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https://issues.apache.org/jira/browse/FLINK-13372?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17323214#comment-17323214
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Flink Jira Bot commented on FLINK-13372:
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This issue is assigned but has not received an update in 7 days so it has been
labeled "stale-assigned". If you are still working on the issue, please give an
update and remove the label. If you are no longer working on the issue, please
unassign so someone else may work on it. In 7 days the issue will be
automatically unassigned.
> Timestamp conversion bug in non-blink Table/SQL runtime
> -------------------------------------------------------
>
> Key: FLINK-13372
> URL: https://issues.apache.org/jira/browse/FLINK-13372
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / Runtime
> Affects Versions: 1.6.3, 1.6.4, 1.7.2, 1.8.0, 1.8.1, 1.9.0
> Reporter: Shuyi Chen
> Assignee: Shuyi Chen
> Priority: Critical
> Labels: stale-assigned
>
> Currently, in the non-blink table/SQL runtime, Flink used
> SqlFunctions.internalToTimestamp(long v) from Calcite to convert event time
> (in long) to java.sql.Timestamp.
> {code:java}
> public static Timestamp internalToTimestamp(long v) { return new Timestamp(v
> - (long)LOCAL_TZ.getOffset(v)); } {code}
> However, as discussed in the recent Calcite mailing list,
> SqlFunctions.internalToTimestamp() assumes the input timestamp value is in
> the current JVM’s default timezone (which is unusual), NOT milliseconds since
> epoch. And SqlFunctions.internalToTimestamp() is used to convert timestamp
> value in the current JVM’s default timezone to milliseconds since epoch,
> which java.sql.Timestamp constructor takes. Therefore, the results will not
> only be wrong, but change if the job runs in machines on different timezones
> as well.(The only exception is that all your production machines uses UTC
> timezone.)
> Here is an example, if the user input value is 0 (00:00:00 UTC on 1 January
> 1970), and the table/SQL runtime runs in a machine in PST (UTC-8), the output
> sql.Timestamp after SqlFunctions.internalToTimestamp() will become 28800000
> millisec since epoch (08:00:00 UTC on 1 January 1970); And with the same
> input, if the table/SQL runtime runs again in a different machine in EST
> (UTC-5), the output sql.Timestamp after SqlFunctions.internalToTimestamp()
> will become 18000000 millisec since epoch (05:00:00 UTC on 1 January 1970).
> Currently, there are unittests to test the table/SQL API event time
> input/output (e.g., GroupWindowITCase.testEventTimeTumblingWindow() and
> SqlITCase.testDistinctAggWithMergeOnEventTimeSessionGroupWindow()). They now
> all passed because we are comparing the string format of the time which
> ignores timezone. If you step into the code, the actual java.sql.Timestamp
> value is wrong and change as the tests run in different timezone (e.g., one
> can use -Duser.timezone=PST to change the current JVM’s default timezone)
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