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https://issues.apache.org/jira/browse/FLINK-41280?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ramin Gharib reassigned FLINK-41280:
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Assignee: Ramin Gharib
> CAST of a TIMESTAMP before 1970 to DATE or TIME returns a wrong value
> ---------------------------------------------------------------------
>
> Key: FLINK-41280
> URL: https://issues.apache.org/jira/browse/FLINK-41280
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / Planner, Table SQL / Runtime
> Affects Versions: 2.3.0
> Reporter: Ramin Gharib
> Assignee: Ramin Gharib
> Priority: Major
>
> h3. Problem
> {{TimestampToDateCastRule}} generates {{(int) (ts.getMillisecond() /
> 86400000L)}}, and {{DateTimeUtils.timestampWithoutLocalZoneToTime}} computes
> {{ts.getMillisecond() % 86400000L}}. Java rounds both toward zero, so a
> {{TIMESTAMP}} before 1970, which has negative epoch milliseconds, lands on
> the wrong day and on a negative time of day.
> ||Input||{{CAST(... AS DATE)}} expected||actual||{{CAST(... AS TIME)}}
> expected||actual||
> |{{TIMESTAMP '1969-12-31
> 23:00:00'}}|{{1969-12-31}}|{{1970-01-01}}|{{23:00:00}}|{{-3600000}} ms of
> day, not a valid time|
> |{{TIMESTAMP '1969-12-31
> 12:00:00'}}|{{1969-12-31}}|{{1970-01-01}}|{{12:00:00}}|{{-43200000}} ms of
> day, not a valid time|
> The values come from evaluating the generated expression and the helper
> against the 2.3.0 jars. {{TIMESTAMP_LTZ}} to {{DATE}} and {{TIME}} is
> correct, because it converts through {{java.time}}.
> h3. Proposal
> Use {{Math.floorDiv}} in {{TimestampToDateCastRule}} and {{Math.floorMod}} in
> {{DateTimeUtils.timestampWithoutLocalZoneToTime}}.
> h3. Tests
> * Cast rule cases for timestamps before 1970, including the last millisecond
> of 1969-12-31, for {{DATE}} and {{TIME(p)}}.
> * A SQL case on a column value, so the generated code runs rather than a
> folded literal.
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