[GitHub] [spark] cloud-fan commented on pull request #38640: [WIP][SPARK-41124][SQL][TEST] Add DSv2 PlanStabilitySuites

[GitBox <gi...@apache.org>]

cloud-fan commented on PR #38640:
URL: https://github.com/apache/spark/pull/38640#issuecomment-1325947062

   > Actually, I'm happy to work on making parquet v2 tables available in a separate ticket/PR if you can give my some guidance.
   
   I tried to do it long time ago but failed as there are some design issues. We need to fully understand the use cases of `CREATE TABLE ... USING v1Source` and see how to make it work for v2 sources:
   1. Just a name mapping, so that people can use table name instead of providing all the data source information every time. JDBC data source is a good example of it.
   2. Schema cache. The data source may have a large cost to infer the data schema and need the Spark catalog to cache it. File source is a good example here.
   
   We also need to think about the semantic of `ALTER TABLE`, `REFRESH TABLE`, `df.write.mode("overwrite").saveAsTable`, etc.
   
   Some code references. For v1 source, we have a rule `FindDataSourceTable` to resolve table with v1 source. For v2 source, we probably should have a similar rule to resolve v2 source to `TableProvider`.


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