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.

Master PostgreSQL EXPLAIN ANALYZE output: understand node types, cost estimates, actual vs estimated rows, and identify the root cause of slow queries.

Decode MySQL deadlock messages from SHOW ENGINE INNODB STATUS, understand lock ordering, and write application code that eliminates deadlocks permanently.

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.