Andreas Költringer created SPARK-28515:
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Summary: to_timestamp returns null for summer time switch dates
Key: SPARK-28515
URL: https://issues.apache.org/jira/browse/SPARK-28515
Project: Spark
Issue Type: Bug
Components: SQL
Affects Versions: 2.4.3
Environment: Spark 2.4.3 on Linux 64bit, openjdk-8-jre-headless
Reporter: Andreas Költringer
I am not sure if this is a bug - but it was a very unexpected behavior, so I'd
like some clarification.
When parsing datetime-strings, when the date-time in question falls into the
range of a "summer time switch" (e.g. in (most of) Europe, on 2015-03-29 at 2am
the clock was forwarded to 3am), the {{to_timestamp}} method returns {{NULL}}.
Minimal Example (using Python):
{{>>> df = spark.createDataFrame([('201503290159',), ('201503290200',)],
['date_str'])}}
{{>>> df.withColumn('timestamp', F.to_timestamp('date_str',
'yyyyMMddhhmm')).show()}}
{{+------------+-------------------+
}}
{{| date_str| timestamp|}}
{{+------------+-------------------+}}
{{|201503290159|2015-03-29 01:59:00|}}
{{|201503290200| null|}}
{{+------------+-------------------+}}
A solution (or workaround) is to set the time zone for Spark to UTC:
{{spark.conf.set("spark.sql.session.timeZone", "UTC")}}
(see e.g. [https://stackoverflow.com/q/52594762)]
Plain Java does not do this, e.g. this works as expected:
{{ SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddhhmm"); Date
parsedDate = dateFormat.parse("201503290201"); Timestamp timestamp = new
java.sql.Timestamp(parsedDate.getTime());}}
So, is this really the intended behaviour? Is there documentation about this?
THX.
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