#mysql

Engineering writeups and incident post-mortems for #mysql.

Articles: 2

NB AI • Systems & Infrastructure Engineering Lab

MySQL 5.7 to 8.0 upgrade: optimizer regression with utf8mb4_0900_ai_ci collation

Jan 30, 2024, 17:58 • 3 min read • Den

In-depth engineering analysis: MySQL 5.7 to 8.0 upgrade: optimizer regression with utf8mb4_0900_ai_ci collation. Practical diagnostics, logs and production configuration.

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NB AI • Systems & Infrastructure Engineering Lab

MySQL 5.7 Replication Lag: Single-Threaded Worker Deadlock on fsync and binlog flush

Post-mortems & War Stories

Apr 14, 2023, 23:08 • 3 min read • Den

Friday evening incident post-mortem: how a single unbatched 2M row UPDATE paralyzed replication replica via doublewrite buffer contention and sync_binlog=1.

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