How JD Cloud’s JCHDB Powered the 11.11 Shopping Festival’s Massive Data Surge

During JD's 11.11 shopping festival, JD Cloud's database handled PB‑level data growth, achieving a 258% increase compared to the 618 peak, with total order amount exceeding 271.5 billion yuan, up 33% YoY.

JCHDB, an OLAP service built on ClickHouse, provides a distributed architecture with multi‑core, multi‑node parallel queries, delivering 1‑2 orders of magnitude faster performance than traditional open‑source databases, meeting real‑time analysis needs during large‑scale promotions.

Real‑time order data flows through Kafka and Flink into JCHDB; the system supports batch writes of 50‑200 MB/s, but frequent small‑batch writes during the event required tuning of ZooKeeper JVM parameters and cloud‑disk concurrency to ensure stability.

The team optimized write patterns to favor larger, less frequent batches while maintaining query performance, and adjusted cluster parameters to sustain service under high pressure.

Key operational steps for the 11.11 preparation include: (1) scope identification, (2) traffic estimation, (3) plan drafting, (4) monitoring and alert design, (5) stress testing, (6) rehearsal, (7) on‑call duty, (8) post‑event review.

High‑availability architecture offers single‑zone and multi‑zone deployments, anti‑affinity for primary‑replica, sub‑2 ms replication, and a custom sentinel system for automatic failover.

Fault‑tolerant design enables second‑level automatic switch‑over, ensuring data consistency by replaying logs before VIP switch.

Elastic storage expansion leverages cloud‑disk incremental snapshots, allowing expansion to any size within 3‑5 minutes for cloud‑disk instances and near‑instant vertical scaling for local‑disk instances.

During the “opening red” period, the database peaked at 5.024 million QPS and 1.183 Tbps traffic, demonstrating the effectiveness of the architecture.

Overall, JD Cloud’s database provides end‑to‑end services from provisioning to monitoring, supporting JD Retail, Logistics, AI, Health, and other core businesses, making it a reliable choice for enterprise cloud migration.