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Cardinality

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Architecture & Thinking
Architecture & Thinking
Nov 8, 2022 · Databases

Mastering Redis HyperLogLog: Efficient Cardinality Estimation for Big Data

This article explains Redis HyperLogLog, its underlying principles, memory efficiency, typical use cases like UV/PV counting, and provides practical command examples (PFADD, PFCOUNT, PFMERGE) to perform high‑performance cardinality estimation on massive datasets.

Big DataCardinalityDatabase
0 likes · 9 min read
Mastering Redis HyperLogLog: Efficient Cardinality Estimation for Big Data
Code Ape Tech Column
Code Ape Tech Column
Jan 19, 2022 · Databases

Choosing Appropriate Redis Data Structures for Large‑Scale Statistics: Cardinality, Sorting, and Aggregation

This article explains how to select Redis data structures such as Bitmap, HyperLogLog, Set, List, Sorted Set, and Hash to efficiently handle massive statistical scenarios like user login status, UV counting, ranking, and set aggregation, while providing concrete command examples and best‑practice recommendations.

AggregationBitMapCardinality
0 likes · 11 min read
Choosing Appropriate Redis Data Structures for Large‑Scale Statistics: Cardinality, Sorting, and Aggregation
Aikesheng Open Source Community
Aikesheng Open Source Community
Apr 7, 2021 · Databases

Understanding MySQL Index Cardinality and Selectivity

This article explains the concept of MySQL index cardinality, how it influences index selectivity, factors that affect cardinality values, methods to view them, and demonstrates with practical examples how different data distributions and query patterns impact the optimizer's execution plans.

CardinalityDatabaseMySQL
0 likes · 11 min read
Understanding MySQL Index Cardinality and Selectivity
Aikesheng Open Source Community
Aikesheng Open Source Community
May 13, 2019 · Databases

Understanding Cardinality and HINT Usage in MySQL Query Optimization

This article explains the concepts of cardinality and HINT in MySQL, demonstrates how inaccurate cardinality can lead to sub‑optimal execution plans, and shows how applying index_merge hints dramatically reduces query cost and row scans for multi‑column predicates.

CardinalityMySQLQuery Optimizer
0 likes · 7 min read
Understanding Cardinality and HINT Usage in MySQL Query Optimization