otter source code analysis - (1) debug node source code

To solve a source code question, you need the debug otter node module.

After the synchronization task is enabled, the mainstem of the local node always displays: Positioning, after the data is changed, the synchronization function is unavailable.

 

 

The bug information is as follows

pid:8 nid:3 exception:canal:test_cancal_debug:java.lang.NullPointerException 

at com.alibaba.otter.canal.parse.inbound.mysql.MysqlConnection.loadBinlogChecksum(MysqlConnection.java:284) 

at com.alibaba.otter.canal.parse.inbound.mysql.MysqlConnection.dump(MysqlConnection.java:113) 

at com.alibaba.otter.canal.parse.inbound.AbstractEventParser$3.run(AbstractEventParser.java:209) 

at java.lang.Thread.run(Thread.java:745) 

This problem is that the current 1.0.23 version of canal has some problems, refer to https://github.com/alibaba/otter/issues/258

 

I thought of a way: to associate the local canal source code, and then manually fix the canal bug.

The cannal source link is as follows

https://github.com/alibaba/canal

The otter source link is as follows

https://github.com/alibaba/otter

 

The first step is to fix the source code bug

After observation, it turns out that com.alibaba.otter.canal.parse.inbound.mysql.MysqlConnection.loadBinlogChecksum 中

columnValues.get(0) is not empty, make the following modifications

 

 

The second step is to update otter main pom.xml

 

The third step otter all modules execute maven update.

 

Verified by myself, works well.