1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
/*
* 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.spark.shuffle
import java.io._
import java.nio.ByteBuffer
import org.apache.spark.SparkEnv
import org.apache.spark.storage._
/**
* Create and maintain the shuffle blocks' mapping between logic block and physical file location.
* Data of shuffle blocks from the same map task are stored in a single consolidated data file.
* The offsets of the data blocks in the data file are stored in a separate index file.
*
* We use the name of the shuffle data's shuffleBlockId with reduce ID set to 0 and add ".data"
* as the filename postfix for data file, and ".index" as the filename postfix for index file.
*
*/
private[spark]
class IndexShuffleBlockManager extends ShuffleBlockManager {
private lazy val blockManager = SparkEnv.get.blockManager
/**
* Mapping to a single shuffleBlockId with reduce ID 0.
* */
def consolidateId(shuffleId: Int, mapId: Int): ShuffleBlockId = {
ShuffleBlockId(shuffleId, mapId, 0)
}
def getDataFile(shuffleId: Int, mapId: Int): File = {
blockManager.diskBlockManager.getFile(ShuffleDataBlockId(shuffleId, mapId, 0))
}
private def getIndexFile(shuffleId: Int, mapId: Int): File = {
blockManager.diskBlockManager.getFile(ShuffleIndexBlockId(shuffleId, mapId, 0))
}
/**
* Remove data file and index file that contain the output data from one map.
* */
def removeDataByMap(shuffleId: Int, mapId: Int): Unit = {
var file = getDataFile(shuffleId, mapId)
if (file.exists()) {
file.delete()
}
file = getIndexFile(shuffleId, mapId)
if (file.exists()) {
file.delete()
}
}
/**
* Write an index file with the offsets of each block, plus a final offset at the end for the
* end of the output file. This will be used by getBlockLocation to figure out where each block
* begins and ends.
* */
def writeIndexFile(shuffleId: Int, mapId: Int, lengths: Array[Long]) = {
val indexFile = getIndexFile(shuffleId, mapId)
val out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(indexFile)))
try {
// We take in lengths of each block, need to convert it to offsets.
var offset = 0L
out.writeLong(offset)
for (length <- lengths) {
offset += length
out.writeLong(offset)
}
} finally {
out.close()
}
}
/**
* Get the location of a block in a map output file. Uses the index file we create for it.
* */
private def getBlockLocation(blockId: ShuffleBlockId): FileSegment = {
// The block is actually going to be a range of a single map output file for this map, so
// find out the consolidated file, then the offset within that from our index
val indexFile = getIndexFile(blockId.shuffleId, blockId.mapId)
val in = new DataInputStream(new FileInputStream(indexFile))
try {
in.skip(blockId.reduceId * 8)
val offset = in.readLong()
val nextOffset = in.readLong()
new FileSegment(getDataFile(blockId.shuffleId, blockId.mapId), offset, nextOffset - offset)
} finally {
in.close()
}
}
override def getBytes(blockId: ShuffleBlockId): Option[ByteBuffer] = {
val segment = getBlockLocation(blockId)
blockManager.diskStore.getBytes(segment)
}
override def getBlockData(blockId: ShuffleBlockId): Either[FileSegment, ByteBuffer] = {
Left(getBlockLocation(blockId.asInstanceOf[ShuffleBlockId]))
}
override def stop() = {}
}
|
