Temporal Troubleshooting

Guidance for diagnosing and resolving common Temporal workflow issues.

Diagnostic Approach

1. Identify symptoms - What's the observable problem?
2. Gather information - Check status, events, logs
3. Isolate cause - Narrow down to specific component
4. Apply fix - Resolve with targeted solution
5. Verify resolution - Confirm problem is fixed

Quick Diagnostics

Check Workflow Status

# Describe workflow
temporal workflow describe --workflow-id <id>

# List running workflows
temporal workflow list --query "ExecutionStatus='Running'"

# List failed workflows
temporal workflow list --query "ExecutionStatus='Failed'"

Check Event History

# Show all events
temporal workflow show --workflow-id <id>

# Get JSON for parsing
temporal workflow show --workflow-id <id> --output json > history.json

# Find specific events
temporal workflow show --workflow-id <id> --output json | \
  jq '.events[] | select(.eventType | contains("Failed"))'

Check Task Queue

# Describe task queue
temporal task-queue describe --task-queue <queue>

Common Issues

Issue: Workflow Stuck (Not Progressing)

Symptoms:

• Workflow status is "Running" but nothing happening
• No recent events in history

Diagnosis Tree:

Workflow stuck
├── Last event is ActivityTaskScheduled?
│   ├── Workers running? → Check/start workers
│   ├── Correct task queue? → Fix queue name
│   └── Activity timed out? → Check timeout config
├── Last event is TimerStarted?
│   └── Timer still pending → Wait or reset
├── Last event is SignalExternalWorkflow?
│   └── Target workflow not responding → Check target
└── Last event is WorkflowTaskScheduled?
    ├── Workers running? → Check/start workers
    └── Workflow error? → Check worker logs

Commands:

# Check what workflow is waiting for
temporal workflow show --workflow-id <id> | tail -20

# Check if workers are connected
temporal task-queue describe --task-queue <queue>

Solutions:

Waiting For	Solution
Activity	Start workers, fix task queue
Timer	Wait or reset workflow
Signal	Send signal or reset
Child workflow	Check child status
Nexus operation	Check endpoint and handler workers

Issue: Non-Determinism Error

Symptoms:

• Error: non-deterministic workflow definition
• Error: history mismatch
• Workflow fails on replay

Common Causes:

1. Time-based decisions

   // BAD
   if time.Now().Hour() < 12 { }
   
   // GOOD
   if workflow.Now(ctx).Hour() < 12 { }
   

2. Random values

   // BAD
   id := uuid.New()
   
   // GOOD
   var id string
   workflow.SideEffect(ctx, func(ctx workflow.Context) interface{} {
       return uuid.New().String()
   }).Get(&id)
   

3. Map iteration order

   // BAD - order varies
   for k, v := range myMap { }
   
   // GOOD - deterministic order
   keys := make([]string, 0, len(myMap))
   for k := range myMap {
       keys = append(keys, k)
   }
   sort.Strings(keys)
   for _, k := range keys {
       v := myMap[k]
   }
   

4. Code changes without versioning

   // When changing workflow logic, use GetVersion
   v := workflow.GetVersion(ctx, "change-id", workflow.DefaultVersion, 1)
   if v == workflow.DefaultVersion {
       // Old logic
   } else {
       // New logic
   }
   

Diagnosis:

# Export history
temporal workflow show --workflow-id <id> --output json > history.json

# Create replay test

func TestReplay(t *testing.T) {
    replayer := worker.NewWorkflowReplayer()
    replayer.RegisterWorkflow(YourWorkflow)
    err := replayer.ReplayWorkflowHistoryFromJSONFile(nil, "history.json")
    require.NoError(t, err)
}

Issue: Activity Timeout

Symptoms:

• Activity fails with timeout error
• ActivityTaskTimedOut events in history

Timeout Types:

Timeout	Meaning	Solution
ScheduleToStart	Waiting for worker	Add workers, check queue
StartToClose	Execution too long	Increase timeout or optimize
ScheduleToClose	Total time exceeded	Increase or split activity
Heartbeat	No heartbeat received	Add heartbeat, check worker

Diagnosis:

# Find timeout events
temporal workflow show --workflow-id <id> --output json | \
  jq '.events[] | select(.eventType == "ActivityTaskTimedOut")'

Solutions:

ao := workflow.ActivityOptions{
    // Increase timeouts if needed
    StartToCloseTimeout: 30 * time.Minute,

    // Add heartbeat for long activities
    HeartbeatTimeout: 30 * time.Second,

    // Configure retries
    RetryPolicy: &temporal.RetryPolicy{
        MaximumAttempts: 5,
    },
}

Issue: Activity Failures

Symptoms:

• Activities failing repeatedly
• ActivityTaskFailed events

Diagnosis:

# Find failure details
temporal workflow show --workflow-id <id> --output json | \
  jq '.events[] | select(.eventType == "ActivityTaskFailed") | .activityTaskFailedEventAttributes'

Common Causes:

Error Type	Cause	Solution
Connection error	Network issue	Add retries, check connectivity
Panic	Code bug	Fix activity code
Application error	Business logic	Check error handling
Resource exhausted	Rate limiting	Add backoff, reduce load

Issue: High Latency

Symptoms:

• Workflows slow to progress
• Long time between events

Check Points:

# Schedule-to-start latency (Prometheus)
histogram_quantile(0.99, rate(temporal_schedule_to_start_latency_bucket[5m]))

# Persistence latency
histogram_quantile(0.99, rate(temporal_persistence_latency_bucket[5m]))

Solutions:

Latency Location	Solution
Schedule-to-start	Add workers
Activity execution	Optimize activity
Database	Scale database
Network	Check connectivity

Issue: Nexus Operation Failures

Symptoms:

• NexusOperationFailed or NexusOperationTimedOut events in caller workflow history
• Caller workflow stuck waiting for Nexus operation

Diagnosis Tree:

Nexus operation issue
├── NexusOperationTimedOut?
│   ├── scheduleToCloseTimeout too short → Increase timeout
│   └── Handler workflow stuck → Debug handler workflow in handler namespace
├── NexusOperationFailed?
│   ├── OperationError → Check handler operation logic
│   ├── HandlerError → Check handler worker logs/infrastructure
│   └── Endpoint misconfigured → Verify endpoint config
└── NexusOperationScheduled but never started?
    ├── Endpoint exists? → temporal operator nexus endpoint list
    ├── Handler workers running? → Check handler task queue
    └── Target namespace accessible? → Verify namespace exists

Diagnostic Commands:

# Check Nexus events in caller workflow
temporal workflow show --workflow-id <caller-wf-id> --output json | \
  jq '.events[] | select(.eventType | contains("Nexus"))'

# List Nexus endpoints
temporal operator nexus endpoint list

# Describe specific endpoint
temporal operator nexus endpoint describe --name <endpoint-name>

# Check handler task queue in handler namespace
temporal task-queue describe --task-queue <handler-tq> --namespace <handler-ns>

Common Nexus Issues:

Issue	Cause	Solution
Endpoint not found	Endpoint not created or wrong name	Create/verify endpoint
Handler not responding	No workers on handler task queue	Start handler workers
Operation timeout	scheduleToCloseTimeout too short	Increase caller timeout
Handler error	Bug in handler operation code	Fix handler code
Cross-namespace auth	Permissions not configured	Configure namespace access

Recovery Actions

Reset Workflow

Reset to retry from a specific point:

# Reset to specific event
temporal workflow reset \
  --workflow-id <id> \
  --event-id <event-id> \
  --reason "Reset for retry"

# Reset to last workflow task
temporal workflow reset \
  --workflow-id <id> \
  --type LastWorkflowTask \
  --reason "Reset after fix"

Terminate Workflow

Force stop a stuck workflow:

temporal workflow terminate \
  --workflow-id <id> \
  --reason "Manual termination - issue description"

Cancel Workflow

Request graceful cancellation:

temporal workflow cancel --workflow-id <id>

Prevention

• Use replay tests in CI/CD
• Monitor key metrics
• Set appropriate timeouts
• Add heartbeats to long activities
• Use GetVersion for workflow changes
• Test with the production history

Additional Resources

Reference Files

For detailed error catalogs, consult:

• references/error-catalog.md - Complete error reference
• references/diagnostic-queries.md - Prometheus queries