4 August 2026 » Alpesh Kumar

The UUID Primary Key Problem That Shows Up at 200 Million Rows — a framed technical comparison shows a random UUID B-tree scattering inserts and a point lookup fanning into many cold row pages, contrasted with a time-ordered UUID path that keeps inserts and fetched pages locally clustered. Visual direction: idea: a UUID primary-key lookup can find the key quickly yet still cause extreme page reads when random insertion order scatters the B-tree and cold row pages; subject: UUID primary keys at 200 million rows; mechanism: compare random UUID insert distribution across many B-tree leaf pages with time-ordered UUID inserts concentrated at the active edge, then show a point lookup descending the index and fanning out into scattered cold data pages marked by a dense 94,000-read texture; composition: framed comparison — a generous title band across the top, with a large left diagnostic zone for random UUID scatter and a right diagnostic zone for ordered UUID locality, joined only at the bottom by one shared lookup-to-row path; palette: deep forest/moss — pale eucalyptus background, forest-green and near-black ink, muted sandstone page blocks, restrained burnt-orange I/O accents, and a small burgundy warning accent; exclusions: dark navy, neon-blue glow, floating UI cards, network nodes, generic AI circuitry, people, robots, hands, dashboards, logos, fake code, secondary readable text, decorative charts, physical-machine metaphors

System Design

The UUID Primary Key Problem That Shows Up at 200 Million Rows

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“ Design is not just what it looks like and feels like. Design is how it works. “

Alpesh Kumar

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