Skip to main content

Memory and Storage

Miku uses an intelligent storage system based on SQLite to manage data efficiently and independently.

Short-Term Memory (Chat Memory)​

Chat history is stored in the chat_memory.db file.

  • User-Based Isolation: Each user's chat data is separate. User A will not know what User B has said to the bot.
  • History Limit: The bot only remembers a certain number of recent conversation turns (according to the MAX_HISTORY variable) to maintain context without slowing down the system.
  • Resource Management: Attached image data will be automatically deleted after a period of time (TTL) to avoid bloating the database size.

TTL (Time To Live) Mechanism​

The bot has a background process to clean up memory:

  • Delete Inactive Users: If a user does not message the bot for the MEMORY_IDLE_TTL_SECONDS duration, their entire history is cleared.
  • Delete Old Image Data: Only heavy image data blobs are deleted; text content is retained to save space.

Other Databases​

  • ban_control.db: Stores information about users banned from using the bot.
  • callnames.db: Stores personalized nicknames (how the bot and user address each other).

Logging​

The system uses the JSONL (JSON Lines) format to save chat logs (chat_replay.jsonl). This format makes retrieving and reviewing conversations (Replay) extremely fast and easy for administrators.