1.10 Redis Signal Handling

1. Handling SIGTERM and SIGINT

Tell Redis to shut down gracefully.

• If a background child process is saving an RDB file or performing an AOF rewrite, kill that child process.
• If AOF is enabled, call fsync on the AOF file descriptor to flush the disk buffer.
• If RDB is enabled, save the RDB synchronously in a blocking manner.
  • If the RDB cannot be saved, the Redis server keeps running to prevent data loss.
• If the server is a background process, delete the pid file.
• If a Unix domain socket is enabled, delete it.
• Exit with return code 0.

2. Handling SIGSEGV, SIGBUS, SIGFPE, and SIGILL

Redis crashes.

• Generate a bug report in the log file, including a stack trace, dump of registers, and information about the state of clients.
• If the server is a background process, delete the pid file.
• Unregister its own signal handler and send the same signal to itself. This executes the default signal-handling mechanism, such as dumping the core to the file system.

3. What If a Child Process Is Killed?

• If the child process is performing an AOF rewrite, Redis treats this as an error, ignores the AOF file, and restarts the AOF rewrite.
• If the child process is saving an RDB file, Redis:
  • continues serving read commands;
  • returns a MISCONFIG error for all write commands.

4. References

• Redis Signals Handling – Redis