How do I convert a unix timestamp in int to a `timestamp in KDB?

Question

I'm receiving unix msec timestamps of the form 1673240400000.

How do I convert these to native KDB timestamps?

I've tried various versions of

"P"$ string (1673240400000 % 1000)

But none of these seem to work. I was sure there was a built-in for this?

Answer 1

You need to account for the different epochs.

• Unix 1970
• kdb 2000

Also multiply by 1 million to get nanoseconds

q)epochOffset:`long$1970.01.01D0
q)epochOffset
-946684800000000000
q)`timestamp$epochOffset+1673240400000*1000000
2023.01.09D05:00:00.000000000