(singleReadCommand); else return size + serializedNamesCommandSize(singleReadCommand); } private void serializeNamesCommand(SinglePartitionReadCommand command, DataOutputPlus out) throws IOException { serializeNamesFilter(command, (ClusteringIndexNamesFilter)command.clusteringIndexFilter(), out); } private static void serializeNamesFilter(ReadCommand command, ClusteringIndexNamesFilter filter, DataOutputPlus out) throws IOException { PartitionColumns columns = command.columnFilter().fetchedColumns(); CFMetaData metadata = command.metadata(); SortedSet requestedRows = filter.requestedRows(); if (requestedRows.isEmpty()) { // only static columns are requested out.writeInt(columns.size()); for (ColumnDefinition column : columns) ByteBufferUtil.writeWithShortLength(column.name.bytes, out); } else { out.writeInt(requestedRows.size() * columns.size()); for (Clustering clustering : requestedRows) { for (ColumnDefinition column : columns) ByteBufferUtil.writeWithShortLength(LegacyLayout.encodeCellName(metadata, clustering, column.name.bytes, null), out); } } // countCql3Rows should be true if it's not for Thrift or a DISTINCT query if (command.isForThrift() || (command.limits().kind() == DataLimits.Kind.CQL_LIMIT && command.limits().perPartitionCount() == 1)) out.writeBoolean(false); // it's compact and not a DISTINCT query else out.writeBoolean(true); } static long serializedNamesFilterSize(ClusteringIndexNamesFilter filter, CFMetaData metadata, PartitionColumns fetchedColumns) { SortedSet requestedRows = filter.requestedRows(); long size = 0; if (requestedRows.isEmpty()) { // only static columns are requested size += TypeSizes.sizeof(fetchedColumns.size()); for (ColumnDefinition column : fetchedColumns) size += ByteBufferUtil.serializedSizeWithShortLength(column.name.bytes); } else { size += TypeSizes.sizeof(requestedRows.size() * fetchedColumns.size()); for (Clustering clustering : requestedRows) { for (ColumnDefinition column : fetchedColumns) size += ByteBufferUtil.serializedSizeWithShortLength(LegacyLayout.encodeCellName(metadata, clustering, column.name.bytes, null)); } } return size + TypeSizes.sizeof(true); // countCql3Rows } private SinglePartitionReadCommand deserializeNamesCommand(DataInputPlus in, boolean isDigest, CFMetaData metadata, DecoratedKey key, int nowInSeconds, int version) throws IOException { Pair selectionAndFilter = deserializeNamesSelectionAndFilter(in, metadata); // messages from old nodes will expect the thrift format, so always use 'true' for isForThrift return new SinglePartitionReadCommand( isDigest, version, true, metadata, nowInSeconds, selectionAndFilter.left, RowFilter.NONE, DataLimits.NONE, key, selectionAndFilter.right); } static Pair deserializeNamesSelectionAndFilter(DataInputPlus in, CFMetaData metadata) throws IOException { int numCellNames = in.readInt(); // The names filter could include either a) static columns or b) normal columns with the clustering columns // fully specified. We need to handle those cases differently in 3.0. NavigableSet clusterings = new TreeSet<>(metadata.comparator); ColumnFilter.Builder selectionBuilder = ColumnFilter.selectionBuilder(); for (int i = 0; i < numCellNames; i++) { ByteBuffer buffer = ByteBufferUtil.readWithShortLength(in); LegacyLayout.LegacyCellName cellName; try { cellName = LegacyLayout.decodeCellName(metadata, buffer); } catch (UnknownColumnException exc) { // TODO this probably needs a new exception class that shares a parent with UnknownColumnFamilyException throw new UnknownColumnFamilyException( "Received legacy range read command with names filter for unrecognized column name. " + "Fill name in filter (hex): " + ByteBufferUtil.bytesToHex(buffer), metadata.cfId); } // If we're querying for a static column, we may also need to read it // as if it were a thrift dynamic column (because the column metadata, // which makes it a static column in 3.0+, may have been added *after* // some values were written). Note that all cql queries on non-compact // tables used slice & not name filters prior to 3.0 so this path is // not taken for non-compact tables. It is theoretically possible to // get here via thrift, hence the check on metadata.isStaticCompactTable. // See CASSANDRA-11087. if (metadata.isStaticCompactTable() && cellName.clustering.equals(Clustering.STATIC_CLUSTERING)) { clusterings.add(Clustering.make(cellName.column.name.bytes)); selectionBuilder.add(metadata.compactValueColumn()); } else { clusterings.add(cellName.clustering); } selectionBuilder.add(cellName.column); } // for compact storage tables without clustering keys, the column holding the selected value is named // 'value' internally we add it to the selection here to prevent errors due to unexpected column names // when serializing the initial local data response if (metadata.isStaticCompactTable() && clusterings.isEmpty()) selectionBuilder.addAll(metadata.partitionColumns()); in.readBoolean(); // countCql3Rows // clusterings cannot include STATIC_CLUSTERING, so if the names filter is for static columns, clusterings // will be empty. However, by requesting the static columns in our ColumnFilter, this will still work. ClusteringIndexNamesFilter filter = new ClusteringIndexNamesFilter(clusterings, false); return Pair.create(selectionBuilder.build(), filter); } private long serializedNamesCommandSize(SinglePartitionReadCommand command) { ClusteringIndexNamesFilter filter = (ClusteringIndexNamesFilter)command.clusteringIndexFilter(); PartitionColumns columns = command.columnFilter().fetchedColumns(); return serializedNamesFilterSize(filter, command.metadata(), columns); } private void serializeSliceCommand(SinglePartitionReadCommand command, DataOutputPlus out) throws IOException { CFMetaData metadata = command.metadata(); ClusteringIndexSliceFilter filter = (ClusteringIndexSliceFilter)command.clusteringIndexFilter(); Slices slices = filter.requestedSlices(); boolean makeStaticSlice = !command.columnFilter().fetchedColumns().statics.isEmpty() && !slices.selects(Clustering.STATIC_CLUSTERING); serializeSlices(out, slices, filter.isReversed(), makeStaticSlice, metadata); out.writeBoolean(filter.isReversed()); boolean selectsStatics = !command.columnFilter().fetchedColumns().statics.isEmpty() || slices.selects(Clustering.STATIC_CLUSTERING); DataLimits limits = command.limits(); if (limits.isDistinct()) out.writeInt(1); // the limit is always 1 for DISTINCT queries else out.writeInt(updateLimitForQuery(command.limits().count(), filter.requestedSlices())); int compositesToGroup; if (limits.kind() == DataLimits.Kind.THRIFT_LIMIT || metadata.isDense()) compositesToGroup = -1; else if (limits.isDistinct() && !selectsStatics) compositesToGroup = -2; // for DISTINCT queries (CASSANDRA-8490) else compositesToGroup = metadata.clusteringColumns().size(); out.writeInt(compositesToGroup); } private SinglePartitionReadCommand deserializeSliceCommand(DataInputPlus in, boolean isDigest, CFMetaData metadata, DecoratedKey key, int nowInSeconds, int version) throws IOException { Pair p = deserializeSlicePartitionFilter(in, metadata); ClusteringIndexSliceFilter filter = p.left; boolean selectsStatics = p.right; int count = in.readInt(); int compositesToGroup = in.readInt(); // if a slice query from a pre-3.0 node doesn't cover statics, we shouldn't select them at all ColumnFilter columnFilter = LegacyRangeSliceCommandSerializer.getColumnSelectionForSlice(selectsStatics, compositesToGroup, metadata); // We have 2 types of DISTINCT queries: ones on only the partition key, and ones on the partition key and static columns. For the former, // we can easily detect the case because compositeToGroup is -2 and that's the only case it can be that. The latter is probablematic // however as we have no way to distinguish it from a normal select with a limit of 1 (and this, contrarily to the range query case // were the countCQL3Rows boolean allows us to decide). // So we consider this case not distinct here. This is ok because even if it is a distinct (with static), the count will be 1 and // we'll still just query one row (a distinct DataLimits currently behave exactly like a CQL limit with a count of 1). The only // drawback is that we'll send back the first row entirely while a 2.1/2.2 node would return only the first cell in that same // situation. This isn't a problem for 2.1/2.2 code however (it would be for a range query, as it would throw off the count for // reasons similar to CASSANDRA-10762, but it's ok for single partition queries). // We do _not_ want to do the reverse however and consider a 'SELECT * FROM foo LIMIT 1' as a DISTINCT query as that would make // us only return the 1st cell rather then 1st row. DataLimits limits; if (compositesToGroup == -2) limits = DataLimits.distinctLimits(count); // See CASSANDRA-8490 for the explanation of this value else if (compositesToGroup == -1) limits = DataLimits.thriftLimits(1, count); else limits = DataLimits.cqlLimits(count); // messages from old nodes will expect the thrift format, so always use 'true' for isForThrift return new SinglePartitionReadCommand(isDigest, version, true, metadata, nowInSeconds, columnFilter, RowFilter.NONE, limits, key, filter); } private long serializedSliceCommandSize(SinglePartitionReadCommand command) { CFMetaData metadata = command.metadata(); ClusteringIndexSliceFilter filter = (ClusteringIndexSliceFilter)command.clusteringIndexFilter(); Slices slices = filter.requestedSlices(); boolean makeStaticSlice = !command.columnFilter().fetchedColumns().statics.isEmpty() && !slices.selects(Clustering.STATIC_CLUSTERING); long size = serializedSlicesSize(slices, makeStaticSlice, metadata); size += TypeSizes.sizeof(command.clusteringIndexFilter().isReversed()); size += TypeSizes.sizeof(command.limits().count()); return size + TypeSizes.sizeof(0); // compositesToGroup } static void serializeSlices(DataOutputPlus out, Slices slices, boolean isReversed, boolean makeStaticSlice, CFMetaData metadata) throws IOException { out.writeInt(slices.size() + (makeStaticSlice ? 1 : 0)); // In 3.0 we always store the slices in normal comparator order. Pre-3.0 nodes expect the slices to // be in reversed order if the query is reversed, so we handle that here. if (isReversed) { for (int i = slices.size() - 1; i >= 0; i--) serializeSlice(out, slices.get(i), true, metadata); if (makeStaticSlice) serializeStaticSlice(out, true, metadata); } else { if (makeStaticSlice) serializeStaticSlice(out, false, metadata); for (Slice slice : slices) serializeSlice(out, slice, false, metadata); } } static long serializedSlicesSize(Slices slices, boolean makeStaticSlice, CFMetaData metadata) { long size = TypeSizes.sizeof(slices.size()); for (Slice slice : slices) { ByteBuffer sliceStart = LegacyLayout.encodeBound(metadata, slice.start(), true); size += ByteBufferUtil.serializedSizeWithShortLength(sliceStart); ByteBuffer sliceEnd = LegacyLayout.encodeBound(metadata, slice.end(), false); size += ByteBufferUtil.serializedSizeWithShortLength(sliceEnd); } if (makeStaticSlice) size += serializedStaticSliceSize(metadata); return size; } static long serializedStaticSliceSize(CFMetaData metadata) { // unlike serializeStaticSlice(), but we don't care about reversal for size calculations ByteBuffer sliceStart = LegacyLayout.encodeBound(metadata, ClusteringBound.BOTTOM, false); long size = ByteBufferUtil.serializedSizeWithShortLength(sliceStart); size += TypeSizes.sizeof((short) (metadata.comparator.size() * 3 + 2)); size += TypeSizes.sizeof((short) LegacyLayout.STATIC_PREFIX); for (int i = 0; i < metadata.comparator.size(); i++) { size += ByteBufferUtil.serializedSizeWithShortLength(ByteBufferUtil.EMPTY_BYTE_BUFFER); size += 1; // EOC } return size; } private static void serializeSlice(DataOutputPlus out, Slice slice, boolean isReversed, CFMetaData metadata) throws IOException { ByteBuffer sliceStart = LegacyLayout.encodeBound(metadata, isReversed ? slice.end() : slice.start(), !isReversed); ByteBufferUtil.writeWithShortLength(sliceStart, out); ByteBuffer sliceEnd = LegacyLayout.encodeBound(metadata, isReversed ? slice.start() : slice.end(), isReversed); ByteBufferUtil.writeWithShortLength(sliceEnd, out); } private static void serializeStaticSlice(DataOutputPlus out, boolean isReversed, CFMetaData metadata) throws IOException { // if reversed, write an empty bound for the slice start; if reversed, write out an empty bound for the // slice finish after we've written the static slice start if (!isReversed) { ByteBuffer sliceStart = LegacyLayout.encodeBound(metadata, ClusteringBound.BOTTOM, false); ByteBufferUtil.writeWithShortLength(sliceStart, out); } // write out the length of the composite out.writeShort(2 + metadata.comparator.size() * 3); // two bytes + EOC for each component, plus static prefix out.writeShort(LegacyLayout.STATIC_PREFIX); for (int i = 0; i < metadata.comparator.size(); i++) { ByteBufferUtil.writeWithShortLength(ByteBufferUtil.EMPTY_BYTE_BUFFER, out); // write the EOC, using an inclusive end if we're on the final component out.writeByte(i == metadata.comparator.size() - 1 ? 1 : 0); } if (isReversed) { ByteBuffer sliceStart = LegacyLayout.encodeBound(metadata, ClusteringBound.BOTTOM, false); ByteBufferUtil.writeWithShortLength(sliceStart, out); } } // Returns the deserialized filter, and whether static columns are queried (in pre-3.0, both info are determined by the slices, // but in 3.0 they are separated: whether static columns are queried or not depends on the ColumnFilter). static Pair deserializeSlicePartitionFilter(DataInputPlus in, CFMetaData metadata) throws IOException { int numSlices = in.readInt(); ByteBuffer[] startBuffers = new ByteBuffer[numSlices]; ByteBuffer[] finishBuffers = new ByteBuffer[numSlices]; for (int i = 0; i < numSlices; i++) { startBuffers[i] = ByteBufferUtil.readWithShortLength(in); finishBuffers[i] = ByteBufferUtil.readWithShortLength(in); } boolean reversed = in.readBoolean(); if (reversed) { // pre-3.0, reversed query slices put the greater element at the start of the slice ByteBuffer[] tmp = finishBuffers; finishBuffers = startBuffers; startBuffers = tmp; } boolean selectsStatics = false; Slices.Builder slicesBuilder = new Slices.Builder(metadata.comparator); for (int i = 0; i < numSlices; i++) { LegacyLayout.LegacyBound start = LegacyLayout.decodeBound(metadata, startBuffers[i], true); LegacyLayout.LegacyBound finish = LegacyLayout.decodeBound(metadata, finishBuffers[i], false); if (start.isStatic) { // If we start at the static block, this means we start at the beginning of the partition in 3.0 // terms (since 3.0 handles static outside of the slice). start = LegacyLayout.LegacyBound.BOTTOM; // Then if we include the static, records it if (start.bound.isInclusive()) selectsStatics = true; } else if (start == LegacyLayout.LegacyBound.BOTTOM) { selectsStatics = true; } // If the end of the slice is the end of the statics, then that mean this slice was just selecting static // columns. We have already recorded that in selectsStatics, so we can ignore the slice (which doesn't make // sense for 3.0). if (finish.isStatic) { assert finish.bound.isInclusive(); // it would make no sense for a pre-3.0 node to have a slice that stops // before the static columns (since there is nothing before that) continue; } slicesBuilder.add(Slice.make(start.bound, finish.bound)); } return Pair.create(new ClusteringIndexSliceFilter(slicesBuilder.build(), reversed), selectsStatics); } private static SinglePartitionReadCommand maybeConvertNamesToSlice(SinglePartitionReadCommand command) { if (command.clusteringIndexFilter().kind() != ClusteringIndexFilter.Kind.NAMES) return command; CFMetaData metadata = command.metadata(); if (!shouldConvertNamesToSlice(metadata, command.columnFilter().fetchedColumns())) return command; ClusteringIndexNamesFilter filter = (ClusteringIndexNamesFilter)command.clusteringIndexFilter(); ClusteringIndexSliceFilter sliceFilter = convertNamesFilterToSliceFilter(filter, metadata); return new SinglePartitionReadCommand( command.isDigestQuery(), command.digestVersion(), command.isForThrift(), metadata, command.nowInSec(), command.columnFilter(), command.rowFilter(), command.limits(), command.partitionKey(), sliceFilter); } /** * Returns true if a names filter on the given table and column selection should be converted to a slice * filter for compatibility with pre-3.0 nodes, false otherwise. */ static boolean shouldConvertNamesToSlice(CFMetaData metadata, PartitionColumns columns) { // On pre-3.0 nodes, due to CASSANDRA-5762, we always do a slice for CQL3 tables (not dense, composite). if (!metadata.isDense() && metadata.isCompound()) return true; // pre-3.0 nodes don't support names filters for reading collections, so if we're requesting any of those, // we need to convert this to a slice filter for (ColumnDefinition column : columns) { if (column.type.isMultiCell()) return true; } return false; } /** * Converts a names filter that is incompatible with pre-3.0 nodes to a slice filter that is compatible. */ private static ClusteringIndexSliceFilter convertNamesFilterToSliceFilter(ClusteringIndexNamesFilter filter, CFMetaData metadata) { SortedSet requestedRows = filter.requestedRows(); Slices slices; if (requestedRows.isEmpty()) { slices = Slices.NONE; } else if (requestedRows.size() == 1 && requestedRows.first().size() == 0) { slices = Slices.ALL; } else { Slices.Builder slicesBuilder = new Slices.Builder(metadata.comparator); for (Clustering clustering : requestedRows) slicesBuilder.add(ClusteringBound.inclusiveStartOf(clustering), ClusteringBound.inclusiveEndOf(clustering)); slices = slicesBuilder.build(); } return new ClusteringIndexSliceFilter(slices, filter.isReversed()); } /** * Potentially increases the existing query limit to account for the lack of exclusive bounds in pre-3.0 nodes. * @param limit the existing query limit * @param slices the requested slices * @return the updated limit */ static int updateLimitForQuery(int limit, Slices slices) { // Pre-3.0 nodes don't support exclusive bounds for slices. Instead, we query one more element if necessary // and filter it later (in LegacyRemoteDataResponse) if (!slices.hasLowerBound() && ! slices.hasUpperBound()) return limit; for (Slice slice : slices) { if (limit == Integer.MAX_VALUE) return limit; if (!slice.start().isInclusive()) limit++; if (!slice.end().isInclusive()) limit++; } return limit; } } }





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