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
|
package spark.scheduler
import java.net.URI
import spark._
import spark.storage.BlockManagerId
/**
* A stage is a set of independent tasks all computing the same function that need to run as part
* of a Spark job, where all the tasks have the same shuffle dependencies. Each DAG of tasks run
* by the scheduler is split up into stages at the boundaries where shuffle occurs, and then the
* DAGScheduler runs these stages in topological order.
*
* Each Stage can either be a shuffle map stage, in which case its tasks' results are input for
* another stage, or a result stage, in which case its tasks directly compute the action that
* initiated a job (e.g. count(), save(), etc). For shuffle map stages, we also track the nodes
* that each output partition is on.
*
* Each Stage also has a priority, which is (by default) based on the job it was submitted in.
* This allows Stages from earlier jobs to be computed first or recovered faster on failure.
*/
private[spark] class Stage(
val id: Int,
val rdd: RDD[_],
val shuffleDep: Option[ShuffleDependency[_,_]], // Output shuffle if stage is a map stage
val parents: List[Stage],
val priority: Int)
extends Logging {
val isShuffleMap = shuffleDep != None
val numPartitions = rdd.splits.size
val outputLocs = Array.fill[List[MapStatus]](numPartitions)(Nil)
var numAvailableOutputs = 0
private var nextAttemptId = 0
def isAvailable: Boolean = {
if (!isShuffleMap) {
true
} else {
numAvailableOutputs == numPartitions
}
}
def addOutputLoc(partition: Int, status: MapStatus) {
val prevList = outputLocs(partition)
outputLocs(partition) = status :: prevList
if (prevList == Nil)
numAvailableOutputs += 1
}
def removeOutputLoc(partition: Int, bmAddress: BlockManagerId) {
val prevList = outputLocs(partition)
val newList = prevList.filterNot(_.address == bmAddress)
outputLocs(partition) = newList
if (prevList != Nil && newList == Nil) {
numAvailableOutputs -= 1
}
}
def removeOutputsOnHost(host: String) {
var becameUnavailable = false
for (partition <- 0 until numPartitions) {
val prevList = outputLocs(partition)
val newList = prevList.filterNot(_.address.ip == host)
outputLocs(partition) = newList
if (prevList != Nil && newList == Nil) {
becameUnavailable = true
numAvailableOutputs -= 1
}
}
if (becameUnavailable) {
logInfo("%s is now unavailable on %s (%d/%d, %s)".format(this, host, numAvailableOutputs, numPartitions, isAvailable))
}
}
def newAttemptId(): Int = {
val id = nextAttemptId
nextAttemptId += 1
return id
}
def origin: String = rdd.origin
override def toString = "Stage " + id // + ": [RDD = " + rdd.id + ", isShuffle = " + isShuffleMap + "]"
override def hashCode(): Int = id
}
|