The JusDB Database Engineering Blog

MySQL's EXPLAIN command reveals exactly how the query optimizer plans to execute your SQL — which indexes it will use, how many rows it expects to examine, and where it may sort or create temporary tables.

A production guide to online MySQL schema changes — when to use pt-online-schema-change vs gh-ost vs MySQL 8.0 INSTANT DDL, configuration parameters, the cutover mechanism, and a step-by-step safety playbook.

A production guide to MySQL slow query log — enabling with long_query_time and log_queries_not_using_indexes, analyzing with pt-query-digest, reading EXPLAIN output, and fixing full table scans and N+1 loops.

Optimize MySQL connection management for maximum throughput. Learn connection pooling with HikariCP, ProxySQL load balancing, and thread pool configuration.

MySQL 8.0 finally supports true descending indexes — eliminating the filesort that MySQL 5.7 required when sorting results in descending order. Here's how descending indexes work and when to add them.

A complete guide to PostgreSQL memory configuration and performance tuning, covering shared_buffers, work_mem, effective_cache_size, checkpoint tuning, and autovacuum settings that matter in production.

Most MySQL maintenance tasks still rely on cron, but systemd timers offer better logging, dependency management, and failure handling. Here's how to convert your MySQL maintenance scripts to systemd services.

Performing online schema changes on MySQL tables with triggers is a known pain point — pt-osc creates conflicting triggers, and gh-ost has its own limitations. Here are the safe approaches.

Master PostgreSQL VACUUM and autovacuum configuration for optimal database health. Learn dead tuple management, bloat prevention, and vacuum optimization strategies.

A comprehensive guide to optimizing AWS RDS MySQL performance through infrastructure tuning, parameter configuration, and query optimization

MySQL 8.0 significantly improved geospatial support with SRID-aware columns, spatial reference systems, and accurate geographic distance calculations. Here's how to use it in production.

Choose a current MySQL logical backup tool from measured recovery needs, and migrate legacy mysqlpump jobs and archives without risking production data.