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https://issues.apache.org/jira/browse/FLINK-22354?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17325768#comment-17325768
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Jark Wu commented on FLINK-22354:
---------------------------------
[~twalthr], I think we can't provide batch&streaming unified/consistent result
for ingestion-time and processing-time. So I think {{CURRENT_ROW_TIMESTAMP}} or
{{CURRENT_TIMESTAMP}} doesn't make big difference if using batch mode.
Besides, we can't use {{PROCTIME()}} for this purpose, because it will be a
processing-time window. The core differences between ingestion-time and
processing-time is where the time is materialized. Ingestion-time is useful in
some cases, for example, cascading window aggreation, because the second
processing-time windows will re-calculate assigned windows according to
wall-clock instead of the window rowtime/proctime.
> Failed to define watermark on computed column of CURRENT_TIMESTAMP and
> LOCALTIMESTAMP
> -------------------------------------------------------------------------------------
>
> Key: FLINK-22354
> URL: https://issues.apache.org/jira/browse/FLINK-22354
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / API
> Reporter: Jark Wu
> Assignee: Leonard Xu
> Priority: Blocker
> Fix For: 1.13.0, 1.14.0
>
>
> It is very common to define watermarks on {{localtimestamp}} and
> {{current_tiemstamp}} to support *ingestion time*. However, the following
> DDLs failed in v1.13. I also tested the following DDLs can pass in v1.12.1,
> so this is a regression.
> The root cause may be introduced by FLINK-21435 which adds a [strict check to
> only allow precision =
> 3|https://github.com/apache/flink/blob/f51168041512b0473decabb2088c1ff4fa4f34bc/flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/catalog/DefaultSchemaResolver.java#L225]
> (precision = 0 should also can be time attribute), however the precision of
> return type of {{current_timestamp}} and {{localtimestamp}} are 0 (another
> long-lived bug). We should fix them both.
> {code:sql}
> Flink SQL> create table datagen_source (
> > order_number BIGINT,
> > price int,
> > buyer string,
> > ts as current_timestamp,
> > proctime as proctime(),
> > watermark for ts as ts - interval '0.001' second
> > ) with (
> > 'connector' = 'datagen',
> > 'rows-per-second' = '1'
> > );
> [ERROR] Could not execute SQL statement. Reason:
> org.apache.flink.table.api.ValidationException: Invalid data type of time
> field for watermark definition. The field must be of type TIMESTAMP(3) or
> TIMESTAMP_LTZ(3).
> Flink SQL> create table datagen_source (
> > order_number BIGINT,
> > price int,
> > buyer string,
> > ts as cast(current_timestamp as timestamp_ltz(3)),
> > proctime as proctime(),
> > watermark for ts as ts - interval '0.001' second
> > ) with (
> > 'connector' = 'datagen',
> > 'rows-per-second' = '1'
> > );
> [INFO] Execute statement succeed.
> Flink SQL> create table datagen_source2 (
> > order_number BIGINT,
> > price int,
> > buyer string,
> > ts as localtimestamp,
> > proctime as proctime(),
> > watermark for ts as ts - interval '0.001' second
> > ) with (
> > 'connector' = 'datagen',
> > 'rows-per-second' = '1'
> > );
> [ERROR] Could not execute SQL statement. Reason:
> org.apache.flink.table.api.ValidationException: Invalid data type of time
> field for watermark definition. The field must be of type TIMESTAMP(3) or
> TIMESTAMP_LTZ(3).
> {code}
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