Caching

Cache aside pattern

• If data not found in cache, first time get data from data source
• Save data in cache
• Next time use cache data
• Disadvantage in it loads infrequent data also.

Caching Types

• Private Cache
• Shared Cache

Redis

Where should i use caching? or Which data needs to be cached?

The data that is frequently used and doesn't change frequently.

What is Redis and why it is used?

Redis is a key-value data store.

Why Redis is fast?

• Light weight simple architectecure.
• Key- Value Retrival
• In Memory

Azure Redis cache tiers

• Basic
• Standard
• Premium (Only premium tiers supports virtual networks)
• Enterprise
• Enterprise Flash - (This tier extends redis data storage to non volatilememory. Which is cheaper than DRAM on VM, It reduces memory cost)

Azure Redis Evection Policies

Comes into picture when cache reaches memory limit.

Volatile Keys-

Cache keys that have expireation time associated to them are called volatile keys.

Eviction Policies

• No eveiction policy
• All keys - lru (Least recently used)
• All keys - fru
• Volatile keys - lru
• Volatile Keys fru

Persistance models for Azure redis cache

Redis Data Types:

• Strings
• Lists
• Hashes
• Sets
• Sorted Sets

  How to choose between different redis data types?

Redis Keys:

• Binary Safe
• Having very long/short keys is not good idea

Redis CLI

Redis Commands

• Set Key Value
• Get Key
• Scan - for getting more/all

Using Redis in ASP.Net Core

Using IDistributedCache

• Simple
• Restricted data types are allowed.
• Package 'Microsoft.Extensions.Caching.StackExchangeRedis'

Using IConnectionMultiplexer

• All data types are supported
• • Package 'Microsoft.Extensions.Caching.StackExchangeRedis' or 'StackExchange.Redis'

Redis as a Primary DB

Redis does more than acting as a cache like 'Database', 'Message Broker'. Redis offer number of approaches for data persistance. You doesn't loose data if redis restarts.

• Redis as primary DB