| /* |
| * 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.io.sstable; |
| |
| import java.io.*; |
| import java.util.Collections; |
| import java.util.List; |
| |
| import org.apache.cassandra.config.CFMetaData; |
| import org.apache.cassandra.db.*; |
| import org.apache.cassandra.io.ISerializer; |
| import org.apache.cassandra.io.sstable.format.Version; |
| import org.apache.cassandra.io.util.DataInputPlus; |
| import org.apache.cassandra.io.util.DataOutputPlus; |
| import org.apache.cassandra.utils.*; |
| |
| /** |
| * Provides helper to serialize, deserialize and use column indexes. |
| */ |
| public final class IndexHelper |
| { |
| private IndexHelper() |
| { |
| } |
| |
| /** |
| * The index of the IndexInfo in which a scan starting with @name should begin. |
| * |
| * @param name name to search for |
| * @param indexList list of the indexInfo objects |
| * @param comparator the comparator to use |
| * @param reversed whether or not the search is reversed, i.e. we scan forward or backward from name |
| * @param lastIndex where to start the search from in indexList |
| * |
| * @return int index |
| */ |
| public static int indexFor(ClusteringPrefix name, List<IndexInfo> indexList, ClusteringComparator comparator, boolean reversed, int lastIndex) |
| { |
| IndexInfo target = new IndexInfo(name, name, 0, 0, null); |
| /* |
| Take the example from the unit test, and say your index looks like this: |
| [0..5][10..15][20..25] |
| and you look for the slice [13..17]. |
| |
| When doing forward slice, we are doing a binary search comparing 13 (the start of the query) |
| to the lastName part of the index slot. You'll end up with the "first" slot, going from left to right, |
| that may contain the start. |
| |
| When doing a reverse slice, we do the same thing, only using as a start column the end of the query, |
| i.e. 17 in this example, compared to the firstName part of the index slots. bsearch will give us the |
| first slot where firstName > start ([20..25] here), so we subtract an extra one to get the slot just before. |
| */ |
| int startIdx = 0; |
| List<IndexInfo> toSearch = indexList; |
| if (reversed) |
| { |
| if (lastIndex < indexList.size() - 1) |
| { |
| toSearch = indexList.subList(0, lastIndex + 1); |
| } |
| } |
| else |
| { |
| if (lastIndex > 0) |
| { |
| startIdx = lastIndex; |
| toSearch = indexList.subList(lastIndex, indexList.size()); |
| } |
| } |
| int index = Collections.binarySearch(toSearch, target, comparator.indexComparator(reversed)); |
| return startIdx + (index < 0 ? -index - (reversed ? 2 : 1) : index); |
| } |
| |
| public static class IndexInfo |
| { |
| private static final long EMPTY_SIZE = ObjectSizes.measure(new IndexInfo(null, null, 0, 0, null)); |
| |
| public final long offset; |
| public final long width; |
| public final ClusteringPrefix firstName; |
| public final ClusteringPrefix lastName; |
| |
| // If at the end of the index block there is an open range tombstone marker, this marker |
| // deletion infos. null otherwise. |
| public final DeletionTime endOpenMarker; |
| |
| public IndexInfo(ClusteringPrefix firstName, |
| ClusteringPrefix lastName, |
| long offset, |
| long width, |
| DeletionTime endOpenMarker) |
| { |
| this.firstName = firstName; |
| this.lastName = lastName; |
| this.offset = offset; |
| this.width = width; |
| this.endOpenMarker = endOpenMarker; |
| } |
| |
| public static class Serializer |
| { |
| // This is the default index size that we use to delta-encode width when serializing so we get better vint-encoding. |
| // This is imperfect as user can change the index size and ideally we would save the index size used with each index file |
| // to use as base. However, that's a bit more involved a change that we want for now and very seldom do use change the index |
| // size so using the default is almost surely better than using no base at all. |
| public static final long WIDTH_BASE = 64 * 1024; |
| |
| private final ISerializer<ClusteringPrefix> clusteringSerializer; |
| private final Version version; |
| |
| public Serializer(CFMetaData metadata, Version version, SerializationHeader header) |
| { |
| this.clusteringSerializer = metadata.serializers().indexEntryClusteringPrefixSerializer(version, header); |
| this.version = version; |
| } |
| |
| public void serialize(IndexInfo info, DataOutputPlus out) throws IOException |
| { |
| assert version.storeRows() : "We read old index files but we should never write them"; |
| |
| clusteringSerializer.serialize(info.firstName, out); |
| clusteringSerializer.serialize(info.lastName, out); |
| out.writeUnsignedVInt(info.offset); |
| out.writeVInt(info.width - WIDTH_BASE); |
| |
| out.writeBoolean(info.endOpenMarker != null); |
| if (info.endOpenMarker != null) |
| DeletionTime.serializer.serialize(info.endOpenMarker, out); |
| } |
| |
| public IndexInfo deserialize(DataInputPlus in) throws IOException |
| { |
| ClusteringPrefix firstName = clusteringSerializer.deserialize(in); |
| ClusteringPrefix lastName = clusteringSerializer.deserialize(in); |
| long offset; |
| long width; |
| DeletionTime endOpenMarker = null; |
| if (version.storeRows()) |
| { |
| offset = in.readUnsignedVInt(); |
| width = in.readVInt() + WIDTH_BASE; |
| if (in.readBoolean()) |
| endOpenMarker = DeletionTime.serializer.deserialize(in); |
| } |
| else |
| { |
| offset = in.readLong(); |
| width = in.readLong(); |
| } |
| return new IndexInfo(firstName, lastName, offset, width, endOpenMarker); |
| } |
| |
| public long serializedSize(IndexInfo info) |
| { |
| assert version.storeRows() : "We read old index files but we should never write them"; |
| |
| long size = clusteringSerializer.serializedSize(info.firstName) |
| + clusteringSerializer.serializedSize(info.lastName) |
| + TypeSizes.sizeofUnsignedVInt(info.offset) |
| + TypeSizes.sizeofVInt(info.width - WIDTH_BASE) |
| + TypeSizes.sizeof(info.endOpenMarker != null); |
| |
| if (info.endOpenMarker != null) |
| size += DeletionTime.serializer.serializedSize(info.endOpenMarker); |
| return size; |
| } |
| } |
| |
| public long unsharedHeapSize() |
| { |
| return EMPTY_SIZE |
| + firstName.unsharedHeapSize() |
| + lastName.unsharedHeapSize() |
| + (endOpenMarker == null ? 0 : endOpenMarker.unsharedHeapSize()); |
| } |
| } |
| } |