Why are the changes needed?

The unified catalog does not support the Iceberg change metadata table syntax, which makes it impossible to support the create_changelog_view stored procedure.

spark-sql> CALL spark_catalog.system.create_changelog_view(
         >   table => 'iceberg_v7.iceberg_overwrite',
         >   options => map('start-snapshot-id','486064778759746866','end-snapshot-id', '1216062697090990172'),
         >   changelog_view => 'my_changelog_view_4'
         > );
ANTLR Tool version 4.9.3 used for code generation does not match the current runtime version 4.8ANTLR Runtime version 4.9.3 used for parser compilation does not match the current runtime version 4.8ANTLR Tool version 4.9.3 used for code generation does not match the current runtime version 4.8ANTLR Runtime version 4.9.3 used for parser compilation does not match the current runtime version 4.8
Error in query: spark_catalog requires a single-part namespace, but got [iceberg_v7, iceberg_overwrite]

Brief change log

• add changes subtablename in class IcebergSparkFormat

Apart from this, I haven't found any other situations that need to be addressed. As the version upgrades, it will be necessary to align with the list of subTables supported by Iceberg.

How was this patch tested?

• Add some test cases that check the changes thoroughly including negative and positive cases if possible

• Add screenshots for manual tests if appropriate

• Run test locally before making a pull request

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)