Ensuring a consistently great Netflix experience while continuously pushing innovative technology updates is no easy feat. We'll look at how Netflix turns log streams into real-time metrics to provide visibility into how devices are performing in the field. Including sharing some of the lessons learned around optimizing Druid to handle our load.

1. How Netflix Uses Druid in
Real-time to Ensure a High
Quality Streaming
Experience
September 2020
Ben Sykes, Sr Software Engineer, Netflix
1

2. Druid @
Netflix
How Netflix Uses Druid in Real-time to
Ensure a High Quality Streaming
Experience
Druid Summit II - Sep 2020

3. Druid Summit II
Sep 2020
Talking Points
Background
Quality of Experience
Metrics Pipeline
Using Druid
Druid Cluster
Data Ingestion
Managing Performance
Trade-offs
Tools

4. Druid Summit II
Sep 2020
Glossary
Measure
A value relating to an event. E.g. The presence of an error, size of a
buffer, or a duration.
Metric
Meaning and value derived from one or more measures. Counts,
Rates or Percentiles of measured values.
Dimension, Tag
An attribute of a metric that can be used to group or summarize
metrics by populations with shared properties.
Cardinality
The count of unique values of a given dimension.
Segment
An index file used by Druid to contain data for a given time block. A
time block may be formed of multiple segments.

5. Druid Summit II
Sep 2020
Quality of Experience

6. Druid Summit II
Sep 2020
Dashboards &
Monitoring

7. Druid Summit II
Sep 2020
Automated Alerting

8. Druid Summit II
Sep 2020
Automated Canary Analysis

9. Druid Summit II
Sep 2020
Metrics Pipeline

10. Druid Summit II
Sep 2020
Measure Extraction

11. Using Druid
Druid Summit II
Sep 2020

12. Druid Summit II
Sep 2020
Druid Cluster

13. Druid Summit II
Sep 2020
Rollup
Dimensions Metrics

14. Druid Summit II
Sep 2020
Cardinality
Dimensions
Device = { iPhone, Chrome, TV, iPhone, iPhone, TV, iPhone } |Device| = 3
Country = { US, CA, US, CA, CA, US, US } |Country| = 2

15. Druid Summit II
Sep 2020
Segments

16. Druid Summit II
Sep 2020
Realtime Indexing
Per Kafka Topic Many Partitions
Many Indexers per
MiddleManager,
Many Partitions per
Indexer
Many Segments per
Indexer

17. Druid Summit II
Sep 2020
Realtime Indexing
Per Kafka Topic Many Partitions
Many Indexers per
MiddleManager,
Many Partitions per
Indexer
Many Segments per
Indexer

18. Druid Summit II
Sep 2020
Realtime Indexing
Per Kafka Topic Many Partitions
Many Indexers per
MiddleManager,
Many Partitions per
Indexer
Many Segments per
Indexer

19. Druid Summit II
Sep 2020
Realtime Indexing
Per Kafka Topic Many Partitions
Many Indexers per
MiddleManager,
Many Partitions per
Indexer
Many Segments per
Indexer

20. Druid Summit II
Sep 2020
Realtime Indexing
Per Kafka Topic Many Partitions
Many Indexers per
MiddleManager,
Many Partitions per
Indexer
Many Segments per
Indexer
2

21. Druid Summit II
Sep 2020
Managing Performance

22. Druid Summit II
Sep 2020
Compaction
2
4 35 3 4

23. Druid Summit II
Sep 2020
Trade-offs
● Restrict dimensionality
● Limit cardinality (TopN, include list)
● Increase query granularity
● Reduce concurrent query limit
● Over-provision cluster
● Education and context on effects
● Monitor cardinality increases
● Sufficient query granularity
● Fail-fast on overload
● Monitor resources, plan scale
Better Query Performance More Flexibility

24. Druid Summit II
Sep 2020
Measure and Monitor
Cluster Performance

25. Druid Summit II
Sep 2020
Frequent Benchmarks

26. Druid Summit II
Sep 2020
Atlas Lumen
Built on OSS

27. Time for questions
27
Thank you!
Apache Druid is an independent project of The Apache Software Foundation. More information can be found at https://druid.apache.org.
Apache Druid, Druid, and the Druid logo are either registered trademarks or trademarks of The Apache Software Foundation in the United States and other countries.

28. November 2-4, 2020
San Francisco, CA
druidsummit.org
28
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