Database / PostgreSQLHigh Severity
Fixing Redis "OOM command not allowed when used memory > maxmemory"
Fixing Redis "OOM command not allowed when used memory > maxmemory"
Symptoms
- Application crashes unexpectedly
- High latency and unresponsiveness
- Errors in production logs
Root Causes
Resource Exhaustion or Misconfiguration
The system has encountered a resource limitation or an incorrect configuration that prevents normal operation.
// Sample code that reproduces the issue
function leak() {
const arr = [];
while(true) arr.push(new Array(1000));
}Step-by-Step Fixes
Step 1: Identify the Bottleneck
Use profiling tools to inspect the current state of the application.
# Run diagnostic command
top -H -p <PID>Step 2: Apply Configuration Changes
Tune system parameters to handle the required load safely.
// Apply fix
process.env.NODE_OPTIONS='--max-old-space-size=4096';Prevention Tips
- Implement robust monitoring and alerting
- Conduct regular load testing
- Apply resource quotas and limits
Frequently Asked Questions
- Is this issue common in production?
- Yes, especially under sudden traffic spikes or due to long-running memory leaks.
- How can I monitor for this?
- Set up Prometheus and Grafana dashboards for resource tracking.