3 Replies Latest reply: May 27, 2012 9:12 PM by user1745344 RSS

    How to use Oracle Direct Connector for HDFS(DCH)?

    user1745344
      hi all,

      I am trying to use Oracle database to access HDFS through DCH. Now I installed Oracle database 11.2, hadoop-0.20.2 and DCH on the same linux machine.
      I also configured hdfs_stream properly and created Oracle directory HDFS_BIN_PATH according to README.txt file within DCH.
      Now I encountered a problem, how I create a external table which access data residing on HDFS?

      Can anyone help me ?
      Thanks in advance.

      Chopsun

      Edited by: user1745344 on 2012-5-21 下午11:30
        • 1. Re: How to use Oracle Direct Connector for HDFS(DCH)?
          user1745344
          I figure out the way which access HDFS data from Oracle External Table through DCH as below, but still face some problems

          Step 1
          Created Oracle directories as following:
          CREATE OR REPLACE DIRECTORY hdfs_bin_path AS '/home/oracle/orahdfs/bin';
          CREATE OR REPLACE DIRECTORY data_dir AS '/user/hadoop';
          where /user/hadoop is HDFS directory in which data file test.txt located.

          Step 2
          Created Oracle external table as following:
          create table xqs_ext_test(col1 varchar2(100))
          organization external (
          TYPE oracle_loader
          DEFAULT DIRECTORY data_dir
          ACCESS PARAMETERS (
          records delimited by newline
          preprocessor hdfs_bin_path:'hdfs_stream'
          badfile hdfs_bin_path:'empxt%a_%p.bad'
          logfile hdfs_bin_path:'empxt%a_%p.log'
          fields terminated by ','
          )
          LOCATION ('test.txt'))
          reject limit unlimited
          parallel 2;

          when run SQL statement : select * from xqs_ext_test; the following error was prompted:

          SELECT * FROM xqs_ext_test
          *
          ERROR at line 1:
          ORA-29913: error in executing ODCIEXTTABLEOPEN callout
          ORA-29400: data cartridge error
          KUP-04040: file test.txt in DATA_DIR not found


          who can help me out with this problem?


          Best Regards

          Chopsun

          Edited by: user1745344 on 2012-5-22 上午1:02
          • 2. Re: How to use Oracle Direct Connector for HDFS(DCH)?
            Jean-Pierre Dijcks-Oracle
            Ok, silly question, but does the file exist there? Also, just to check, do you have the db patches/code installed?

            JP
            • 3. Re: How to use Oracle Direct Connector for HDFS(DCH)?
              user1745344
              this problem got solved.

              thanks

              Chopsun.