rollback segment query
DBAsupport.com Forums - Powered by vBulletin
Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: rollback segment query

  1. #1
    Join Date
    May 2002
    Location
    USA
    Posts
    462

    Wink

    Hi ,

    why does Public Rollback segment does not need an entry in init parameters & could u pls tell me the difference between public rollbacksegment and non public rollback segment .

    Thanks in advance

  2. #2
    Join Date
    Jul 2002
    Location
    Lincolnshire, IL
    Posts
    203
    A publick rollback segment is available to all Database instances and is brought online when the database is started.( For more then one instances)
    Whereas, a private rollback segment is available only to the instance that brings the rollback segment online.( For one instance only)
    So a public rollback segment is a kind of public property that's why we need not to make an entry in init parameter of a single database's init.ora file.
    Hope it helps
    Sandy
    "Greatest Rewards come only with Greatest Commitments!"

  3. #3
    Join Date
    May 2002
    Location
    USA
    Posts
    462
    Hi ,

    I have 6 public rollback segments present but i don't have transactions and transactions_per_rollback_segment parameters set in my production database . still the database is working fine .

    and we are not aware of the values for above parameters . presently we are we are doing some periodic batch loading .

    could anybody tell me if this becomes an issue at any point of time .

    pls help

  4. #4
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    There is no need of public rollback segments because the instance that gets first the PRBS keeps it untill shutdown. Accordingly, your instances might end up with improperly balanced RBSs.
    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g
    email: ocp_9i@yahoo.com

  5. #5
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    if you are using PUBLIC RBS then forget those parameter!

    plus they have default values

  6. #6
    Join Date
    Jul 2002
    Location
    Lincolnshire, IL
    Posts
    203
    You both are correct, 'EXPERTS' :-)
    Sandy
    "Greatest Rewards come only with Greatest Commitments!"

  7. #7
    Join Date
    May 2002
    Location
    USA
    Posts
    462
    Hi ,

    I could imagine value for transactions_per_rollback_segment but what could be the value for transaction prameter at any point of time . ( i believe a transaction is said to be completed, when commit is issued ) does this mean that number of transactions = number of process / sessions connected to the instance ?

    hope i am not deviating from main question

  8. #8
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Originally posted by prakashs43
    Hi ,

    I could imagine value for transactions_per_rollback_segment but what could be the value for transaction prameter at any point of time .
    One way to figure that out (in a big database) is to shedule a job run every 5' minute within say 24 hours. The job would execute a function which returns count(*) from v$transaction; and inserts the value amount in some temp table, call it T1. Then you can select avg(amount) from T1; This would give you the approximate/avg amount of transactions at a given point of time. You don't have to run the function every 5' in 24 hours. You may as well run it every minute within 2 hours or so.
    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g
    email: ocp_9i@yahoo.com

  9. #9
    Join Date
    Dec 2000
    Location
    Ljubljana, Slovenia
    Posts
    4,439
    If you are using Oracle9i you can easily find the maximum number of concurrent transaction at any time in the last 7 days with the following query:

    SELECT MAX(concurrency) FROM v$undostat;
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

  10. #10
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    may be select max(MAXCONCURRENCY) from v$undostat

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