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scheduleWithFixedDelay vs scheduleAtFixedRate, #26910

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* previous `schedule` method is trying to maintain a fixed average frequency
  over time, but that can result in undesired bursts of scheduled tasks after a long
  GC or if the JVM process has been suspended, same with all other periodic
  scheduled message sending via various Timer APIs
* most of the time "fixed delay" is more desirable
* we can't just change because it's too big behavioral change and some might
  depend on previous behavior
* deprecate the old `schedule` and introduce new `scheduleWithFixedDelay`
  and `scheduleAtFixedRate`, when fixing the deprecation warning users should
  make a concious decision of which behavior to use (scheduleWithFixedDelay in
  most cases)

* Streams
* SchedulerSpec
  * test both fixed delay and fixed rate
* TimerSpec
* FSM and PersistentFSM
* mima
* runnable as second parameter list, also in typed.Scheduler
* IllegalStateException vs SchedulerException
* deprecated annotations
* api and reference docs, all places
* migration guide
This commit is contained in:
Patrik Nordwall 2019-05-27 11:53:26 +02:00
parent 72cfc2485e
commit 10d32fceb9
99 changed files with 2285 additions and 909 deletions
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16
akka-cluster-tools/src/main/scala/akka/cluster/singleton/ClusterSingletonManager.scala
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@ -569,7 +569,7 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
// subscribe to cluster changes, re-subscribe when restart
cluster.subscribe(self, ClusterEvent.InitialStateAsEvents, classOf[MemberRemoved], classOf[MemberDowned])
setTimer(CleanupTimer, Cleanup, 1.minute, repeat = true)
startTimerWithFixedDelay(CleanupTimer, Cleanup, 1.minute)
// defer subscription to avoid some jitter when
// starting/joining several nodes at the same time
@ -723,7 +723,7 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
if (count <= maxHandOverRetries) {
logInfo("Retry [{}], sending HandOverToMe to [{}]", count, previousOldestOption.map(_.address))
previousOldestOption.foreach(node => peer(node.address) ! HandOverToMe)
setTimer(HandOverRetryTimer, HandOverRetry(count + 1), handOverRetryInterval, repeat = false)
startSingleTimer(HandOverRetryTimer, HandOverRetry(count + 1), handOverRetryInterval)
stay()
} else if (previousOldestOption.forall(removed.contains)) {
// can't send HandOverToMe, previousOldest unknown for new node (or restart)
@ -771,7 +771,7 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
if (result) {
gotoOldest()
} else {
setTimer(LeaseRetryTimer, LeaseRetry, leaseRetryInterval)
startSingleTimer(LeaseRetryTimer, LeaseRetry, leaseRetryInterval)
stay.using(AcquiringLeaseData(leaseRequestInProgress = false, None))
}
case Event(Terminated(ref), AcquiringLeaseData(_, Some(singleton))) if ref == singleton =>
@ -780,7 +780,7 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
tryAcquireLease()
case Event(AcquireLeaseFailure(t), _) =>
log.error(t, "failed to get lease (will be retried)")
setTimer(LeaseRetryTimer, LeaseRetry, leaseRetryInterval)
startSingleTimer(LeaseRetryTimer, LeaseRetry, leaseRetryInterval)
stay.using(AcquiringLeaseData(leaseRequestInProgress = false, None))
case Event(LeaseRetry, _) =>
// If lease was lost (so previous state was oldest) then we don't try and get the lease
@ -827,11 +827,11 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
case Some(a) =>
// send TakeOver request in case the new oldest doesn't know previous oldest
peer(a.address) ! TakeOverFromMe
setTimer(TakeOverRetryTimer, TakeOverRetry(1), handOverRetryInterval, repeat = false)
startSingleTimer(TakeOverRetryTimer, TakeOverRetry(1), handOverRetryInterval)
goto(WasOldest).using(WasOldestData(singleton, newOldestOption = Some(a)))
case None =>
// new oldest will initiate the hand-over
setTimer(TakeOverRetryTimer, TakeOverRetry(1), handOverRetryInterval, repeat = false)
startSingleTimer(TakeOverRetryTimer, TakeOverRetry(1), handOverRetryInterval)
goto(WasOldest).using(WasOldestData(singleton, newOldestOption = None))
}
}
@ -890,7 +890,7 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
else
log.debug("Retry [{}], sending TakeOverFromMe to [{}]", count, newOldestOption.map(_.address))
newOldestOption.foreach(node => peer(node.address) ! TakeOverFromMe)
setTimer(TakeOverRetryTimer, TakeOverRetry(count + 1), handOverRetryInterval, repeat = false)
startSingleTimer(TakeOverRetryTimer, TakeOverRetry(count + 1), handOverRetryInterval)
stay
} else
throw new ClusterSingletonManagerIsStuck(s"Expected hand-over to [$newOldestOption] never occurred")
@ -1043,7 +1043,7 @@ class ClusterSingletonManager(singletonProps: Props, terminationMessage: Any, se
}
onTransition {
case _ -> BecomingOldest => setTimer(HandOverRetryTimer, HandOverRetry(1), handOverRetryInterval, repeat = false)
case _ -> BecomingOldest => startSingleTimer(HandOverRetryTimer, HandOverRetry(1), handOverRetryInterval)
}
onTransition {