Mismatch between janusgraph date value and gremlin query result - gremlin

Question

I have some graph data with date type values.
My gremlin query for the date type property is working, but output value is not the date value.
Environment:
Janusgraph 0.3.1
gremlinpython 3.4.3
Below is my example:
Data (JanusGraph): {"ID": "doc_1", "MY_DATE": [Tue Jan 10 00:00:00 KST 1079]}
Query: g.V().has("ID", "doc_1").valueMap("MY_DATE")
Output (gremlinpython): datetime(1079, 1, 16)
The error is 6 days (1079.1.10 -> 1079.1.16).
This mismatch does not occur when the years are above 1600.
Does the timestamp have some serialization/deserialization problems between janusgraph and gremlinpython?
Thanks

Answer 1

There were some issue with Python and dates but I would have them fixed for 3.4.3, which is the version you stated you were using. The issue is described here at TINKERPOP-2264 along with the fix, but basically there were some issues with timezones. From your example data, it looks like you store your date with a timezone (i.e. KST). I'm not completely sure, but I would imagine things would work as expected if the date was stored as UTC.

Answer 2

After some try & search, I found that there are some difference between java Date and python datetime. (Julian vs. Gregorian Calendar)
So I have replaced SimpleDateFormat with JodaTime and got the expected result as below:
Data (Raw): {"ID": "doc_1", "MY_DATE": "1079-1-29"}
Data (JanusGraph): {"ID": "doc_1", "MY_DATE": [Wed Jan 23 00:32:08 KST 1079]}
(I think the JanusGraph uses java Date object internally..)
Query: g.V().has("ID", "doc_1").valueMap("MY_DATE")
Output (gremlinpython): datetime(1079, 1, 29)
Thanks