Any database which offers what are called "continuous queries" also solves this problem. I'm glad the ACM Digital Library is open right now, because I can just

Any database which offers what are called "continuous queries" also solves this problem. I'm glad the ACM Digital Library is open right now, because I can just point to: https://dl.acm.org/action/doSearch?AllField=continuous+queries https://dl.acm.org/action/doSearch?AllField=continuous+queri... The work in general purpose streaming grew out of the continuous query work in the early 2000s. Marrying truly general purpose streaming with transactional databases is not a solved problem (as opposed to transactional databases providing streams), but the notion of continuously running database queries has been around for a long time.