Concept: How Dataiku Handles and Displays Date & Time¶
Dataiku and Dates¶
In Dataiku, “dates” mean “an absolute point in time”, meaning something that is expressible as a date and time and timezone.
2001-01-20T16:00:00.000+0200 refer to the same point in time (14:00Z is 2pm UTC, and 16:00+0200 is 4pm UTC+2, so 2pm UTC too).
Dataiku Only Displays Dates in UTC¶
If you use the Format Date processor with a proper ISO8601 format, it will temporarily show it as a different time zone, but as soon as you write it out or read it in a chart, it will be in UTC again.
If you use a formatter to format as 16:00+0200 and select the output to be a string, then the string value will be preserved, but it’s not a date anymore.
Dates in SQL¶
A date column in SQL will optionally be read in Dataiku as a Dataiku “date” (i.e. an “absolute point in time”), also known as a “timestamp with time zone” in SQL parlance. When Dataiku reads “2020-02-14” from the SQL table, it has to map it to a time. For that, it assumes that it is corresponding to “midnight,” but which midnight?
On a SQL dataset, Dataiku has an “assumed time zone” setting for this. If you select “Local” as “assumed time zone” in the settings of a recipe’s input SQL dataset, then Dataiku will consider that it is reading “2020-02-14 at midnight in Netherlands” (for example, if your local TZ on your server is Europe/Amsterdam). Dataiku then displays this in UTC, so “2020-02-13T23:00:00Z”. If you want it to show “2020-02-14T00:00:00Z”, you must set the assumed time zone to UTC.
Dataiku instance administrators also can set default assumed time zone values in the connection settings so that the time zone is pre-selected.