本文整理汇总了Java中org.apache.hadoop.mapred.JobConf.getNumReduceTasks方法的典型用法代码示例。如果您正苦于以下问题:Java JobConf.getNumReduceTasks方法的具体用法?Java JobConf.getNumReduceTasks怎么用?Java JobConf.getNumReduceTasks使用的例子?那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类org.apache.hadoop.mapred.JobConf
的用法示例。
在下文中一共展示了JobConf.getNumReduceTasks方法的3个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: initTableReduceJob
import org.apache.hadoop.mapred.JobConf; //导入方法依赖的package包/类
/**
* Use this before submitting a TableReduce job. It will
* appropriately set up the JobConf.
*
* @param table The output table.
* @param reducer The reducer class to use.
* @param job The current job configuration to adjust.
* @param partitioner Partitioner to use. Pass <code>null</code> to use
* default partitioner.
* @param addDependencyJars upload HBase jars and jars for any of the configured
* job classes via the distributed cache (tmpjars).
* @throws IOException When determining the region count fails.
*/
public static void initTableReduceJob(String table,
Class<? extends TableReduce> reducer, JobConf job, Class partitioner,
boolean addDependencyJars) throws IOException {
job.setOutputFormat(TableOutputFormat.class);
job.setReducerClass(reducer);
job.set(TableOutputFormat.OUTPUT_TABLE, table);
job.setOutputKeyClass(ImmutableBytesWritable.class);
job.setOutputValueClass(Put.class);
job.setStrings("io.serializations", job.get("io.serializations"),
MutationSerialization.class.getName(), ResultSerialization.class.getName());
if (partitioner == HRegionPartitioner.class) {
job.setPartitionerClass(HRegionPartitioner.class);
int regions =
MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job), TableName.valueOf(table));
if (job.getNumReduceTasks() > regions) {
job.setNumReduceTasks(regions);
}
} else if (partitioner != null) {
job.setPartitionerClass(partitioner);
}
if (addDependencyJars) {
addDependencyJars(job);
}
initCredentials(job);
}
示例2: checkSpecs
import org.apache.hadoop.mapred.JobConf; //导入方法依赖的package包/类
private void checkSpecs(Job job) throws ClassNotFoundException,
InterruptedException, IOException {
JobConf jConf = (JobConf)job.getConfiguration();
// Check the output specification
if (jConf.getNumReduceTasks() == 0 ?
jConf.getUseNewMapper() : jConf.getUseNewReducer()) {
org.apache.hadoop.mapreduce.OutputFormat<?, ?> output =
ReflectionUtils.newInstance(job.getOutputFormatClass(),
job.getConfiguration());
output.checkOutputSpecs(job);
} else {
jConf.getOutputFormat().checkOutputSpecs(jtFs, jConf);
}
}
示例3: limitNumReduceTasks
import org.apache.hadoop.mapred.JobConf; //导入方法依赖的package包/类
/**
* Ensures that the given number of reduce tasks for the given job
* configuration does not exceed the number of regions for the given table.
*
* @param table The table to get the region count for.
* @param job The current job configuration to adjust.
* @throws IOException When retrieving the table details fails.
*/
// Used by tests.
public static void limitNumReduceTasks(String table, JobConf job)
throws IOException {
int regions =
MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job), TableName.valueOf(table));
if (job.getNumReduceTasks() > regions)
job.setNumReduceTasks(regions);
}