[ https://issues.apache.org/jira/browse/HBASE-4946?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zhihong Yu updated HBASE-4946: ------------------------------ Attachment: 4946-v4.txt Patch v4 removes eager instantiation. > HTable.coprocessorExec (and possibly coprocessorProxy) does not work with > dynamically loaded coprocessors (from hdfs or local system), because the RPC > system tries to deserialize an unknown class. > ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- > > Key: HBASE-4946 > URL: https://issues.apache.org/jira/browse/HBASE-4946 > Project: HBase > Issue Type: Bug > Components: coprocessors > Affects Versions: 0.92.0 > Reporter: Andrei Dragomir > Assignee: Andrei Dragomir > Attachments: 4946-v4.txt, HBASE-4946-v2.patch, HBASE-4946-v3.patch, > HBASE-4946.patch > > > Loading coprocessors jars from hdfs works fine. I load it from the shell, > after setting the attribute, and it gets loaded: > {noformat} > INFO org.apache.hadoop.hbase.regionserver.HRegion: Setting up tabledescriptor > config now ... > INFO org.apache.hadoop.hbase.coprocessor.CoprocessorHost: Class > com.MyCoprocessorClass needs to be loaded from a file - > hdfs://localhost:9000/coproc/rt- >0.0.1-SNAPSHOT.jar. > INFO org.apache.hadoop.hbase.coprocessor.CoprocessorHost: loadInstance: > com.MyCoprocessorClass > INFO org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost: > RegionEnvironment createEnvironment > DEBUG org.apache.hadoop.hbase.regionserver.HRegion: Registered protocol > handler: region=t1,,1322572939753.6409aee1726d31f5e5671a59fe6e384f. > protocol=com.MyCoprocessorClassProtocol > INFO org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost: Load > coprocessor com.MyCoprocessorClass from HTD of t1 successfully. > {noformat} > The problem is that this coprocessors simply extends BaseEndpointCoprocessor, > with a dynamic method. When calling this method from the client with > HTable.coprocessorExec, I get errors on the HRegionServer, because the call > cannot be deserialized from writables. > The problem is that Exec tries to do an "early" resolve of the coprocessor > class. The coprocessor class is loaded, but it is in the context of the > HRegionServer / HRegion. So, the call fails: > {noformat} > 2011-12-02 00:34:17,348 ERROR org.apache.hadoop.hbase.io.HbaseObjectWritable: > Error in readFields > java.io.IOException: Protocol class com.MyCoprocessorClassProtocol not found > at org.apache.hadoop.hbase.client.coprocessor.Exec.readFields(Exec.java:125) > at > org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:575) > at org.apache.hadoop.hbase.ipc.Invocation.readFields(Invocation.java:105) > at > org.apache.hadoop.hbase.ipc.HBaseServer$Connection.processData(HBaseServer.java:1237) > at > org.apache.hadoop.hbase.ipc.HBaseServer$Connection.readAndProcess(HBaseServer.java:1167) > at > org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:703) > at > org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.doRunLoop(HBaseServer.java:495) > at > org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:470) > at > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) > at java.lang.Thread.run(Thread.java:680) > Caused by: java.lang.ClassNotFoundException: com.MyCoprocessorClassProtocol > 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.client.coprocessor.Exec.readFields(Exec.java:122) > ... 10 more > {noformat} > Probably the correct way to fix this is to make Exec really smart, so that it > knows all the class definitions loaded in CoprocessorHost(s). > I created a small patch that simply doesn't resolve the class definition in > the Exec, instead passing it as string down to the HRegion layer. This layer > knows all the definitions, and simply loads it by name. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira