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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
Depending on how sophisticated you are with C++ you might want to try to impress him by using multithreading. I like this simple library. It's only like a 100 lines of code in a single header, and it is very simple to use.
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