I have rows of data containing an email address, phone, message, and a datetime.The message will be sent to the email address and phone number at the specified datetime. It might also be sent to a webhook URL.
Suppose I have 50 million rows of these data with dates spanning to over a year in the future. And Suppose I want the messages sent the second they're due or even within the minute they're due.
Does Calendly/Google Calendar/Google Meet really check their databases each minute to send those '30minute before' notifications for millions of events? Does Gmail check the database every second if a scheduled email is due? Or is there another way to fire events specified in the database without querying as much?