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How ClickHouse Stores a Column: PODArray, the Typed Array, and the Padding Trick

Oct 21, 2026 25 min read Jay Hubbert

Underneath every ClickHouse data type there is exactly one data structure: a flat array of trivially-copyable elements. UInt64 is an array of UInt64. String is a flat character …

ClickhousePerformanceInternalsMemorySimd

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PostgreSQL Uses SIMD to Scan Strings Faster

Aug 14, 2026 45 min read Jay Hubbert

Every string-scanning loop in every database has the same shape: look at one byte, decide something about it, advance. It is the shape we all write because it is obviously correct …

PostgresPerformanceSimdInternals

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