Writing

Notes from production data systems.

Deep dives on problems I’ve solved in the field: storage formats, query engines, migrations, and the details that only show up at scale.

September 28, 202611 min read
Moving HyperLogLog sketches from BigQuery to ClickHouse without the raw data
How I converted BigQuery’s ZetaSketch HLL++ sketches into ClickHouse uniqCombined64 states by transplanting the registers directly: no rehashing, no raw rows, and counts within HLL’s own noise.
- ClickHouse
- BigQuery
- HyperLogLog
- Data Migration
- Rust
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