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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Trivial Update of "Hbase/FAQ" by stack
Date Wed, 07 Jan 2009 22:54:57 GMT
Dear Wiki user,

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The following page has been changed by stack:
http://wiki.apache.org/hadoop/Hbase/FAQ

The comment on the change is:
Notes on OOME

------------------------------------------------------------------------------
  
  '''4. [[Anchor(4)]] Can I fix OutOfMemoryExceptions in hbase?'''
  
- Out-of-the-box, hbase uses the default JVM heap size.  Set the ''HBASE_HEAPSIZE'' environment
variable in ''${HBASE_HOME}/conf/hbase-env.sh'' if your install needs to run with a larger
heap.  ''HBASE_HEAPSIZE'' is like ''HADOOP_HEAPSIZE'' in that its value is the desired heap
size in MB.  The surrounding '-Xmx' and 'm' needed to make up the maximum heap size java option
are added by the hbase start script (See how ''HBASE_HEAPSIZE'' is used in the ''${HBASE_HOME}/bin/hbase''
script for clarification).
+ Out-of-the-box, hbase uses a default of 1G heap size.  Set the ''HBASE_HEAPSIZE'' environment
variable in ''${HBASE_HOME}/conf/hbase-env.sh'' if your install needs to run with a larger
heap.  ''HBASE_HEAPSIZE'' is like ''HADOOP_HEAPSIZE'' in that its value is the desired heap
size in MB.  The surrounding '-Xmx' and 'm' needed to make up the maximum heap size java option
are added by the hbase start script (See how ''HBASE_HEAPSIZE'' is used in the ''${HBASE_HOME}/bin/hbase''
script for clarification).
+ 
+ Otherwise, particularly if small cells, upping the default '''hbase.io.index.interval'''
configuration (or setting '''io.map.index.skip''') -- see the '''hbase-default.xml''' for
descriptions -- has the greatest effect on amount of heap used.  You can also try downing
'''hbase.regionserver.globalMemcache.upperLimit''' and '''hbase.regionserver.globalMemcache.lowerLimit'''.
  
  '''5. [[Anchor(5)]] How do I enable hbase DEBUG-level logging?'''
  

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