otter支持使用pt-online-schema-change工具改表同步吗

我在测试过程中，用pt-online-schema-change改表之后，同步就断了，报下面的错误：

`pid:1 nid:2 exception:setl:com.alibaba.otter.node.etl.select.exceptions.SelectException: java.lang.NullPointerException
at com.alibaba.otter.node.etl.select.selector.MessageParser.parse(MessageParser.java:209)
at com.alibaba.otter.node.etl.select.selector.canal.CanalEmbedSelector.selector(CanalEmbedSelector.java:264)
at com.alibaba.otter.node.etl.select.SelectTask.processSelect(SelectTask.java:236)
at com.alibaba.otter.node.etl.select.SelectTask.access$300(SelectTask.java:94)
at com.alibaba.otter.node.etl.select.SelectTask$1.run(SelectTask.java:208)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.NullPointerException
at com.alibaba.otter.node.etl.select.selector.MessageParser.internParse(MessageParser.java:378)
at com.alibaba.otter.node.etl.select.selector.MessageParser.parse(MessageParser.java:181)
... 9 more
`

Reproduce the synchronization failure after using pt-online-schema-change, then start with MessageParser.java at parse (line 209) and internParse (line 378), following the call from CanalEmbedSelector.java. Determine which schema-change event causes the NullPointerException; done means synchronization continues successfully after the table alteration.

Written by the indexing model from the issue text.