Timezone in Cassandra DB

Question

I am unable to store timestamp in cassandra in the local timezone. My springdata API receives the data from a flat file (populated from a UNIX server). The data is converted into java.util.Date and persisted into a cassandra table on timestamp data type.

But it always gets converted to GMT

String str_data = "13/05/2019 15:38:08";
DateFormat format = new SimpleDateFormat("d/M/yyyy H:m:s", Locale.ENGLISH);
Date timestamp = format.parse(str_data);
format.setTimeZone(TimeZone.getTimeZone("Europe/London"));
System.out.println("Time: "+timestamp);

The output on my java console is correct as below:

Time: Mon May 13 15:38:08 BST 2019

But Cassandra DB is as:

ts
--------------------------------
2019-05-13 14:38:08.000000+0000

What am I doing wrong please?

Version Info: [cqlsh 5.0.1 | Cassandra 3.11.2 | CQL spec 3.4.4 | Native protocol v4]

Answer 1

Timestamps are always stored converted to GMT, and then it's your application responsibility to convert it into correct representation. Internally the timestamp is stored as long number, and converted when displaying.

If you want to get this data formatted correctly in cqlsh, you need to setup your ~/.cassandra/cqlshrc file with time zone information - it's done via timezone configuration parameter, like this:

[ui]
TZ = Europe/London

or setting the TZ environment variable when starting cqlsh.