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https://issues.apache.org/jira/browse/GEARPUMP-32?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15429976#comment-15429976
]
ASF GitHub Bot commented on GEARPUMP-32:
----------------------------------------
Github user huafengw commented on a diff in the pull request:
https://github.com/apache/incubator-gearpump/pull/67#discussion_r75612603
--- Diff:
streaming/src/main/scala/org/apache/gearpump/streaming/task/TaskActor.scala ---
@@ -322,11 +305,45 @@ class TaskActor(
private def getSubscription(processorId: ProcessorId):
Option[Subscription] = {
subscriptions.find(_._1 == processorId).map(_._2)
}
+
+ private def updateUpstreamMinClock(upstreamClock: TimeStamp): Unit = {
+ if (upstreamClock > this.upstreamMinClock) {
+ task.onWatermarkProgress(Instant.ofEpochMilli(this.upstreamMinClock))
+ }
+ this.upstreamMinClock = upstreamClock
+
+ val subMinClock = subscriptions.foldLeft(Long.MaxValue) { (min, sub) =>
+ val subMin = sub._2.minClock
+ // A subscription is holding back the _minClock;
+ // we send AckRequest to its tasks to push _minClock forward
+ if (subMin == _minClock) {
+ sub._2.sendAckRequestOnStallingTime(_minClock)
+ }
+ Math.min(min, subMin)
+ }
+
+ _minClock = Math.max(life.birth, Math.min(upstreamMinClock,
subMinClock))
+
+ val update = UpdateClock(taskId, _minClock)
+ context.system.scheduler.scheduleOnce(CLOCK_REPORT_INTERVAL) {
+ LOG.info(s"send update $update")
--- End diff --
Change to debug?
> Minimum clock of source Tasks maybe inaccurate
> ----------------------------------------------
>
> Key: GEARPUMP-32
> URL: https://issues.apache.org/jira/browse/GEARPUMP-32
> Project: Apache Gearpump
> Issue Type: Bug
> Components: streaming
> Affects Versions: 0.8.0
> Reporter: Manu Zhang
> Assignee: Manu Zhang
> Fix For: 0.8.1
>
>
> Moved from [https://github.com/gearpump/gearpump/issues/1835] and reported by
> [Zhu Yueqian|https://github.com/yueqianzhu]
> {quote}
> Source tasks have not any upstreamClocks. So, startClock is the minimum of
> pending clocks when recover happen.
> eg below:
> source task1: timeStamp:15,not ACK, minClockValue maybe is 15(<= 15).
> source task2: timeStamp:10,ACKed, minClockValue maybe is Long.MaxValue
> when recover happen,startClock maybe is 15. where is the data between 10 to
> 15 at task2?
> {quote}
> More context on this issue:
> In Gearpump, we maintain a global minimum clock tracked from a message's
> timestamp across all tasks. It means messages with timestamp before this
> clock have all been processed. An application will restart from this value on
> failure, and thus at-least-once message delivery could be guaranteed.
> The global minimum clock is the lower bound of all the Tasks' minimum clocks.
> For a task, the minimum clock is the lower of
> # upstream minimum clock
> # a. the minimum timestamp of unacked messages
> b. Long.MaxValue if all messages have been acked.
>
> Note that 2.b allows the global minimum clock to progress and it is almost
> safe since the clock is also bounded by the upstream minimum clock. I said
> "almost safe" because a source task has no upstream but we assume the
> upstream minimum clock is Long.MaxValue. Thus, the scenario described by Zhu
> Yueqian could happen and breaks at-least-once guarantee.
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