Spark SQL未正确转换时区

问题描述

使用Scala 2.10.4和spark 1.5.1和spark 1.6

Using Scala 2.10.4 and spark 1.5.1 and spark 1.6

sqlContext.sql(
  """
    |select id,
    |to_date(from_utc_timestamp(from_unixtime(at), 'US/Pacific')),
    |from_utc_timestamp(from_unixtime(at), 'US/Pacific'),
    |from_unixtime(at),
    |to_date(from_unixtime(at)),
    | at
    |from events
    | limit 100
  """.stripMargin).collect().foreach(println)

火花提交选项:--driver-java-options '-Duser.timezone=US/Pacific'

结果:

[56d2a9573bc4b5c38453eae7,2016-02-28,2016-02-27 16:01:27.0,2016-02-28 08:01:27,2016-02-28,1456646487]
[56d2aa1bfd2460183a571762,2016-02-28,2016-02-27 16:04:43.0,2016-02-28 08:04:43,2016-02-28,1456646683]
[56d2aaa9eb63bbb63456d5b5,2016-02-28,2016-02-27 16:07:05.0,2016-02-28 08:07:05,2016-02-28,1456646825]
[56d2aab15a21fa5f4c4f42a7,2016-02-28,2016-02-27 16:07:13.0,2016-02-28 08:07:13,2016-02-28,1456646833]
[56d2aac8aeeee48b74531af0,2016-02-28,2016-02-27 16:07:36.0,2016-02-28 08:07:36,2016-02-28,1456646856]
[56d2ab1d87fd3f4f72567788,2016-02-28,2016-02-27 16:09:01.0,2016-02-28 08:09:01,2016-02-28,1456646941]

在美国/太平洋地区的时间应为2016-02-28 00:01:27等，但有些方法是两次将"8"小时相减

The time in US/Pacific should be 2016-02-28 00:01:27 etc but some how it subtracts "8" hours twice

推荐答案

在阅读一段时间后，得出以下结论:

after reading for sometime following are the conclusions:

• Spark-Sql不支持日期时间，也不支持时区
• 使用时间戳是唯一的解决方案
• from_unixtime(at)正确解析时间，只是将其打印为字符串会由于时区而改变.可以肯定地假设from_unixtime将正确地对其进行转换(尽管打印可能会显示不同的结果)
• from_utc_timestamp会将时间戳转换(不只是转换)到该时区，在这种情况下，它将减去自(-08:00)以来的时间8小时.
• 打印sql结果会混淆有关时区参数的时间

• Spark-Sql doesn't support date-time, and nor timezones
• Using timestamp is the only solution
• from_unixtime(at) parses the epoch time correctly, just that the printing of it as a string changes it due to timezone. It is safe to assume that the from_unixtime will convert it correctly ( although printing it might show different results)
• from_utc_timestamp will shift ( not just convert) the timestamp to that timezone, in this case it will subtract 8 hours to the time since (-08:00)
• printing sql results messes up the times with respect to timezone param

这篇关于Spark SQL未正确转换时区的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！