Postgres database startup parameters

SIGTERM

New connections are no longer allowed, but all active sessions are allowed to complete their work normally, closing only after all sessions have finished the task. This is a smart turn off.

SIGINT

No longer allow new connections, send SIGTERM to all active servers (tell them to exit immediately), and then wait for all child processes to exit and shut down the database. This is a quick shutdown.

SIGQUIT

Causes postgres to send SIGQUIT to all child processes and exit immediately (and all child processes exit immediately) without properly shutting down the database system. This is closed immediately. Doing so will result in a recovery at the next startup (by replaying the WAL log). We recommend using this method only in times of emergency.

SIGKILL

Try not to use this option, which will prevent the server from cleaning up shared memory and semaphore resources, so you can only do it manually before starting the server. In addition, SIGKILL kills postgres directly without waiting for it to relay the signal to its child processes, so we also need to kill each independent child process manually.