@astatrial
https://docs.splunk.com/Documentation/SplunkCloud/latest/Search/Aboutrealtimesearches
https://docs.splunk.com/Documentation/Splunk/7.3.0/Alert/DefineRealTimeAlerts
The above will be good reads to start with understanding RT searches and alerts in Splunk.
To answer your ques - Yes, in your case as the data is being injected into splunk all the time, a real time search keeps looking at the incoming steam of data continuously as well.
Now having said that realtime search runs continuously, so having a cron (rerun search at fixed interval) does not make much of a sense. For real-time saved searches, as soon as you click "Save", it will start running and KEEP running.
You'd find that while setting up the alert, you'd not find any Cron setting option on the GUI if you try to set a Real Time alert.
Hope this helps. Let me know.
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