Q:

How DolphinDB clears historical data from distributed tables?

I am using DolphinDB to store real-time metrics generated by factory device. There are 1000 devices, each device generates 3000 metrics per second. I've build a distributed database in DolphinDB to store and analyze these data:
db1 = database (, VALUE, 2013.01.01... 2018.12.31)
db2 = database (, RANGE, 1000* (1.10))
db = database ("dfs://DevMetricsDB", COMPO, [db1, db2])
db.createPartitionedTable(t, "metricsTb", `timestamp` devId)

Since the server disk capacity is not enough to store data for more than a month, I am going to do a scheduled task to backup and delete data from the current database a month ago. I found that DolphinDB distributed tables do not support 'delete' data. What should I do? Can DolphinDB do this? Or do I need shell scripts to do this?

A:

Please use function dropPartition to delete historical data.
db = database ("dfs://DevMetricsDB")
start = today() - 40
end = today() - 30
dropPartition(db, start..end)

