DBC Driver returns missing COLUMN_SIZE in DatabaseMetaData.getColumns() for VARCHAR columns mapped from Spark/Hive STRING

[ankursaini2006]

Problem Description

When querying tables or inspecting metadata through the Kyuubi JDBC driver using third-party JDBC frameworks (specifically Trino's JDBC connector), operations fail with the following exception:

java.lang.IllegalStateException: column size not present

Root Cause & Investigation

1. In JDBC connector frameworks like Trino's BaseJdbcClient.toColumnMapping(), when mapping Types.VARCHAR (JDBC type code 12), it calls JdbcTypeHandle.getRequiredColumnSize().
2. This expects COLUMN_SIZE in DatabaseMetaData.getColumns() (or ResultSetMetaData.getPrecision()) to be populated.
3. Because the underlying engine column type is Spark/Hive STRING (which has no defined length bound), the Kyuubi JDBC driver reports the JDBC data type as 12 (VARCHAR), but leaves COLUMN_SIZE null or unpopulated.
4. Downstream consumers expecting a standard VARCHAR column size fail with a null/missing field error instead of treating it as unbounded.

Question for the Community

• Should Kyuubi's JDBC driver or server return a default fallback COLUMN_SIZE (e.g., Integer.MAX_VALUE or a configurable max length) for Spark/Hive unbounded STRING types mapped to VARCHAR?
• Is there an existing configuration or ongoing fix in recent Kyuubi releases to handle missing column sizes for string fields in DatabaseMetaData?