[
https://issues.apache.org/jira/browse/FLINK-39700?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18081834#comment-18081834
]
Arvid Heise commented on FLINK-39700:
-------------------------------------
Nested columns are modeled as a Modify(Physical)ColumnType as before. I'm
certain that we don't have any TableChange class that notifies specifically
about a subcolumn being adjusted.
> Fix name-based column matching in materialized table schema diff
> ----------------------------------------------------------------
>
> Key: FLINK-39700
> URL: https://issues.apache.org/jira/browse/FLINK-39700
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / Planner
> Affects Versions: 2.3.0
> Reporter: Arvid Heise
> Assignee: Arvid Heise
> Priority: Major
> Labels: pull-request-available
> Fix For: 2.4.0
>
>
> MaterializedTableUtils.validateAndExtractColumnChanges currently compares
> schemas positionally (by index). This makes it order-sensitive: if physical
> DDL columns appear in a different order between the old and new schema, the
> diff produces spurious ModifyPhysicalColumnType changes or incorrect
> validation errors. Since DDL column order is arbitrary, the comparison should
> be name-based.
> Additionally, when a physical column has a type change and a comment change
> at the same time, only ModifyPhysicalColumnType is emitted. The comment
> change is silently dropped because the early continue skips the
> comment-comparison block.
> Fix:
>
>
> 1. Build a Map<String, Column> from the old schema and match new columns by
> name, treating unmatched columns as additions or drops.
> 2. After emitting ModifyPhysicalColumnType, check whether the comment also
> changed before continuing.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
