# MediaTailor ad skipping monitoring and alerts
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Proactive monitoring helps you detect and resolve ad skipping issues before they significantly impact your revenue. AWS Elemental MediaTailor provides comprehensive metrics and logging capabilities that enable effective monitoring of ad insertion performance. This guide explains how to set up effective monitoring for ad skipping issues.

## Key CloudWatch metrics to monitor
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Set up CloudWatch alarms for these key MediaTailor metrics:
+ `AdDecisionServer.Ads.Skipped` - Count of skipped ads
+ `AdDecisionServer.Timeouts` - Count of ADS timeouts
+ `Avail.FilledDuration` - Duration of filled ad breaks
+ `Avail.SlateOnly` - Count of ad breaks filled with slate only

## Advanced CloudWatch Logs Insights queries
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Use these specialized queries for detailed troubleshooting:

### Comprehensive session analysis
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For detailed analysis of ad insertion behavior for a specific session:

```
fields @timestamp, sessionId, eventType, creativeId, skipReason, adBreakIndex
| filter sessionId = "your-session-id-here"
| filter eventType in ["FILLED_AVAIL", "SKIPPED_AVAIL", "MAKING_ADS_REQUEST"]
| sort @timestamp asc
| limit 100
```

### Finding Creative IDs
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To identify Creative IDs from FILLED\$1AVAIL events:

```
fields @timestamp, sessionId, eventType
| filter sessionId like /sessionId/ and eventType!='BEACON_FIRED'
| sort @timestamp desc
```

**Note**  
Replace `sessionId` with the actual session ID you're investigating.