Section
17 pages
Query Performance
EXPLAIN-driven posts on why MySQL and PostgreSQL queries are slow: indexes, selectivity, non-SARGable predicates, covering indexes, sorts, and CPU.
A 10 Gb Database Filled a 200 Gb Disk and Du Could Not Find the Space
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A Billion Row Versions From One Uncommitted Read Stalled a Mysql Replica
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A Query on a 3 Billion Row Table Took 100 Minutes: One Added Line Made It 40ms
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Clustered vs Non Clustered Index: The Table Is the Index in Mysql
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Collation Drift: The Silent Index Killer
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Database Deadlocks, Part 1: The Patterns
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Database Deadlocks, Part 2: Diagnosis, Retries, and Prevention
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How to Read Explain Analyze: Mysql
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How to Read Explain Analyze: Postgresql
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It's Almost Always the Queries, Part I: Why Metal Doesn't Help
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It's Almost Always the Queries, Part Ii: Troubleshooting Steps
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It's Almost Always the Queries, Part Iii: When the Cpu Is Pegged
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It's Almost Always the Queries, Part Iv: When the Sort Spills
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It's Almost Always the Queries, Part V: Disk Has Two Alarms, Not One
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Non Sargable Predicates: How a Function in Where Kills Your Index
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One Column Added to a Select: 1,020 Page Reads Became 166,667
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Uniqueness and Selectivity: The Two Numbers That Drive Query Plans
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