Keycloak commits the login INSERT with synchronous_commit off, so a crash loses whole sessions and not just refresh timestamps. Measured 4 of 153 lost, matching the default wal_writer_delay window.
Two injections failed silently first: --grace-period=0 --force lets the container runtime send SIGTERM so PostgreSQL flushes and shuts down cleanly, and SIGKILL to PID 1 from inside its own namespace is ignored by the kernel. Killing a backend makes the postmaster reinitialize, which is a real crash recovery.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
