Request Latency from Logs¶

Use this query when your app emits request duration values (for example duration_ms=<number>) and you need percentile trends.

Data Source¶

Query Pipeline¶

flowchart LR
    A[Filter by app] --> B[Parse duration field] --> C[Summarize p50 and p95] --> D[Trend by time bin]

Query¶

let AppName = "my-container-app";
ContainerAppConsoleLogs_CL
| where ContainerAppName_s == AppName
| where Log_s has "duration_ms="
| parse Log_s with * "duration_ms=" duration:long *
| summarize p50=percentile(duration, 50), p95=percentile(duration, 95), p99=percentile(duration, 99), max=max(duration) by bin(TimeGenerated, 5m), RevisionName_s
| order by TimeGenerated desc

Example Output¶

Interpretation Notes¶

• Rising p95 with flat replica count suggests scaling constraints.
• Compare p95 and p99 to identify tail latency risk.
• Normal pattern: stable percentiles within SLO band.

Limitations¶

• Depends on consistent log format.
• Parsing fails if duration string format changes.

See Also¶

• Scaling Events
• HTTP Scaling Not Triggering Playbook