Oracle Listener Health Check: Preventing Silent Production Outages

This guide explains how Oracle Listener failures silently impact production systems

⏱️ Estimated Reading Time: 14 minutes

Oracle Listener Health Check

It’s 2 AM. Your phone lights up with alerts. Applications are down, dashboards are red, and every connection attempt fails with TNS-12541: TNS:no listener. The database is up — but the business is still dead.

In real production environments, a failed Oracle Listener can block thousands of users, cause SLA breaches, and trigger revenue loss within minutes. We’ve seen P99 login latency jump from milliseconds to total outages.

This guide shows how to implement a production-grade Oracle Listener health check using scripts, monitoring logic, and automation — before the listener becomes your single point of failure.

Oracle 9i on Solaris: A Production Case Study from the Pre-Cloud Era

⏱️ Estimated Reading Time: 12-13 minutes

Oracle 9i on Solaris Case Study (A Deep Dive Retro)

In the early 2000s, database outages were not masked by load balancers, auto-scaling groups, or managed cloud services. If an Oracle database went down on Solaris, the business felt it immediately.

There was no RAC, no ASM, no cloud snapshots. Every failure meant manual diagnosis, filesystem checks, kernel tuning, and long recovery windows. Downtime translated directly into revenue loss and SLA breaches.

This case study revisits a real-world Oracle 9i on Solaris production environment, breaking down architecture decisions, tuning practices, failures, and the lessons modern DBAs can still apply today.

Patroni Failover Testing: The Part Everyone Skips (Until Production Breaks)

⏱️ Estimated Reading Time: 11-12 minutes

Patroni Failover Test Scripts (Part 2 of the Patroni Series)

Your Patroni cluster looks healthy. Primary is up, replicas are streaming, and applications are connected. But the real question is simple: have you ever tested failover?

In production, untested failover is worse than no failover. A broken promotion, stale replication slot, or delayed leader election can turn a simple node crash into minutes of complete outage.

This guide provides real Patroni failover test scripts used by production DBAs to validate leader election, replica promotion, and client recovery — before incidents happen.