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Columnar Storage & File Formats

Columnar Storage & File Formats

Columnar Storage & File Formats

A single query scanning 500GB of row-oriented data to compute one aggregate column. That's not a hypothetical; it's what teams at scale routinely dealt with before columnar storage became the default. After migrating the same dataset to Parquet, that same query scanned 12GB. Same data, same result, forty times less I/O.

The reason comes down to how bytes are physically arranged on disk. Row-oriented storage k...

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