Intial extent calcuation size - urgent
DBAsupport.com Forums - Powered by vBulletin
Results 1 to 5 of 5

Thread: Intial extent calcuation size - urgent

  1. #1
    Join Date
    Sep 2000
    Posts
    77
    I have table with 5 columns each column length varchar2(4000). This table will have approx 150000 rows every year. I am planning for creating a seperate tablespace for this table because of its row size .
    While calculating rowsize i did it as below

    5* 4000 + 15( Column overhead of 3 bytes because col length is more than 250 bytes) + 3 (Row overhead) . 20018 bytes per row

    20018 * 150000 = Approx 2.8 Gig.
    I have enough space. Is it a good idea to have a intial extent of 2.8 gig size ? Please advise
    Thanks

  2. #2
    Join Date
    Apr 2000
    Location
    Edison, NJ
    Posts
    759
    Sure, you can create a table with that large of an initial extent.

  3. #3
    Join Date
    Sep 2000
    Posts
    77
    Can i use clob's instead ? JDBC will be retreving values from this table. I never tried CLOB's.
    Thanks

  4. #4
    Join Date
    Sep 2000
    Posts
    77
    Will i get lot of chained rows because of size of my row ? I think i will get that problem. If so what should i do?
    Thanks

  5. #5
    Join Date
    Nov 1999
    Location
    Elbert, Colorado, USA
    Posts
    81
    You could go ahead and create that large of an extent, but it tends to be a little unwieldy. You might want to go ahead with a smaller extent size or even consider partitioning your table - depending on what you expect to be doing with it.

    You may or may not get chained rows. If you have a sufficiently large db_block_size (e.g., 22K), you won't have chaining. However, if you are using a smaller block size, you definitely WILL have chaining and there's nothing you can do about that.

    However, if you use out-of-line CLOBs, then you will just have pointers in the table so row chaining should not occur. However, CLOBS will force you into more complex methods of loading/handling your data.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  



Click Here to Expand Forum to Full Width