Tag: design-system
All the articles with the tag "design-system".
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System Design - How PostgreSQL Index-Only Scans Use the Visibility Map
Why a covering index does not always avoid heap visits: follow one PostgreSQL index-only scan through the visibility map, VACUUM, and EXPLAIN's Heap Fetches counter.
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System Design - How TiDB's UNION ALL Executor Merges Chunks
Trace TiDB's root UnionAllExec from planner to worker goroutines, reusable chunks, error delivery, and the session concurrency knob.
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System Design - How Sagas Coordinate Distributed Transactions
Follow an order through inventory reservation, payment, and compensation to understand what a saga guarantees, what it cannot undo, and how to make retries safe.
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System Design - How TiDB's Projection Executor Runs Expressions
Trace a root TiDB Projection from physical plan to child chunks, expression evaluation, and ordered parallel workers; learn why it sometimes runs sequentially.
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System Design - How TiDB's TopN Executor Keeps Only the Best Rows
Trace ORDER BY with OFFSET and LIMIT through TiDB's PhysicalTopN, executor builder, TopNExec, and chunk heap, including memory and spill settings.
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System Design - How HyperLogLog Counts Distinct Values
Follow a visitor from a hash to a HyperLogLog register, then see how Redis estimates and merges distinct counts without keeping the visitors themselves.