linshangquan created FLINK-35318:
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Summary: incorrect timezone handling for
TIMESTAMP_WITH_LOCAL_TIME_ZONE type during predicate pushdown
Key: FLINK-35318
URL: https://issues.apache.org/jira/browse/FLINK-35318
Project: Flink
Issue Type: Bug
Components: Table SQL / API
Affects Versions: 1.16.1
Environment: flink version 1.16.1
iceberg version 1.14.3
Reporter: linshangquan
Attachments: image-2024-05-09-14-06-58-007.png,
image-2024-05-09-14-09-38-453.png, image-2024-05-09-14-11-38-476.png
In our scenario, we have an Iceberg table that contains a column named 'time'
of the {{timestamptz}} data type. This column has 10 rows of data where the
'time' value is {{'2024-04-30 07:00:00'}} expressed in the "Asia/Shanghai"
timezone.
!image-2024-05-09-14-06-58-007.png!
We encountered a strange phenomenon when accessing the table using
Iceberg-flink.
When the {{WHERE}} clause includes the {{time}} column, the results are
incorrect.
ZoneId.{_}systemDefault{_}() = "Asia/Shanghai"
!image-2024-05-09-14-09-38-453.png!
When there is no {{WHERE}} clause, the results are correct.
During debugging, we found that when a {{WHERE}} clause is present, a
{{FilterPushDownSpec}} is generated, and this {{FilterPushDownSpec}} utilizes
{{RexNodeToExpressionConverter}} for translation.
!image-2024-05-09-14-11-38-476.png!
When {{RexNodeToExpressionConverter#visitLiteral}} encounters a
{{TIMESTAMP_WITH_LOCAL_TIME_ZONE}} type, it uses the specified timezone
"Asia/Shanghai" to convert the {{TimestampString}} type to an {{Instant}} type.
However, the upstream {{TimestampString}} data has already been processed in
UTC timezone. By applying the local timezone processing here, an error occurs
due to the mismatch in timezones.
Whether the handling of {{TIMESTAMP_WITH_LOCAL_TIME_ZONE}} type of data in
{{RexNodeToExpressionConverter#visitLiteral}} is a bug, and whether it should
process the data in UTC timezone.
Please help confirm if this is the issue, and if so, we can submit a patch to
fix it.
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