Timeline Analysis

What is Timeline Analysis?

Timeline Analysis reconstructs the sequence of events:

1. Identify start of incident
2. Map all events in chronological order
3. Correlate events across systems
4. Identify trigger and contributing factors
5. Understand cascading effects

Benefits:
├── Clear picture of what happened
├── Identify trigger point
├── Understand cascading effects
├── Find correlation between events
└── Prevent future incidents

Timeline Components

Timeline Elements:
├── Time (timestamp)
├── Event (what happened)
├── Source (where it happened)
├── Impact (what was affected)
├── Action (what was done)
└── Result (what was the outcome)

Example Timeline

14:00:00 - Deployment started
14:05:00 - Code deployed to production
14:10:00 - Cache cleared
14:15:00 - Errors start appearing
14:20:00 - Monitoring alerts triggered
14:25:00 - Team notified
14:30:00 - Investigation started
14:35:00 - Root cause identified
14:40:00 - Rollback initiated
14:45:00 - Rollback completed
14:50:00 - System verified
14:55:00 - Incident resolved

Gather Timeline Data

// Collect events from multiple sources
class TimelineCollector
{
    public function collectEvents($startTime, $endTime)
    {
        $events = [];
        
        // Application logs
        $events = array_merge($events, $this->getAppLogs($startTime, $endTime));
        
        // Database logs
        $events = array_merge($events, $this->getDbLogs($startTime, $endTime));
        
        // Server logs
        $events = array_merge($events, $this->getServerLogs($startTime, $endTime));
        
        // Monitoring alerts
        $events = array_merge($events, $this->getAlerts($startTime, $endTime));
        
        // Deployment records
        $events = array_merge($events, $this->getDeployments($startTime, $endTime));
        
        // Sort by timestamp
        usort($events, function($a, $b) {
            return $a['timestamp'] - $b['timestamp'];
        });
        
        return $events;
    }
}

Map Event Sequence

// Create event sequence
class EventSequencer
{
    public function sequence($events)
    {
        $sequence = [];
        $previousEvent = null;
        
        foreach ($events as $event) {
            $sequenceEvent = [
                'timestamp' => $event['timestamp'],
                'event' => $event['description'],
                'source' => $event['source'],
                'impact' => $this->determineImpact($event),
                'causality' => $previousEvent ? $this->determineCausality($previousEvent, $event) : null
            ];
            
            $sequence[] = $sequenceEvent;
            $previousEvent = $event;
        }
        
        return $sequence;
    }
    
    private function determineCausality($prev, $current)
    {
        // Determine if events are causally related
        if ($prev['source'] === $current['source']) {
            return 'same_source';
        }
        
        if (abs($prev['timestamp'] - $current['timestamp']) < 60) {
            return 'temporal';
        }
        
        return 'unrelated';
    }
}

Correlate Events Across Systems

// Correlation engine
class EventCorrelator
{
    public function correlate($events)
    {
        $correlated = [];
        
        foreach ($events as $event) {
            $key = $this->generateCorrelationKey($event);
            
            if (!isset($correlated[$key])) {
                $correlated[$key] = [];
            }
            
            $correlated[$key][] = $event;
        }
        
        return $correlated;
    }
    
    private function generateCorrelationKey($event)
    {
        // Use request ID, user ID, or order ID
        if (isset($event['request_id'])) {
            return 'request_' . $event['request_id'];
        }
        
        if (isset($event['order_id'])) {
            return 'order_' . $event['order_id'];
        }
        
        if (isset($event['user_id'])) {
            return 'user_' . $event['user_id'];
        }
        
        return 'time_' . floor($event['timestamp'] / 60);
    }
}

Correlation Examples

Correlation by Request ID:
├── 14:15:00 - Request ABC123 received
├── 14:15:01 - Request ABC123 - MySQL query
├── 14:15:02 - Request ABC123 - Redis cache miss
├── 14:15:03 - Request ABC123 - Payment gateway call
└── 14:15:04 - Request ABC123 - Response sent

Correlation by Order ID:
├── 14:20:00 - Order 456 created
├── 14:20:01 - Order 456 - Payment processed
├── 14:20:02 - Order 456 - Inventory reserved
├── 14:20:03 - Order 456 - Email sent
└── 14:20:04 - Order 456 - Status updated

Correlation by Time Window:
├── 14:15:00-14:16:00 - Multiple errors
├── 14:15:00 - MySQL connection error
├── 14:15:01 - Redis timeout
├── 14:15:02 - Payment gateway error
└── 14:15:03 - Application crash

Identify Patterns

// Pattern detection
class PatternDetector
{
    public function detect($events)
    {
        $patterns = [];
        
        // Detect error spikes
        $errorSpike = $this->detectErrorSpike($events);
        if ($errorSpike) {
            $patterns[] = $errorSpike;
        }
        
        // Detect performance degradation
        $perfDegradation = $this->detectPerfDegradation($events);
        if ($perfDegradation) {
            $patterns[] = $perfDegradation;
        }
        
        // Detect cascading failures
        $cascading = $this->detectCascadingFailures($events);
        if ($cascading) {
            $patterns[] = $cascading;
        }
        
        return $patterns;
    }
}

Create Timeline Visualization

# Incident Timeline: INC-1234

## Date: 2025-01-15
## Duration: 14:00 - 14:55 (55 minutes)
## Impact: 20% checkout failures

## Timeline

| Time | Event | Source | Impact |
|------|-------|--------|--------|
| 14:00 | Deployment started | Git | None |
| 14:05 | Code deployed | Deploy | None |
| 14:10 | Cache cleared | Redis | Performance |
| 14:15 | Errors start | App | Users |
| 14:20 | Alerts triggered | Monitoring | Team |
| 14:25 | Team notified | PagerDuty | Response |
| 14:30 | Investigation started | Team | Resolution |
| 14:35 | Root cause found | Analysis | Fix |
| 14:40 | Rollback initiated | Deploy | Fix |
| 14:45 | Rollback completed | Deploy | Resolution |
| 14:50 | System verified | Testing | Confirmation |
| 14:55 | Incident resolved | Team | None |

## Key Events

### Trigger
- 14:05: Code deployment

### Contributing Factors
- 14:10: Cache cleared (removed warm cache)
- 14:15: New code had performance issue

### Resolution
- 14:40: Rollback to previous version

## Lessons Learned
1. Need better pre-deployment testing
2. Cache clearing caused cold start
3. Monitoring detected issue quickly

Document Findings

// Timeline analysis document
class TimelineDocument
{
    public function create($timeline, $correlations, $patterns)
    {
        return [
            'summary' => $this->createSummary($timeline),
            'timeline' => $timeline,
            'correlations' => $correlations,
            'patterns' => $patterns,
            'trigger' => $this->identifyTrigger($timeline),
            'contributing_factors' => $this->identifyContributingFactors($timeline),
            'resolution' => $this->identifyResolution($timeline),
            'lessons_learned' => $this->extractLessons($timeline, $patterns)
        ];
    }
}