[HBASE-6589] RegionServer can't load class for dynamically loaded coprocessors with self defined class

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Incomplete
• Component/s: Coprocessors, regionserver
• Assignee: Unassigned
• Reporter: ShiXing
• Created: 15/Aug/12 14:44
• Updated: 13/Jun/22 19:02
• Resolved: 13/Jun/22 19:02

Description

When using coprocessor with custom classes like LongColumnInterpreter(mine is MultiColumnSchema), the coprocessor can not work for hot deploy, if the custom classes do not deploy in the regionserver's classpath. Although the self-defined class is deployed in the regions' classpath through hdfs jar.

The exception threw at the regionserver's log:

2012-08-15 16:24:24,403 ERROR org.apache.hadoop.hbase.io.HbaseObjectWritable: Error in readFields
java.io.IOException: Can't find class com.taobao.hbase.coprocessor.MultiColumnSchema
        at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:674)
        at org.apache.hadoop.hbase.client.coprocessor.Exec.readFields(Exec.java:114)
        at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:682)
        at org.apache.hadoop.hbase.ipc.Invocation.readFields(Invocation.java:125)
        at org.apache.hadoop.hbase.ipc.HBaseServer$Connection.processData(HBaseServer.java:1292)
        at org.apache.hadoop.hbase.ipc.HBaseServer$Connection.readAndProcess(HBaseServer.java:1207)
        at org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:735)
        at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.doRunLoop(HBaseServer.java:524)
        at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:499)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.ClassNotFoundException: com.taobao.hbase.coprocessor.MultiColumnSchema
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:247)
        at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:943)
        at org.apache.hadoop.hbase.io.HbaseObjectWritable.getClassByName(HbaseObjectWritable.java:784)
        at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:671)
        ... 11 more

It is similar as HBASE-4946, but I do not know how to solve this bug.
If add these custom class to the RegionServer's classloader may fix it, but it is conflicted with HBASE-6308 to prevent dependency conflicts.
Does anyone have some idea?