Write Through

Write through cache is a simple to implement caching mechanism.

• Here the newly arrived data is written into cache and as well as persisted into the disk or a database. Atomicity is maintained.

There are two ways to implement it:
1] The application writes data to cache and database simultaneously

2] The application writes data to cache and then the cache writes the data into the database.

Advantages:

• Simple to implement.
• Faster response times.
• Data integrity because of atomic nature of write operation.
• Lower latency for subsequent reads.

Disadvantages:

• Cache pollution: Since every time the data is filled into cache, it can get filled with less frequently read data and more cache eviction which could introduce some latency.

• Not suitable for write intensive scenarios as the write operations are slower compared to other methods because data needs to be written in cache as well as persistent storage everytime.