Hello to all, I'd like to discuss an issue with flink-jdbc-connector: https://issues.apache.org/jira/browse/FLINK-31553. Currently, the Dialect/Catalog/TypeMappers, etc. are chosen automatically based on the JDBC connection string prefix. For example, if `jdbc:postgresql://....` is used, then the PostgresDialect/Catalog,etc. is chosen which can be problematic for databases like CrateDB or Cochroach DB which they fully support the PostgreSQL JDBC driver (and therefore use the `jdbc:postgresql://...` connection strings) but internally they don't support the same database/schema structure along with PostgreSQL specific pg_tables, (example pg_cursors, pg_constraints, etc.), and maybe the need different type mapping.
I propose to add some new parameter to the `JdbcCatalog`, which will allow the users to select the Dialect, overriding the automatic url-based decision. I'd propose to just add another method in `JdbcDialectFactory` which resolves the dialect before the `acceptsURL` method which will be the fallback. So if the method is `useDialect(String dialectName)` which will be used first, and if string is null/empty or not a matching Dialect is found, the `acceptsURL` is called as a fallback. I propose that the `dialectName` is something simple like `CrateDB`, `MySQL`, etc. or another option would be the fully qualified name of a dialect, which is then loaded by the class loader. With the latter, users can create their own Dialect which will be loaded and used, without the need to merge this into the upstream flink-jdbc-connector repo. Please let me know what do you think of this proposal, and provide your suggestions. Thank you! -- Marios
