Day 5

# RDB (Redis Database Backup)
# Snapshots: saves the dataset to disk at intervals
# Fast to restore, compact file, small performance impact
# Risk: lose data between last snapshot and crash

# AOF (Append Only File)
# Logs every write operation
# More durable, can recover to exact state before crash
# Larger file, slightly slower writes

# In redis.conf:
save 900 1       # RDB: save after 900s if 1 key changed
save 300 10      # save after 300s if 10 keys changed
appendonly yes   # enable AOF
appendfsync everysec  # fsync every second (good balance)

pip install redis

import redis

r = redis.Redis(
    host='localhost',
    port=6379,
    decode_responses=True  # auto-decode bytes to strings
)

r.set('key', 'value')
print(r.get('key'))  # 'value'

# Pipeline: batch commands (one round trip)
pipe = r.pipeline()
pipe.set('a', 1)
pipe.set('b', 2)
pipe.incr('a')
pipe.execute()

# Upstash = fully managed Redis, serverless pricing
# Free tier: 10,000 commands/day
# No server to manage, works in Vercel/Netlify edge functions

# Get UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN
# from upstash.com

# Node.js
npm install @upstash/redis

import { Redis } from '@upstash/redis';
const redis = Redis.fromEnv();
await redis.set('key', 'value');
const val = await redis.get('key');