The JusDB Database Engineering Blog

Aurora PostgreSQL offers sub-30-second failover and 15 read replicas but costs more per instance and adds per-I/O pricing. Learn when Aurora's HA wins over RDS simplicity with real cost modeling for 2025.

Redis hit maxmemory and evicted your session keys because the application stored 8KB JSON blobs instead of 200-byte hashes. Learn to audit memory usage, use compact encodings, and configure the right eviction policy.

pg_dump takes 4 hours on your 200GB database. pg_basebackup takes 20 minutes and enables point-in-time recovery to any second. Learn to set up WAL archiving, take base backups, and execute a PITR restore.

OpenSearch (Apache 2.0) and Elasticsearch (EL2/SSPL) have diverged. Compare licensing, security features, AI/ML capabilities, and migration complexity for 2026.

Your PostgreSQL table is 120GB but only contains 40GB of live data. Learn to measure bloat with pgstattuple, understand why autovacuum falls behind, and reclaim space with pg_repack without table locks.

Error 1213 fires 400 times per hour and your application retries hide it. Learn to read SHOW ENGINE INNODB STATUS deadlock output, identify lock ordering violations, and eliminate the patterns causing them.

pg_stat_statements tracks every query's total time, call count, and cache hit ratio. Learn to enable it, find your highest-cost queries, hunt for cache misses, and measure the impact of every optimization.

MySQL 8.4 LTS removes variables, enforces new replication defaults, and ships changed InnoDB settings that can silently break 8.0 configurations. This production checklist covers every item to verify before upgrading.

mysqld_exporter exposes 300+ MySQL metrics for Prometheus. Learn to deploy it, configure essential alerting rules for connection saturation and replication lag, and build production dashboards in Grafana.

EXPLAIN ANALYZE tells you exactly why your PostgreSQL query is slow, but reading its output is a skill most developers never learn. Learn every node type, identify the five worst plan patterns, and fix them.

Your MySQL instance is at 80% CPU and nobody knows which query is responsible. Learn to enable the slow query log, analyze it with pt-query-digest, and fix the top patterns causing CPU and I/O saturation.

Compare Snowflake, ClickHouse, and BigQuery on performance, cost, ecosystem, and real-world use cases