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Posted to issues@spark.apache.org by "Chenhao Li (Jira)" <ji...@apache.org> on 2023/03/01 18:54:00 UTC
[jira] [Closed] (SPARK-42634) Several counter-intuitive behaviours in the TimestampAdd expression
[ https://issues.apache.org/jira/browse/SPARK-42634?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chenhao Li closed SPARK-42634.
------------------------------
This is a duplicate, created by mistake.
> 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
>
> # 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 |
> +-------------------------------------------------------------+}}
>
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