As discussed in RFC-14, this change implements the first phase of JDBC incremental puller.
It consists following changes:
- JdbcSource: This class extends RowSource and implements
fetchNextBatch(Option<String> lastCkptStr, long sourceLimit)
- SqlQueryBuilder: A simple utility class to build sql queries fluently.
- Implements two modes of fetching: full and incremental.
Full is a complete scan of RDBMS table.
Incremental is delta since last checkpoint.
Incremental mode falls back to full fetch in case of any exception.