问题:
1.在读取配置文件时，无法找到mapreduce.outputformat.class 的对应值
12/12/12 17:30:11 ERROR loader.OraLoader: mapreduce.outputformat.class is invalid
oracle.hadoop.loader.OraLoaderException: missing or invalid property "mapreduce.outputformat.class" value
解决：在执行hadoop ${OLH_JAR} oracle.hadoop.loader.OraLoader -conf /home/oracle/OLH/MyConf.xml 时，将MyConf.xml文件的路径写成了 HDFS文件系统的路径，将其改为LINUX 下的路径。
2.在进行连接时，无法连接监听器
解决: 没有配置好，本机的lisener,tnsname ,sqlnet 文件
3.在进行Loader时需要的文件， IN_DIRECTORY,OUT_DIRECTORY, DATAFILE,
重要的对象:
HDFS:
start:
mapred.input.dir,
mapreduce.outputformat.class
mapreduce.inputformat.class
mapreduce.output.dir
end:
oracle.hadoop.loader.loaderMapFile
oracle.hadoop.loader.targetTable
oracle.hadoop.loader.input.fieldNames
oracle.hadoop.loader.connection.url
<value>SCOTT.OLH_TABLE</value>
<name>oracle.hadoop.loader.input.fieldNames</name>
<value>col1,col2,col3,col4</value>
http://docs.oracle.com/cd/E27101_01/doc.10/e27365/olh.htm
[oracle@hadoop admin]$ hadoop dfs -rmr /user/root/olh_lab_out
Deleted hdfs://hdnode1m:9000/user/root/olh_lab_out
[oracle@hadoop admin]$ hadoop jar $OLH_HOME/jlib/oraloader.jar oracle.hadoop.loader.OraLoader -conf /home/oracle/OLH/MyConf.xml
Oracle Loader for Hadoop Release 2.0.0 - Production
Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
13/03/07 19:38:38 INFO loader.OraLoader: Oracle Loader for Hadoop Release 2.0.0 - Production
Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
13/03/07 19:38:38 INFO loader.OraLoader: Built-Against: hadoop-0.20.2 hive-0.7.1-cdh3u3 avro-1.6.3 jackson-1.8.8
13/03/07 19:38:39 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId=
13/03/07 19:38:40 INFO loader.OraLoader: oracle.hadoop.loader.loadByPartition is disabled because table: OLH_TABLE is not partitioned
13/03/07 19:38:40 INFO loader.OraLoader: oracle.hadoop.loader.enableSorting disabled, no sorting key provided
13/03/07 19:38:40 INFO output.DBOutputFormat: Setting reduce tasks speculative execution to false for : oracle.hadoop.loader.lib.output.JDBCOutputFormat
13/03/07 19:38:40 INFO jvm.JvmMetrics: Cannot initialize JVM Metrics with processName=JobTracker, sessionId= - already initialized
13/03/07 19:38:40 WARN loader.OraLoader: Sampler error: the number of reduce tasks must be greater than one; the configured value is 1 . Job will continue without sampled information.
13/03/07 19:38:40 INFO loader.OraLoader: Sampling time=0D:0h:0m:0s:13ms (13 ms)
13/03/07 19:38:40 INFO loader.OraLoader: Submitting OraLoader job OraLoader
13/03/07 19:38:42 INFO input.FileInputFormat: Total input paths to process : 1
13/03/07 19:38:42 INFO input.FileInputFormat: Total input paths to process : 1
13/03/07 19:38:42 INFO mapred.MapTask: io.sort.mb = 100
13/03/07 19:38:43 INFO mapred.MapTask: data buffer = 79691776/99614720
13/03/07 19:38:43 INFO mapred.MapTask: record buffer = 262144/327680
13/03/07 19:38:43 INFO mapred.MapTask: Starting flush of map output
13/03/07 19:38:43 INFO mapred.MapTask: Finished spill 0
13/03/07 19:38:43 INFO mapred.TaskRunner: Task:attempt_local_0001_m_000000_0 is done. And is in the process of commiting
13/03/07 19:38:43 INFO mapred.LocalJobRunner:
13/03/07 19:38:43 INFO mapred.TaskRunner: Task 'attempt_local_0001_m_000000_0' done.
13/03/07 19:38:43 INFO mapred.LocalJobRunner:
13/03/07 19:38:43 INFO mapred.Merger: Merging 1 sorted segments
13/03/07 19:38:43 INFO mapred.Merger: Down to the last merge-pass, with 1 segments left of total size: 1196 bytes
13/03/07 19:38:43 INFO mapred.LocalJobRunner:
13/03/07 19:38:43 INFO output.DBOutputFormat: conf prop: defaultExecuteBatch: 100
13/03/07 19:38:43 INFO output.DBOutputFormat: conf prop: loadByPartition: false
13/03/07 19:38:43 INFO output.DBOutputFormat: Insert statement: INSERT INTO "SCOTT"."OLH_TABLE" ("COL1", "COL2", "COL3", "COL4") VALUES (?, ?, ?, ?)
13/03/07 19:38:43 INFO mapred.TaskRunner: Task:attempt_local_0001_r_000000_0 is done. And is in the process of commiting
13/03/07 19:38:43 INFO mapred.LocalJobRunner:
13/03/07 19:38:43 INFO mapred.TaskRunner: Task attempt_local_0001_r_000000_0 is allowed to commit now
13/03/07 19:38:43 INFO output.JDBCOutputFormat: Committed work for task attempt attempt_local_0001_r_000000_0
13/03/07 19:38:43 INFO output.FileOutputCommitter: Saved output of task 'attempt_local_0001_r_000000_0' to /user/root/olh_lab_out
13/03/07 19:38:43 INFO mapred.LocalJobRunner: reduce > reduce
13/03/07 19:38:43 INFO mapred.TaskRunner: Task 'attempt_local_0001_r_000000_0' done.
13/03/07 19:38:43 INFO loader.OraLoader: map 100% reduce 100%
13/03/07 19:38:43 INFO loader.OraLoader: Job complete: OraLoader (null)
13/03/07 19:38:43 INFO loader.OraLoader: Counters: 14
FileSystemCounters
FILE_BYTES_READ=18885058
FILE_BYTES_WRITTEN=55486
HDFS_BYTES_READ=82429
HDFS_BYTES_WRITTEN=18957078
Map-Reduce Framework
Combine input records=0
Combine output records=0
Map input records=20
Map output bytes=1154
Map output records=20
Reduce input groups=1
Reduce input records=20
Reduce output records=20
Reduce shuffle bytes=0
Spilled Records=40