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  1. #1
    Join Date
    Jan 2004
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    Question Unanswered: Exporting in parallel using data pump

    Greetings,
    I apologize if this is a dumb question but I am a developer trying to tune our expdp script while our DBA is on leave. We specify multiple dmp files using dumpfile=filename%U_${filedate}.dmp and setting a max filesize of 25 gb. This creates 24 output files however it creates them one at a time, and I am trying to get the export to run in parallel to multiple dmp files. This is our expdp portion of the script

    expdp xxx/xxxxx@xxxxx dumpfile=filename%U_${filedate}.dmp \
    filesize=25g logfile=filename_${filedate}.log \
    tables=schema.tablename directory=dpdump\

    If I understand I can use PARALLEL=Int to run the export in parallel, is this true and what do I need to account for to tune it. My biggest concern is we run oracle10g and I ran across some documentation that PARALLEL can only be used in oracle11g. Is this true, and if so is there an alternative to 10g exports? Thanks for any help that can be provided.

  2. #2
    Join Date
    Aug 2003
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    Where the Surf Meets the Turf @Del Mar, CA
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    Provided Answers: 1
    How many concurrent parallel disk writers does it take to swamp the I/O capacity of DIRECTORY collecting the dump files?
    Last edited by anacedent; 07-12-11 at 00:31.
    You can lead some folks to knowledge, but you can not make them think.
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  3. #3
    Join Date
    Jan 2004
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    28
    I'm not really sure exactly what you're asking but we're not going to come close to swamping the I/O of the directory. We've got a P770 AIX box with 90 virtual cpus configured. Of the 24 output dmp files which currently run consecutively I'd like to set it up to run 4 or 8 files concurrently, which shouldn't tax out I/O capacity.

  4. #4
    Join Date
    Aug 2003
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    Provided Answers: 1
    Hard disk is at least 1,000 times SLOWER than CPU.
    I suspect that as few as 3 or 4 processes will 100% saturate single disk holding target DIRECTORY
    You can lead some folks to knowledge, but you can not make them think.
    The average person thinks he's above average!
    For most folks, they don't know, what they don't know.
    Good judgement comes from experience. Experience comes from bad judgement.

  5. #5
    Join Date
    Jan 2004
    Posts
    28
    We use a RAID disk array at RAID level 5 so data is distributed over multiple disks. I was under the impression that using parallel it would be able to create dmp files simultaneously on separate disks. And if parallel isn't available on 10G what would be the alternative?

  6. #6
    Join Date
    Jan 2004
    Location
    Croatia, Europe
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    Provided Answers: 4
    Perhaps you could put EXPDP statements into batch files (either one EXPDP per batch file, or several EXPDPs per batch file) and then schedule these batch files using your operating system's scheduler.

    For example: if there are 25 DMPs created, you could put 5 EXPDPs into a single batch file (which makes 5 batch files); then schedule these batch files - all 5 of them would start simultaneously. Export files are most probably not the same, so not all of them would finish at the same time, but some sort of "parallelism" might be accomplished.

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