Perplexity moves core search reads from DynamoDB to CobbleDB
Production batch reads are faster, but the measurements do not establish whether users get search results faster.
Perplexity has shifted core search reads from DynamoDB to CobbleDB, a Rust key-value store designed for batched retrieval of large language-model context; a query can involve 100–120 page keys, and records average about 50 KB. The architecture assigns durable data to Pillar, batch-file preparation to Lorry, and serving lookups to CobbleDB, using Amazon S3 to carry exported payloads. In production, median batch-read latency decreased from 31.4 ms to 5.60 ms, p90 from 56.7 ms to 9.77 ms, and p99 from 123 ms to 24.2 ms; storage costs fell by at least 20%. Tests with payloads up to 100 KB reached 500,000 requests per second, although asynchronous replica updates mean the system accepts some consistency lag. CEO Aravind Srinivas said two systems engineers and AI coding agents built the 40,000-line database in two months, and Perplexity plans to open-source it in a future release.
Why it matters
The change is inside the serving layer behind Perplexity’s core search; the reported read times do not show whether the full search experience is faster for users. Perplexity plans to open-source CobbleDB, which would make the database available beyond the company.
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