Storage-Offline 1:1 Chat

• Flowchart

  • Initial design

  • Improve with sequence num

• Storage requirements

  • Initial schema

  • Improved schema: Decouple msg content from sender and receiver

Flowchart

Initial design

Improve with sequence num

Storage requirements

• Requirement1: Query all 1-on-1 conversations a user participates in after a given timestamp.

• Requirement2: For each conversation, load all messages within that conversation created later than a given timestamp.

Initial schema

Improved schema: Decouple msg content from sender and receiver

• Intuition:

  • Even if sender A deletes the message on his machine, the receiver B should still be able to see it

  • Create a message_content table and message_index table