解析create schema日志后，调用不断抛异常

疑问1

场景：启动canal，执行create schema语句，通过 Message getWithoutAck(int batchSize)获得日志数据。当下一次再调用该方法时，抛出以下异常。 如果canal解析create schema日志前，解析了其他语句（crud）的日志，则不会出现这样的错误。

异常信息栈： 2018-10-09 10:19:20.755 [main] ERROR syncLogger - !!!!增量同步异常|com.alibaba.otter.canal.protocol.exception.CanalClientException: something goes wrong with reason: something goes wrong with channel:[id: 0xcf561b9e, /192.168.1.179:50803 => /192.168.1.179:2017], exception=java.lang.NullPointerException at com.alibaba.otter.canal.store.helper.CanalEventUtils.createPosition(CanalEventUtils.java:69) at com.alibaba.otter.canal.store.memory.MemoryEventStoreWithBuffer.getFirstPosition(MemoryEventStoreWithBuffer.java:375) at com.alibaba.otter.canal.store.memory.MemoryEventStoreWithBuffer.getFirstPosition(MemoryEventStoreWithBuffer.java:36) at com.alibaba.otter.canal.server.embedded.CanalServerWithEmbedded.getWithoutAck(CanalServerWithEmbedded.java:307) at com.alibaba.otter.canal.server.embedded.CanalServerWithEmbedded.getWithoutAck(CanalServerWithEmbedded.java:273) at com.alibaba.otter.canal.server.netty.handler.SessionHandler.messageReceived(SessionHandler.java:124) at org.jboss.netty.channel.SimpleChannelHandler.handleUpstream(SimpleChannelHandler.java:88) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791) at org.jboss.netty.channel.SimpleChannelHandler.messageReceived(SimpleChannelHandler.java:142) at org.jboss.netty.channel.SimpleChannelHandler.handleUpstream(SimpleChannelHandler.java:88) at org.jboss.netty.handler.timeout.IdleStateAwareChannelHandler.handleUpstream(IdleStateAwareChannelHandler.java:36) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791) at org.jboss.netty.handler.timeout.IdleStateHandler.messageReceived(IdleStateHandler.java:294) at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:296) at org.jboss.netty.handler.codec.frame.FrameDecoder.unfoldAndFireMessageReceived(FrameDecoder.java:462) at org.jboss.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:536) at org.jboss.netty.handler.codec.replay.ReplayingDecoder.messageReceived(ReplayingDecoder.java:435) at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255) at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:88) at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:109) at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:312) at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:90) at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178) at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) at com.alibaba.otter.canal.client.impl.SimpleCanalConnector.receiveMessages(SimpleCanalConnector.java:344) at com.alibaba.otter.canal.client.impl.SimpleCanalConnector.getWithoutAck(SimpleCanalConnector.java:315) at com.alibaba.otter.canal.client.impl.SimpleCanalConnector.getWithoutAck(SimpleCanalConnector.java:287)

疑问2

另外，create schema语句对应的event type是Query，isDdl=false，感觉不太对。

原提问者GitHub用户DaiZZZZZ