What are the reasons to choose paging by message date and what are its advantages?

Paging by message date is often chosen when it is necessary to ensure correct and convenient viewing of messages in chronological order. Main reasons and advantages:

• Natural order: messages are usually displayed in the order of sending time, so paging by date matches user expectations.
• Loading convenience: messages can be loaded starting from the newest or oldest, loading pages as you scroll.
• Avoiding duplication: paging by date makes it easier to avoid receiving the same messages repeatedly, using timestamps as cursors.
• Query optimization: databases efficiently index by date, which speeds up the retrieval of messages for a specific time range.

Example: when loading a chat, you can request the last 20 messages by specifying the date of the last received message to get the next page of older messages.