1. Accurate Metrics
{devday.23}
Christina Zeller & Marcus Crestani
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2. Software Development
Consulting
Trainings
Functional Programming
Functional Software Architecture
active-group.de
funktionale-programmierung.de
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3. Microchip manufacturing
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4. Monitoring
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5. What happened?
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6. Missing data?
Unreliable network?
Erratic monitoring system?
Flawed collection of metrics?
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7. Metrics
Time Metric Duration
0 duration{device=A} 1
0 duration{device=B} 3
1 duration{device=A} 4
1 duration{device=B} 5
2 duration{device=A} 3
2 duration{device=B} 3
3 duration{device=B} 5
4 duration{device=A} 1
4 duration{device=B} 1
5 duration{device=A} 2
5 duration{device=B} 1
6 duration{device=A} 2
6 duration{device=B} 3
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8. Stored in time-series database
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9. Failure rate
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10. Retention policy
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11. Retention policy
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12. Retention policy
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13. Sampling rate
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14. Missing data
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15. Missing data
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16. No failure detected
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17. Missing data
Unavoidable truths:
Networks are unreliable
Storage is limited
Data is missing
Possible mitigation by shaping metrics differently?
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18. Sums and counters
Time Metric (Duration) Duration sum Count
0 duration{device=A} (1) 1 1
0 duration{device=B} (3) 3 1
1 duration{device=A} (4) 5 2
1 duration{device=B} (5) 8 2
2 duration{device=A} (3) 8 3
2 duration{device=B} (3) 11 3
3 duration{device=A} 8 3
3 duration{device=B} (5) 16 4
4 duration{device=A} (1) 9 4
4 duration{device=B} (1) 17 5
5 duration{device=A} (2) 11 5
5 duration{device=B} (1) 18 6
6 duration{device=A} (2) 13 6
6 duration{device=B} (3) 21 7
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19. Stored in time-series database
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20. Rate of increase
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21. Project durations
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22. Failure rate
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23. Sampling rate 2
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24. Rate of increase
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25. Project durations
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26. Higher failure rate
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27. Histograms
Time Metric (Duration) Duration sum Count Failure bucket
0 duration{device=A} (1) 1 1 0
0 duration{device=B} (3) 3 1 0
1 duration{device=A} (4) 5 2 1
1 duration{device=B} (5) 8 2 1
2 duration{device=A} (3) 8 3 1
2 duration{device=B} (3) 11 3 1
3 duration{device=A} 8 3 1
3 duration{device=B} (5) 16 4 2
4 duration{device=A} (1) 9 4 1
4 duration{device=B} (1) 17 5 2
5 duration{device=A} (2) 11 5 1
5 duration{device=B} (1) 18 6 2
6 duration{device=A} (2) 13 6 1
6 duration{device=B} (3) 21 7 2
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28. Sampling rate 1
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29. Sampling rate 2
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30. Project durations
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31. Failure rate with histograms
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32. Takeaway
Always collect metrics!
Check that your metrics match reality!
Always consider missing data!
For duration metrics always use histograms!
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33. Accurate Metrics
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34. What's next
Code readability vs. metrics collection
https://github.com/active-group/active-logger
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35. Accurate Metrics
{devday.23}
Christina Zeller & Marcus Crestani
35