How to fix Command timed out in Redis

const Redis = require('ioredis');

const redis = new Redis({
  host: 'localhost',
  port: 6379,
  commandTimeout: 5000,  // Default is undefined (no timeout)
  // Increase to 10 seconds if needed
  commandTimeout: 10000,
});

const redis = new Redis({
  host: 'localhost',
  port: 6379,
  // Limit retries to fail faster
  maxRetriesPerRequest: 3,

  // Or set to null to retry indefinitely (not recommended for most cases)
  // maxRetriesPerRequest: null,
});

# Connect to Redis CLI
redis-cli

# Check slow log for commands taking too long
SLOWLOG GET 10

# Check current connections and memory
INFO stats
INFO memory

# Monitor commands in real-time
MONITOR

// BAD: KEYS blocks Redis
const keys = await redis.keys('user:*');

// GOOD: SCAN doesn't block
const stream = redis.scanStream({
  match: 'user:*',
  count: 100,
});

const keys = [];
stream.on('data', (resultKeys) => {
  keys.push(...resultKeys);
});

stream.on('end', () => {
  console.log('All keys:', keys);
});

const Redis = require('ioredis');

// For standalone Redis
const redis = new Redis({
  host: 'localhost',
  port: 6379,
  enableOfflineQueue: false,  // Fail fast if disconnected
  connectTimeout: 10000,       // 10 seconds to establish connection
  commandTimeout: 5000,        // 5 seconds for command execution
  retryStrategy(times) {
    const delay = Math.min(times * 50, 2000);
    return delay;
  },
});

// For cluster mode
const cluster = new Redis.Cluster(
  [{ host: 'redis-1', port: 6379 }],
  {
    redisOptions: {
      commandTimeout: 5000,
    },
    clusterRetryStrategy(times) {
      return Math.min(100 * times, 2000);
    },
  }
);

# Test network latency
ping your-redis-host

# Test Redis response time
redis-cli -h your-redis-host --latency

# Test continuous latency
redis-cli -h your-redis-host --latency-history

# Check for packet loss
redis-cli -h your-redis-host --latency-dist

const Redis = require('ioredis');

const redis = new Redis({
  host: 'localhost',
  port: 6379,
  commandTimeout: 5000,
  maxRetriesPerRequest: 3,
});

// Handle timeout errors
async function getWithRetry(key, maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return await redis.get(key);
    } catch (error) {
      if (error.message.includes('Command timed out')) {
        console.log(`Retry ${i + 1}/${maxRetries} for key: ${key}`);
        if (i === maxRetries - 1) throw error;
        // Wait before retry
        await new Promise(resolve => setTimeout(resolve, 100 * (i + 1)));
      } else {
        throw error;
      }
    }
  }
}

// Use circuit breaker pattern for resilience
redis.on('error', (error) => {
  console.error('Redis error:', error);
});

# Check current Redis configuration
redis-cli CONFIG GET save
redis-cli CONFIG GET appendonly

# Disable persistence if you don't need durability (cache use case)
redis-cli CONFIG SET save ""
redis-cli CONFIG SET appendonly no

# Or tune persistence for better performance
# Background save every 5 minutes if at least 100 keys changed
redis-cli CONFIG SET save "300 100"

# Use appendfsync everysec instead of always for better performance
appendfsync everysec

# Enable background rewrite
no-appendfsync-on-rewrite yes