Appendix C. FAQ

C.1. General
Are there other HBase FAQs?
Why are logs flooded with '2011-01-10 12:40:48,407 INFO org.apache.hadoop.io.compress.CodecPool: Got brand-new compressor' messages?
C.2. EC2
Why doesn't my remote java connection into my ec2 cluster work?
C.3. Building HBase
When I build, why do I always get Unable to find resource 'VM_global_library.vm'?
C.4. Runtime
Loading, why do I see pauses when loading HBase?
Why does my RegionServer hang inexplicitly?
C.5. How do I...?
Secondary Indexes in HBase?

C.1. General

Are there other HBase FAQs?
Why are logs flooded with '2011-01-10 12:40:48,407 INFO org.apache.hadoop.io.compress.CodecPool: Got brand-new compressor' messages?

Are there other HBase FAQs?

See the FAQ that is up on the wiki, HBase Wiki FAQ as well as the Troubleshooting page and the Frequently Seen Errors page.

Why are logs flooded with '2011-01-10 12:40:48,407 INFO org.apache.hadoop.io.compress.CodecPool: Got brand-new compressor' messages?

Because we are not using the native versions of compression libraries. See HBASE-1900 Put back native support when hadoop 0.21 is released. Copy the native libs from hadoop under hbase lib dir or symlink them into place and the message should go away.

C.2. EC2

Why doesn't my remote java connection into my ec2 cluster work?

Why doesn't my remote java connection into my ec2 cluster work?

See Andrew's answer here, up on the user list: Remote Java client connection into EC2 instance.

C.3. Building HBase

When I build, why do I always get Unable to find resource 'VM_global_library.vm'?

When I build, why do I always get Unable to find resource 'VM_global_library.vm'?

Ignore it. Its not an error. It is officially ugly though.

C.4. Runtime

Loading, why do I see pauses when loading HBase?
Why does my RegionServer hang inexplicitly?

Loading, why do I see pauses when loading HBase?

If compression is enabled, see this thread up on the user list, Long client pauses with compression.

Why does my RegionServer hang inexplicitly?

Are you running an old JVM (< 1.6.0_u21?)? When you look at a thread dump, does it look like threads are BLOCKED but no one holds the lock all are blocked on? See HBASE 3622 Deadlock in HBaseServer (JVM bug?). Adding -XX:+UseMembar to the HBase HBASE_OPTS in conf/hbase-env.sh may fix it.

C.5. How do I...?

Secondary Indexes in HBase?

Secondary Indexes in HBase?

For a useful introduction to the issues involved maintaining a secondary Index in a store like HBase, see the David Butler message in this thread, HBase, mail # user - Stargate+hbase