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https://issues.apache.org/jira/browse/SPARK-21590?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16112274#comment-16112274
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Kevin Zhang commented on SPARK-21590:
-------------------------------------
[~brkyvz] I don' t know the test you illustrated, but according to the source
code (in org.apache.spark.sql.catalyst.expressions.TimeWindow) below and the
logs in the description produced when I use a window like _window($"timestamp",
"1 day", "1 day", "-8 hours")_
{code:java}
if (startTime < 0) {
return TypeCheckFailure(s"The start time ($startTime) must be greater
than or equal to 0.")
}
{code}
As for using `+16 hours` instead of `-8`, I tried it and it seems everything is
ok. But I'm a little confused about the range of the window. i.e. when I use
window("1 day") I' ll get a window like 2017-08-03 08:00 - 2017-08-04 08:00,
according to my understanding, providing a '+16' start time I will have a
window like 2017-08-04 00:00 - 2017-08-05 00:00 (that is the window of the next
day), but I get the window like 2017-08-03 00:00 - 2017-08-04 00:00, which is
exactly the same as providing '-8', is there something wrong?
> Structured Streaming window start time should support negative values to
> adjust time zone
> -----------------------------------------------------------------------------------------
>
> Key: SPARK-21590
> URL: https://issues.apache.org/jira/browse/SPARK-21590
> Project: Spark
> Issue Type: Bug
> Components: Structured Streaming
> Affects Versions: 2.0.0, 2.0.1, 2.1.0, 2.2.0
> Environment: spark 2.2.0
> Reporter: Kevin Zhang
> Labels: spark-sql, spark2.2, streaming, structured, timezone,
> window
>
> I want to calculate (unique) daily access count using structured streaming
> (2.2.0).
> Now strut streaming' s window with 1 day duration starts at
> 00:00:00 UTC and ends at 23:59:59 UTC each day, but my local timezone is CST
> (UTC + 8 hours) and I
> want date boundaries to be 00:00:00 CST (that is 00:00:00 UTC - 8).
> In Flink I can set the window offset to -8 hours to make it, but here in
> struct streaming if I set the start time (same as the offset in Flink) to -8
> or any other negative values, I will get the following error:
> {code:java}
> Exception in thread "main" org.apache.spark.sql.AnalysisException: cannot
> resolve 'timewindow(timestamp, 86400000000, 86400000000, -28800000000)' due
> to data type mismatch: The start time (-28800000000) must be greater than or
> equal to 0.;;
> {code}
> because the time window checks the input parameters to guarantee each value
> is greater than or equal to 0.
> So I'm thinking about whether we can remove the limit that the start time
> cannot be negative?
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