Redis Observability

Redis Observability

What to watch, what to run, and what to alert on. Covers the metrics every Redis deployment should monitor and the built-in commands for ad-hoc diagnosis.

When to apply

• Setting up monitoring or alerts for a Redis instance.
• Diagnosing a Redis performance regression (high latency, memory pressure, connection storms).
• Profiling a slow FT.SEARCH or pipeline.
• Wiring Redis metrics into Prometheus, Datadog, CloudWatch, or similar.

1. Monitor these metrics

These come from INFO and should be exported to your monitoring system.

| Metric | What it tells you | Alert when |

|---|---|---|

| used_memory | Current memory usage | > 80% of maxmemory |

| connected_clients | Open connections | Sudden spikes or drops |

| blocked_clients | Clients waiting on blocking ops | > 0 sustained |

| instantaneous_ops_per_sec | Current throughput | Significant drops |

| keyspace_hits / keyspace_misses | Cache hit ratio | Hit ratio < 80% |

| rejected_connections | Hit maxclients cap | > 0 |

| rdb_last_save_time | Last persistence snapshot | Too old vs. RPO |

info = redis.info()
hit_ratio = info["keyspace_hits"] / max(1, info["keyspace_hits"] + info["keyspace_misses"])
print(f"Memory:    {info['used_memory_human']}")
print(f"Clients:   {info['connected_clients']}")
print(f"Ops/sec:   {info['instantaneous_ops_per_sec']}")
print(f"Hit ratio: {hit_ratio:.1%}")

See references/metrics.md.

2. Built-in commands for debugging

Reach for these when something looks off.

| Topic | Command |

|---|---|

| Slow commands | SLOWLOG GET 10 / SLOWLOG LEN / SLOWLOG RESET |

| Server snapshot | INFO all (or INFO memory / INFO stats / INFO clients / INFO replication) |

| Memory diagnostics | MEMORY DOCTOR / MEMORY STATS / MEMORY USAGE <key> |

| Connections | CLIENT LIST / CLIENT INFO |

| RQE / Search | FT.INFO <idx> / FT.PROFILE <idx> SEARCH QUERY "..." |

The two most useful for incident triage:

• SLOWLOG GET to find queries that exceeded the slowlog-log-slower-than threshold (10ms by default). The output shows the exact command and duration in microseconds.
• MEMORY DOCTOR for memory pressure — it returns a one-paragraph summary of what's unusual about memory usage right now.

for entry in redis.slowlog_get(10):
    print(f"{entry['duration']}μs  {entry['command']}")

See references/commands.md.

3. Redis Insight

For interactive use (running queries, browsing keys, profiling indexes), Redis Insight is the official GUI. It surfaces the same SLOWLOG / INFO / FT.PROFILE data visually and includes Redis Copilot for natural-language queries. Useful during development and incident response; not a replacement for exporting metrics to your monitoring system.

References

• Redis: Latency monitoring
• Redis Insight