Oracle 9.2 - using IMP with come the USERS.dbf datafile grew to 7GB and there is no data in any tables?

Posted on 2007-08-09
Last Modified: 2013-12-19
I recevied an export DMP file that was created with rows=n. I am importing that DMP file via IMP and my USERS datafile starts at .5 GB and after the IMP is done with ROWS=N (no data), the datafile grew to 7GB.

When you look at the stats, it shows Rows for most tables as >0, indicating there are rows in the tables, but when you do SELECT COUNT(1) there are none.  A COMPUTE STATISTICS then calcs all those Rows as 0, proving there is no data in the tables, but yet the datafile still sits at 7GB.  Why does it grow during IMP when there is no data being imported?
Question by:nshilling
    LVL 14

    Accepted Solution

    It's probably because of the storage definition of the tables. When you create a table in Oracle without any data, it will automatically allocate space for the initial extent.. SO if you had 100's of tables imported  each with a initial extent of 50M, then your data file would have grown to 5GB ..
    LVL 76

    Expert Comment

    by:slightwv (䄆 Netminder)
    sathyagiri is correct and should get the points.

    Just wanted to add:
    When you export you have the option 'compress extents'.  If you selected 'Y' then Oracle looks at the total table size and makes the 'initial' extent that size for import.  This guarantees the table will be contiguous on import.

    So, it doesn't have to be 100's of tables in the export.  It could be just 1 big table.

    Add 'show=y' to the import and look at the output.  you'll see the 'create table' statements but it won't do anything.

    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    PRTG Network Monitor: Intuitive Network Monitoring

    Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

    Suggested Solutions

    Working with Network Access Control Lists in Oracle 11g (part 1) Part 2: So, you upgraded to a shiny new 11g database and all of a sudden every program that used UTL_MAIL, UTL_SMTP, UTL_TCP, UTL_HTTP or any oth…
    Checking the Alert Log in AWS RDS Oracle can be a pain through their user interface.  I made a script to download the Alert Log, look for errors, and email me the trace files.  In this article I'll describe what I did and share my script.
    This video shows how to Export data from an Oracle database using the Original Export Utility.  The corresponding Import utility, which works the same way is referenced, but not demonstrated.
    This video shows how to configure and send email from and Oracle database using both UTL_SMTP and UTL_MAIL, as well as comparing UTL_SMTP to a manual SMTP conversation with a mail server.

    759 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    12 Experts available now in Live!

    Get 1:1 Help Now