RBS with transaction

[kevlar]

can anyone explain to me Y?

Terminal 1: sys user

SQL> show parameter transaction

NAME TYPE VALUE
------------------------------------ ------- ----------
distributed_transactions integer 16
transaction_auditing boolean TRUE
transactions integer 66
transactions_per_rollback_segment integer 1

1* select status,segment_name from dba_rollback_segs
SQL> /

STATUS SEGMENT_NAME
---------------- ------------------------------
ONLINE SYSTEM
ONLINE RBS01
OFFLINE RBS03
OFFLINE RBS04

Terminal 2 :


SQL> set transaction use rollback segment rbs01;

Transaction set.


1* insert into test values ('100',sysdate)
SQL> /

1 row created.

SQL> /

1 row created.

SQL> /

1 row created.


terminal 3:


SQL> insert into test values ('200',sysdate+2);

1 row created.

SQL> /

1 row created.

SQL> /

1 row created.


then i issued this command from terminal 1:

SQL> select status,segment_name from dba_rollback_segs;

STATUS SEGMENT_NAME
---------------- ------------------------------
ONLINE SYSTEM
ONLINE RBS01
OFFLINE RBS03
OFFLINE RBS04

SQL> alter rollback segment rbs01 offline;

Rollback segment altered.

SQL> select status,segment_name from dba_rollback_segs;

STATUS SEGMENT_NAME
---------------- ------------------------------
ONLINE SYSTEM
ONLINE RBS01
OFFLINE RBS03
OFFLINE RBS04


My question is :

1. why can I hold 2 transactions in one rollback segment when the transaction parameter is set to 1?

2. Why the "alter rollback segment rbs01 offline;" does not prompt any message that the rbs is containing a transaction instead it replied as if the rbs is taken offline but when you query dba_rollback segs the rbs is still online?

3. How can I simulate a deffered rollback segment?


Thank you very much for all your support.

[anandkl]

the parameter
transaction_per_rollback_segment specifies the no. of concurrent transaction each rollback can handle.Which means to say a rollback segment can handle one transaction at a time.
In ur case its handling one trancation at a time.

Cheese
anandkl

[Edited by anandkl on 01-23-2002 at 06:18 AM]