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https://issues.apache.org/jira/browse/FLINK-21715?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-21715:
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Labels: pull-request-available (was: )
> Support implicit cast conversion between timestamp and timestamp_ltz
> ---------------------------------------------------------------------
>
> Key: FLINK-21715
> URL: https://issues.apache.org/jira/browse/FLINK-21715
> Project: Flink
> Issue Type: Sub-task
> Components: Table SQL / API, Table SQL / Runtime
> Reporter: Leonard Xu
> Assignee: Leonard Xu
> Priority: Major
> Labels: pull-request-available
>
> The existed UDFs using `LocalDateTime` or `java.sql.Timestamp` as parameters
> type, if the data type of parameter column in SQL changed from TIMESTAMP to
> TIMESTAMP_LTZ, these UDFs must be rewritten, because TIMESTAMP_LTZ data type
> does not support `LocalDateTime` or `java.sql.Timestamp` as conversion class.
>
> The first approach is to support the two conversion classes for
> TIMESTAMP_LTZ data type, to obtain the correct result, the local time zone
> information is necessary when conversion happens between SQL internal data
> structure `TimestampData` and external conversion class `LocalDateTime` or
> `java.sql.Timestamp`.
> In this approach, after a e2e POC, we found that there are more changes than
> we thought before. It is difficult to cover with tests and it is easy to
> introduce bugs.
>
> Thus, to resolve the UDF compatibility issue, we consider support the
> implicit cast conversion between timestamp and timestamp_ltz after some
> offline discuss with [~jark] and [~ykt836],
> This way is clean and lightweight way to resolve the UDF compatibility issue
> and doesn't change any public interface as well. BTW the implicit cast
> conversion is supported in Oracle[1]
>
> [1]https://docs.oracle.com/cd/B19306_01/server.102/b14225/ch4datetime.htm
>
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