: Paul Baumgartel [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, February 26, 2002 6:54 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Users reading from rollback segments
Jeremiah is correct. In addition, rollback segments are read as part
of the delayed block cleanout process
of list ORACLE-L
Subject: RE: Users reading from rollback segments
Jeremiah is correct. In addition, rollback segments are read as part
of the delayed block cleanout process, and it's not possible
to predict
that, either.
--- Jeremiah Wilton [EMAIL PROTECTED] wrote:
People also
The delayed_logging_block_cleanouts parameter does not force or
suppress cleanouts. It just makes any cleanouts that do occur get
logged as redo entries.
--
Jeremiah Wilton
http://www.speakeasy.net/~jwilton
On Wed, 27 Feb 2002, Diego Cutrone wrote:
Hi Glenn and list:
As you mentioned,
Jeremiah :
What I meant was that the delayed_logging_block_cleanouts parameter
(=FALSE) will make the next reader of the block to cleanout that block.
Now, if this parameter's value is TRUE (default in Oracle 7 and 8.0) the
next reader will NOT clean out the block (it will read the
Here is the Query you are looking for.
set lines 132
set pages 30
col rr heading 'RB Segment' format a18
col os heading 'OS User' format a10
col te heading 'Terminal' format a10
col sid format 9
col spid format 99
select r.name ROLLBACK SEG, s.sid, s.serial#,
Why would you want to shrink a rollback segment?
-Original Message-
From: Glenn Travis [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, February 26, 2002 2:38 PM
To: Multiple recipients of list ORACLE-L
Subject: Users reading from rollback segments
Is there a way to tell if anyone is
To partially answer your question, xacts in v$rollstat will tell you if
there are any active transactions in the rollback segment.
Raj
Glenn Travis
Is there a way to check if the rollback segment is in use first?
I use following script to see which rollbacks are in use...and then shrink
to certain size if it requires to do that...
select substr(a.os_user_name,1,8) OS User
,substr(e.username,1,8) DB User
, substr(b.object_name,1,30)
SELECT segment_name,
USN,EXTENTS,RSSIZE,HWMSIZE,optsize,xacts,aveactive,WRAPS,shrinks FROM
V$ROLLSTAT,
dba_rollback_segs
where usn=segment_id
xacts =1 is in use. otherwise it is 0.
oracle 8.1.6 you can take an active rollback segment offline, but also
kill the transaction. 8.17 supposed to fix
Thanks for the replies. I have all sorts of neat queries (which I can post) which
show me gobs of information about my rollback segments (sizes, extents, optimal,
shrinks, active transactions, block used by those transcations, ad infinitum...).
HOWEVER, I still cannot find an answer to my
: Tuesday, February 26, 2002 3:51 PM
To: Multiple recipients of list ORACLE-L
Subject: Re: Users reading from rollback segments
SELECT segment_name,
USN,EXTENTS,RSSIZE,HWMSIZE,optsize,xacts,aveactive,WRAPS,shrinks FROM
V$ROLLSTAT,
dba_rollback_segs
where usn=segment_id
xacts =1 is in use
Since you cannot predict who might need to generate consistent reads
from the RBS in the FUTURE, you cannot predict if you will cause
ORA-01555 or not by shrinking.
Your best bet is to get rid of people bloating up RBSs by limiting
their growth, and enforcing the use of smaller transactions.
People also obtain read consistency data from the rollback segments
after transactions have committed. If a query began before someone
else's transaction committed, but continues reading, then needs the
reconstruct the data from before the commit, in needs rollback data
that is both committed
of my
employer or clients **
-Original Message-
From: Jeremiah Wilton [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, February 26, 2002 2:36 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Users reading from rollback segments
People also obtain read consistency data from
]cc:
Sent by: Subject: RE: Users reading from rollback
segments
[EMAIL PROTECTED
Jeremiah is correct. In addition, rollback segments are read as part
of the delayed block cleanout process, and it's not possible to predict
that, either.
--- Jeremiah Wilton [EMAIL PROTECTED] wrote:
People also obtain read consistency data from the rollback segments
after transactions have
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