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https://issues.apache.org/jira/browse/SPARK-42634?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Chenhao Li updated SPARK-42634:
-------------------------------
Description: (was: # When the time is close to daylight saving time
transition, the result may be discontinuous and not monotonic.
We currently have:
{{scala> spark.conf.set("spark.sql.session.timeZone", "America/Los_Angeles")
scala> spark.sql("select timestampadd(second, 24 * 3600 - 1,
timestamp'2011-03-12 03:00:00')").show
+------------------------------------------------------------------------+
|timestampadd(second, ((24 * 3600) - 1), TIMESTAMP '2011-03-12 03:00:00')|
+------------------------------------------------------------------------+
| 2011-03-13 03:59:59|
+------------------------------------------------------------------------+
scala> spark.sql("select timestampadd(second, 24 * 3600, timestamp'2011-03-12
03:00:00')").show
+------------------------------------------------------------------+
|timestampadd(second, (24 * 3600), TIMESTAMP '2011-03-12 03:00:00')|
+------------------------------------------------------------------+
| 2011-03-13 03:00:00|
+------------------------------------------------------------------+}}
In the second query, adding one more second will set the time back one hour
instead. Plus, there is only 23 * 3600seconds from 2011-03-12 03:00:00 to
2011-03-13 03:00:00, instead of 24 * 3600 seconds, due to the daylight saving
time transition.
The root cause of the problem is the Spark code at
https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala#L790
wrongly assumes every day has MICROS_PER_DAY seconds, and does the day and
time-in-day split before looking at the timezone.
2. Adding month, quarter, and year silently ignores Int overflow during unit
conversion.
The root cause is
https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala#L1246.
quantity is multiplied by 3 or MONTHS_PER_YEARwithout checking overflow. Note
that we do have overflow checking in adding the amount to the timestamp, so the
behavior is inconsistent.
This can cause counter-intuitive results like this:
{{scala> spark.sql("select timestampadd(quarter, 1431655764,
timestamp'1970-01-01')").show
+------------------------------------------------------------------+
|timestampadd(quarter, 1431655764, TIMESTAMP '1970-01-01 00:00:00')|
+------------------------------------------------------------------+
| 1969-09-01 00:00:00|
+------------------------------------------------------------------+}}
3. Adding sub-month units (week, day, hour, minute, second, millisecond,
microsecond)silently ignores Long overflow during unit conversion.
This is similar to the previous problem:
{{scala> spark.sql("select timestampadd(day, 106751992,
timestamp'1970-01-01')").show(false)
+-------------------------------------------------------------+
|timestampadd(day, 106751992, TIMESTAMP '1970-01-01 00:00:00')|
+-------------------------------------------------------------+
|-290308-12-22 15:58:10.448384 |
+-------------------------------------------------------------+}}
)
> Several counter-intuitive behaviours in the TimestampAdd expression
> -------------------------------------------------------------------
>
> Key: SPARK-42634
> URL: https://issues.apache.org/jira/browse/SPARK-42634
> Project: Spark
> Issue Type: Bug
> Components: Spark Core, SQL
> Affects Versions: 3.3.0, 3.3.1, 3.3.2
> Reporter: Chenhao Li
> Priority: Major
>
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