HBase重要参数，其他的参数查看文件

设置hadoop的系统参数时可以使用-D ,这个要放在程序参数的前面


== 使用HBASE作为输入 ==

{{{
 public static class MapClass extends TableMapper...
}}}
可以使用TableInputFormate的参数

hbase.mapreduce.inputtable 
hbase.mapreduce.scan /** 输入字符串转换为Scan */
hbase.mapreduce.scan.row.start   /** Scan start row */
hbase.mapreduce.scan.row.stop  /** Scan stop row */
hbase.mapreduce.scan.column.family /** Column Family to Scan */
hbase.mapreduce.scan.columns  /** Space delimited list of columns to scan. */
hbase.mapreduce.scan.timestamp /** The timestamp used to filter columns with a specific timestamp. */
hbase.mapreduce.scan.timerange.start
hbase.mapreduce.scan.timerange.end
hbase.mapreduce.scan.maxversions
hbase.mapreduce.scan.cacheblocks  /** Set to false to disable server-side caching of blocks for this scan. */
hbase.mapreduce.scan.cachedrows  /** The number of rows for caching that will be passed to scanners. */


== 注意要点：[[BR]] ==


使用HBASE的时候建议关闭 冗余工作 [http://hbase.apache.org/book/mapreduce.specex.html Speculative Execution]

 mapred.map.tasks.speculative.execution=false
 mapred.reduce.tasks.speculative.execution= false