- ElastiCache is a web service that makes it easy to deploy, operate and scale in-memory cache in the cloud.
- ElastiCache improves the performance of the application by allowing retrieving the information from the fast, managed in-memory cache then the slow disk based database.
- ElastiCache can improve the latency and throughput for the read-heavy application workloads or compute intensive work loads.
- Caching improves application performance by storing critical piece of data in memory for low latency access.
- ElastiCache has to be used with RDS
- ElastiCache is very good choice if your database is particularly read-heavy and not prone to frequent change.
- Redshift is very good for OLAP transactions.
Types of ElastiCache
- MemCached
- A widely adapted memory objects cache system. ElastiCache protocol is complaint with the MemCached.
- All tools that work with MemCached environments will work in ElastiCache.
- MemCache supports Multi-thread
- MemCache doesnt have Multi-AZ capacity
- Redis
- A popular open-source in-memory key–value store that supports data structure such as sorted sets and list.
- It supports Sorted set and list.
- ElastiCache supports Master-Slave replication and Multi AZ which can be achieve cross AZ redundancy
Caching Strategy
Two types of strategies are available
- Lazy loading
- Write Throughput
Lazy Loading
- Loads the data in cache only when required.
- If the data is in cache, Elastic Cache will return the data or else it will return Null.
- Lazy loading with TTL
- Specify the number of seconds until the key or data expires to avoid keeping stale data in cache.
- Lazy Loading treats an expired key as a cache miss and causes the application to retrieve the data from the database and write it back to the cache with a new TTL.
- Lazy Loading does not eliminate the stale data but to avoid the stale data.
Write Through Cache
Write Through Cache adds and updates the cache whenever the data is written to the database.
