Write path

The picture below explains what happens after a written request is directed to a specific node. Please note the proposed designs for write/read paths are primarily based on the architecture of Cassandra.

1. The write request is persisted on a commit log file.

2. Data is saved in the memory cache.

3. When the memory cache is full or reaches a predefined threshold, data is flushed to SSTable on disk. Note: A sorted-string table (SSTable) is a sorted list of <key, value> pairs. For readers interested in learning more about SStable, refer to the reference material