mysql> describe transactions;
+---------------+--------------+------+-----+---------+-------+
| Field         | Type         | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+-------+
| txn_id        | int(11)      | YES  |     | NULL    |       |
| customer_id   | int(11)      | YES  |     | NULL    |       |
| amount        | decimal(5,2) | YES  |     | NULL    |       |
| currency      | varchar(50)  | YES  |     | NULL    |       |
| txn_timestamp | varchar(50)  | YES  |     | NULL    |       |
+---------------+--------------+------+-----+---------+-------+
5 rows in set (0.01 sec)

[2019-01-04 17:09:40,225] INFO JdbcSourceTaskConfig values:
 batch.max.rows = 100
 catalog.pattern = null
 connection.attempts = 3
 connection.backoff.ms = 10000
 connection.password = [hidden]
 connection.url = jdbc:mysql://mysql:3306/demo
 connection.user = connect_user
 dialect.name =
 incrementing.column.name = txn_id
 mode = incrementing
 numeric.mapping = null
 numeric.precision.mapping = false
 poll.interval.ms = 5000
 query = SELECT customer_id, amount, currency, txn_timestamp FROM demo.transactions
 schema.pattern = null
 table.blacklist = []
 table.poll.interval.ms = 60000
 table.types = [TABLE]
 table.whitelist = []
 tables = []
 timestamp.column.name = []
 timestamp.delay.interval.ms = 0
 topic.prefix = mysql-xx
 validate.non.null = false
 (io.confluent.connect.jdbc.source.JdbcSourceTaskConfig)

[2019-01-04 17:09:40,625] ERROR WorkerSourceTask{id=jdbc_source_mysql_xx-0} Task threw an uncaught and unrecoverable exception (org.apache.kafka.connect.runtime.WorkerTask)
java.lang.NullPointerException
 at io.confluent.connect.jdbc.source.TimestampIncrementingCriteria.extractOffsetIncrementedId(TimestampIncrementingCriteria.java:231)
 at io.confluent.connect.jdbc.source.TimestampIncrementingCriteria.extractValues(TimestampIncrementingCriteria.java:189)
 at io.confluent.connect.jdbc.source.TimestampIncrementingTableQuerier.extractRecord(TimestampIncrementingTableQuerier.java:185)
 at io.confluent.connect.jdbc.source.JdbcSourceTask.poll(JdbcSourceTask.java:309)
 at org.apache.kafka.connect.runtime.WorkerSourceTask.poll(WorkerSourceTask.java:244)
 at org.apache.kafka.connect.runtime.WorkerSourceTask.execute(WorkerSourceTask.java:220)
 at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:175)
 at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:219)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.run(FutureTask.java:266)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)