Reddit — Ad Budget Pacing in 30ms
Reddit solved sub-30ms ad budget pacing with Apache Druid, achieving 100% accuracy even during Kafka and Flink outages — replacing failed batch and streaming-to-batch approaches.
Scale
Sub-30ms budget decisions against a global shared budget counter across all ad serving
Before
Batch-only and streaming-to-batch approaches causing over-delivery and under-delivery — budgets spent too fast or too slow
After
Apache Druid achieving eventual 100% accuracy even during Kafka or Flink outages
Key Insight
Budget pacing is one of the hardest real-time problems in adtech — you're doing sub-second decisions against a global shared counter. Druid's ability to survive upstream outages while maintaining accuracy is operationally critical.
In a Snowflake Conversation
Budget pacing is one of the hardest real-time problems in adtech — you're doing sub-second decisions against a global shared counter (budget). Druid's ability to survive upstream outages while maintaining accuracy is operationally critical.
My Read
Practitioner commentary coming soon.
Relevant Conversations