The article examines how to implement read/unread status for single and group chats at scale, comparing a simple last‑read‑ID approach for one‑on‑one conversations with database, Redis hash, and bitmap‑watermark solutions for groups, and discusses their performance and memory trade‑offs.
The article analyzes the memory inefficiency of storing per‑user read/unread lists for group chat messages, proposes a bitmap‑based solution with user‑to‑map ID mapping, discusses handling of member exits, and evaluates the storage savings and scalability of the new design.
The article analyzes the memory overhead of naïvely storing per‑user read/unread lists for group chat messages and proposes a bitmap‑based scheme with user‑to‑map ID mapping, quit flags, and compact storage that can reduce per‑message space by over 95 percent.
The article examines how to efficiently store read/unread status for group chat messages by replacing per‑user lists with compact bitmap structures, discusses handling member exits, presents C++‑style struct definitions, and quantifies storage savings compared to the naïve 8‑byte per‑user approach.
The article analyzes the memory inefficiency of storing per‑message read/unread user lists in large group chats and proposes a bitmap‑based solution that maps users to sequential IDs, uses compact bitmaps for read status and handles member exits, achieving over 95% storage reduction.
