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From Anoop Sam John <anoo...@huawei.com>
Subject RE: Problems Loading RegionObserver Coprocessor
Date Sat, 26 May 2012 06:16:37 GMT
Hi Kevin



Instead of configuring the FQCN of your region observer against "hbase.coprocessor.region.classes",
you can go with configuring the same against the config param "hbase.coprocessor.user.region.classes"


This observer will not got called while dealing with ROOT and META table then...

From: Kevin [kevin.macksamie@gmail.com]
Sent: Friday, May 25, 2012 7:25 PM
To: user@hbase.apache.org
Subject: Problems Loading RegionObserver Coprocessor


I'm starting to give coprocessors a try, but I'm having trouble getting the
HBase cluster to start up properly after deploying the new configuration.
My coprocessor is trivial, but it is only to get my feet wet. I override
the prePut method to add the row being put into a table into another table
as well.

public class MyCustomRegionObserver extends BaseRegionObserver {

    public void prePut(final ObserverContext<RegionCoprocessorEnvironment>
            final Put put, final WALEdit edit, boolean writeToWAL)
            throws IOException {
        HTableInterface hti =
        try {
            hti.put(new Put(put.getRow()).add(Bytes.toBytes("num"),
                    Bytes.toBytes("value"), Bytes.toBytes(0)));
        } finally {


I updated hbase-site.xml to reflect this coprocessor.



I update all the machines with the new configuration and I added the
coprocessor jar to /usr/lib/hbase/lib on each machine (I don't change the
default HBase classpath in hbase-env.sh)

When I restart my HBase cluster the cluster does not ever finish assigning
META region. In the master's log there are a lot of
NotServingRegionExceptions: Region is not online: .META.,,1. Other than
that I can't see any log messages that indicate any specific about loading
the coprocessor. If I then comment out the coprocessor property in
hbase-site.xml and restart the cluster, then HBase starts up fine.

I am new to coprocessors so any help is great.


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