Based on the official documentation from TDengine website:
KEEP is how long the data of the database is kept, the default is 3650 days (10 years), and the database will automatically delete the data expired;
I created a database using following SQL: create database test keep 15. but I found the data older than 15 days still can be displayed by using select query. Anyone knows why the expired data is not deleted automatically?
I finally figured this out, the data file may contain both expired data and unexpired data, TDengine database won't delete the data file until all the data expired.