Fix bug that when create jdbc resource with only jdbc driver file name, it will failed to do checksum
This is because we forgot the pass the full driver url to JdbcClient.
Add ResultSet.FETCH_FORWARD and set AutoCommit to false to jdbc connection, so to avoid OOM when fetching large amount of data
set useCursorFetch in jdbc url for both MySQL and PostgreSQL.
Fix some p2 external datasource bug