The JusDB Database Engineering Blog

MySQL wait_timeout, net_read_timeout, innodb_lock_wait_timeout and max_execution_time — production tuning rules and the HikariCP alignment trick that prevents 'communications link failure' errors.

Production MariaDB Galera Cluster: mariabackup-based SST, MaxScale Galera-aware routing, schema-change strategy with TOI vs RSU, and a troubleshooting playbook for the failures that actually take down production.

A practical runbook for database incidents — triage, diagnosis, escalation, and post-mortem for MySQL and PostgreSQL

Decode PostgreSQL wait events to diagnose lock contention, I/O bottlenecks, and CPU pressure in production

MongoDB's Slot-Based Execution (SBE) engine introduced a plan cache memory leak affecting certain MongoDB versions — here's how to detect, mitigate, and fix it.

A critical bug in MongoDB 8.0 (SERVER-97368) affects TTL index behavior — causing documents to persist beyond expiration or delete prematurely. Here's how to detect and mitigate it.

In 2026, more database versions are hitting end-of-life than any year in recent history.

Guide MySQL query execution with optimizer hints. Covers INDEX, NO_INDEX, JOIN_ORDER, MAX_EXECUTION_TIME, and query block naming for subquery hint targeting.

Monitor InnoDB lock contention with performance_schema.data_locks, find blocking transactions, kill them safely, and prevent escalation with short transactions and proper timeouts.

Guide the PostgreSQL query planner with enable_xxx settings, pg_hint_plan extension, and extended statistics for correlated columns. Fix bad plans without rewriting queries.

Harden MySQL user permissions with host-scoped grants, validate_password plugin, account locking, and privilege auditing. Essential for SOC2 and PCI-DSS compliance.

Understand InnoDB crash recovery mechanics and handle edge cases with innodb_force_recovery. Emergency dump procedures and durability settings to prevent future crashes.