Reload Dovecot with thousands of domains.

Hello!, I have a dovecot server configured with about 3k different domains. It worked without problems until SSL certificates has been installed. After increase available RAM and stabilizing the service my current problem is in renewals. Dovecot reload process consumes a lot of memory for every one certificate renewal. The server has enough memory to support reload in most cases, but if server has certain load, reload process throws down the service. I’m using lets encrypt certificates and this process is automated.

Is there any way to reload just one domain/session?