time-skipping runtime foundation by feiyang3cat · Pull Request #9965 · temporalio/temporal

feiyang3cat · 2026-04-15T18:25:38Z

What changed?

taskGenerator:

add regenerate tasks for time skipping

mutableState:

new methods: add key methods to transition time
IsStateDirty: captures changes of time-skipping related fields
closeTransaction: add closeTransactionHandlerTimeSkipping

event: new time-skipping runtime event added
persistence: new runtime data added to execution info

Why?

add the foundational mechanism of how time skipping works in the runtime of a workflow execution

for reviewers:
this is a intergral foundation of t-s runtime, so it works without any granular and extended features as bound, replication, external-transfer tasks, etc. Over 50% of lines are tests/mocks/pb-gen. can focus on code first, then functional tests, and last ut.

How did you test it?

feiyang3cat · 2026-04-15T20:07:25Z

@@ -7110,6 +7232,8 @@ func (ms *MutableStateImpl) closeTransaction(
 		return closeTransactionResult{}, err
 	}



@yux0 it seems both active and passive cluster may both call closeTransaction, is it correct that if we want to add mutations of ms and generation of timer tasks in closeTransaction, we need to filter the policy for only active cluster

Correct, the passive will handle this by seeing the event in the history that the active added.

feiyang3cat · 2026-04-15T20:09:42Z

+
+		// time-skipping related methods
+		AddWorkflowExecutionTimeSkippingTransitionedEvent(ctx context.Context) (*historypb.HistoryEvent, error)
+		ApplyWorkflowExecutionTimeSkippingTransitionedEvent(ctx context.Context, event *historypb.HistoryEvent) error


@yux0 is it correct that we still need to add ApplyXXXEvent to support event-based replication?

why do we need to support event-based replication for this feature?

emm ~ Not sure if this is a question for me. Do we have standards to exclude features out of event-base replication or other replication method? I am assuming for completeness I need to support this so that replication center will catchup.

feiyang3cat · 2026-04-15T20:10:40Z

 	}
 	return true
 }
+


I haven't added this RegenerateTimerTasksForTimeSkipping in Refresh/PartialRefresh, and my understanding that the passive cluster will need it to generate timerTasks? @yux0

RegenerateTimerTasksForTimeSkipping would not be safe for use in partialRefresh as it adds new tasks rather than the idempotent adjustment that refreshTasksForTimer does. I think you would need to adjust refreshTaskForTimer by adding skipping to timer sequence.

oh I see. I think we may consider several options
(option-1) I can add a timeSkipped field in TimerInfo to obtain idempotentcy
(option-2) refreshTasksForTimer -> I need to judge if I need to regenerate beased on if WorkflowExecutionInfo.TimeSkippingInfo changed
(option-3) in semantics (not in performance speaking), this method is idempotent calling twice will generate another timerTask with the same content -> is this acceptable?

I will leave a todo here and arrange a meeting when I add the replication feature.

prathyushpv · 2026-04-15T20:24:34Z

+	targetTime time.Time,
+	triggeredDisable bool,
+) *historypb.HistoryEvent {
+	event := b.createHistoryEvent(enumspb.EVENT_TYPE_WORKFLOW_EXECUTION_TIME_SKIPPING_TRANSITIONED, b.timeSource.Now())


This b.timeSource.Now() can be called above and share in this line and 1092.

I guess you wanted to say the VirtualTime()? (this method will be deleted)

prathyushpv · 2026-04-15T20:25:19Z


 message TimeSkippingInfo {
-  // The config for the time skipping for the workflow.
+  // Current tconfiguration for the workflow.


nit: tconfiguration?

prathyushpv · 2026-04-15T20:26:22Z

+	skippedDuration := attr.GetTargetTime().AsTime().Sub(event.GetEventTime().AsTime())
+	disabledAfterBound := attr.GetDisabledAfterBound()
+
+	if ms.executionInfo.TimeSkippingInfo.AccumulatedSkippedDuration == nil {


Better to check if TimeSkippingInfo is nil before accessing the member.

added an error check

prathyushpv · 2026-04-15T20:30:22Z

+			nextUserTimerInfo = timerInfo
+		}
+	}
+	if !disabledAfterBound && nextUserTimerInfo == nil {


if disabledAfterBound is true and nextUserTimerInfo is nil, this check will not return an error. If that happens line 4027 below will panic.

I see that disabledAfterBound is always false now. But that could change when you fix the todo right?

prathyushpv · 2026-04-15T20:33:18Z

+
+func (ms *MutableStateImpl) GetTimeSkippingVirtualTime() time.Time {
+	// TODO@time-skipping: need to use this to adjust all timestamps for tasks sent to SDK worker.
+	offset := ms.GetExecutionInfo().TimeSkippingInfo.AccumulatedSkippedDuration


Nil check for TimeSkippingInfo?

method to be deleted.

prathyushpv · 2026-04-15T20:35:20Z

nit: This comment "this function must be the last call" could cause confusion later. Maybe clarify that this must be the last call before generating time skipping tasks.

simvlad · 2026-04-16T01:58:14Z

 		enumspb.EVENT_TYPE_WORKFLOW_EXECUTION_TIMED_OUT,
 		enumspb.EVENT_TYPE_WORKFLOW_EXECUTION_TERMINATED,
 		enumspb.EVENT_TYPE_WORKFLOW_EXECUTION_CONTINUED_AS_NEW,
+		enumspb.EVENT_TYPE_WORKFLOW_EXECUTION_TIME_SKIPPING_TRANSITIONED,


don't think it should be grouped under workflow state changes

simvlad · 2026-04-16T02:39:58Z

+}
+
+func (ms *MutableStateImpl) GetTimeSkippingVirtualTime() time.Time {
+	// TODO@time-skipping: need to use this to adjust all timestamps for tasks sent to SDK worker.


My understanding was that we will use a single TimeSource implementation and all events would use virtual timestamps, so no adjustment would be needed. Is that still the plan?

you are right. let me change back the design and try to figure out how to make that simple. I will need to put that in another pr as this pr is growing large.

yycptt · 2026-04-16T23:38:44Z

 	timerSequence := t.getTimerSequence(mutableState)
 	referenceTime := t.Now()
+	if tsInfo := mutableState.GetExecutionInfo().GetTimeSkippingInfo(); tsInfo != nil && tsInfo.GetAccumulatedSkippedDuration() != nil {
+		referenceTime = mutableState.GetTimeSkippingVirtualTime()


do we need this for other timer tasks?

I understand for example there's no running activity at time skipping time, but there could be after time is skipped and we need to use the workflow time?

this is bad design, removed

yycptt · 2026-04-16T23:43:42Z

+	// pendingTimerInfoIDs in mutable state is only timers that need regenerated
+	// and the new timerTasks should not change the original pendingTimerInfoIDs in mutable state
+	for _, timerInfo := range r.mutableState.GetPendingTimerInfos() {
+		visibilityTimestamp := timerInfo.ExpiryTime.AsTime().Add(-accumulatedSkippedDuration)


maybe I confused myself. I think we need to adjust timestamp for all timer tasks generated if time for a workflow is ever skipped?

yycptt · 2026-04-16T23:46:17Z

 	}
 }

+func (ms *MutableStateImpl) closeTransactionHandlerTimeSkipping(


Suggested change

func (ms *MutableStateImpl) closeTransactionHandlerTimeSkipping(

func (ms *MutableStateImpl) closeTransactionHandleTimeSkipping(

feiyang3cat requested review from a team as code owners April 15, 2026 18:25

feiyang3cat force-pushed the ts/runtime-1 branch 3 times, most recently from 4ae2cfe to c2a602f Compare April 15, 2026 19:03

feiyang3cat commented Apr 15, 2026

View reviewed changes

prathyushpv reviewed Apr 15, 2026

View reviewed changes

feiyang3cat force-pushed the ts/runtime-1 branch from 88762a2 to c2a602f Compare April 15, 2026 21:29

simvlad reviewed Apr 16, 2026

View reviewed changes

feiyang3cat added 10 commits April 16, 2026 11:03

add basic runtime support of time skipping

153595b

add task generation logic for time-skipping

2bcec36

IsDirty tracks changes brought by time-skipping

7099ad7

add ut for timeskipping task generation

85baae9

add ut for ms methods for timeskipping

2bdea0b

add timeskipping to executeUserTimerTimeoutTask time check

95a6def

fix golangci lint

2cac079

fix bugs

47ea63c

fix bugs in Add and Apply WorkflowExecutionTimeSkippingTransitionedEvent

ba5a8f8

made internal functions of ms private

0a9224f

feiyang3cat force-pushed the ts/runtime-1 branch from c2a602f to 0a9224f Compare April 16, 2026 22:46

yycptt reviewed Apr 16, 2026

View reviewed changes

rm GetVirtualTime and functional tests for another pr

79f7257

feiyang3cat force-pushed the ts/runtime-1 branch 2 times, most recently from 17add5c to 5e70e98 Compare April 17, 2026 01:09

add tests for closeTransaction and fix bugs

5a229af

feiyang3cat force-pushed the ts/runtime-1 branch from 5e70e98 to 5a229af Compare April 17, 2026 01:12

		@@ -7110,6 +7232,8 @@ func (ms *MutableStateImpl) closeTransaction(
		return closeTransactionResult{}, err
		}

	func (ms *MutableStateImpl) closeTransactionHandlerTimeSkipping(
	func (ms *MutableStateImpl) closeTransactionHandleTimeSkipping(

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feiyang3cat commented Apr 15, 2026 •

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