Shrinking of rollback segments may result in ORA-1555s. If you need to shrink
them, do so during a slow time.
Not shrinking rollback segments may result in ORA-1562 unable to extend rbs.
Satav, Pawan wrote:
Hi,
Can anyone point pros/cons of shrinking a rollback segment ? (other
than
AK
Sometime when your system isn't at its peak, just take the segment
offline. Then wait a little while and check the status. Oracle won't take
the segment offline as long as active processes are using it. Oracle won't
let you drop it until it is able to take it offline.
Dennis Williams
You can take the rollback segment offline. It will not impact any currently
running transactions and no new transactions will be assigned to it. Oracle
will not let you drop a rollback segment while there are any active transactions
writing undo to the rollback segment. IIRC, the
ak,
Here is a query you can run to see if it is currently in use...
SQL select b.segment_name, a.xacts, a.shrinks, a.wraps, a.extends
2 from v$rollstat a, dba_rollback_segs b
3 where a.usn = b.segment_id
4 /
SEGMENT_NAMEXACTSSHRINKS WRAPSEXTENDS
Zhu Chao,
Please be aware that rollback segments serve two major purposes:
* recover individual transactions (i.e. rollback)
* provide before-image information for read-consistency
The information you are getting from V$ROLLSTAT and STATSPACK is accurate at
measuring the first purpose
3 options
1. if possible , put a commit in your procedure to reduce load on rollback
segs
2. ask your dba to increase size of rollback segments. Since rollback
segment allocation is random, u may have to drop the smaller rbs segs and
create new larger segs
3. increase the maxextents of existing
Use used_ublk, used_urec from v$transaction. You will need to join to
v$session to get the session info.
USED_UBLK USED_UREC
-- --
12918
-Original Message-
Sent: Wednesday, October 23, 2002 11:02 AM
To: Multiple recipients of list ORACLE-L
Hi all,
SELECT
r.NAME, -- rbs name
s.sid,
s.serial#,
s.username,
s.machine,
t.status,
t.cr_get, -- consistent gets
t.phy_io, -- physical IO
t.used_ublk, -- Undo blocks used
t.noundo, -- Is a noundo transaction
SUBSTR (s.program, 1, 78) COMMAND,
s.username DB User,
George,
Try this query and check for average_active
select ud.name,
sg.extents ext,
round(sg.blocks * ts.blocksize / 1048576, 2) MB,
round(s.optsize / 1048576, 1) optsize,
round(s.aveactive / 1048576, 1) AVEACT,
round(s.hwmsize / 1048576, 1) HWMSIZE,
Hi Kevin,
Fantastic, thx, just what I was looking for, will event tell the oracle
support person that could not even assist.
George
George Leonard
Oracle Database Administrator
Dimension Data (Pty) Ltd
(Reg. No. 1987/006597/07)
Tel: (+27 11) 575
before you do all this by fragmented do you mean that there are a
large number of free extents in the tablespace?
If so, are those extents all the same size or at least a multiple of
the same size?
If so, why are you bothering to defragment?
You would only need to defragment the rollback
Why do you think it is fragmented?
Why do you think it is a problem?
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Monday, October 07, 2002 10:36 AM
Hi
My rollback tablespace is highly fragmented.I am thinking to do like
following?
-Create
Terry,
Can you see if there are any session(s) (runaway or not) that might be
causing your rollback segments to fill up? Until you can figure out what
sessions are filling up the rollbacks you will be stuck adding more space
until those session(s) end.
Bryan
-Original Message-
Sent:
Terry,
What do you have optimal set to? I believe shrink only shrinks to the optimal size.
Jim
Ball, Terry [EMAIL PROTECTED] wrote:
Oracle 8.1.6.3 on Sun Solaris 2.6.
The rollback tablespace filled up last night and the rollback segments
became full. I added space to the tablespace and
The rollback segment will not shrink if there are active transactions in
the rollback segment i.e xacts 0 in v$rollstat for that rollback segment.
Check out which transaction is using the rollback segments using
v$transaction where XIDUSN = usn from v$rollname. The ses_addr in
v$transaction
Title: RE: Rollback segment shrinks
Terry,
This query will tell you which process is using which rollback segment, maybe
that'll help you backtrack to find out what's going on.
column Oracle UserName FORMAT a15
column RBS Name format a15
select r.name RBS Name, p.spid, l.sid ORACLE PID
Alternately run this querry to check which rollback segments are in use...
set linesize 120
select substr(a.os_user_name,1,8) OS User
, substr(b.object_name,1,30) Object Name
, substr(b.object_type,1,8) Type
, substr(c.segment_name,1,10) RBS
, e.process PROCESS
, substr(d.used_urec,1,8) # of
Title: RE: Rollback segment shrinks
Terry,
This query will tell you which process is using which rollback segment, maybe
that'll help you backtrack to find out what's going on.
column Oracle UserName FORMAT a15
column RBS Name format a15
select r.name RBS Name, p.spid, l.sid ORACLE PID
Hi all,=0D
=0D
How to find out the smallest (minimal) transaction
size from Dictionary vie=
w or base tables =0D
I try to set my OPTIMAL rollback segment base on
smallest transaction size =
to prevent ora-1555. since shrinking rollback
segments may cause ora-1555.=
=0D
=0D
=0D
Thanks =0D
=0D
Thanks man,
I mean the minimum optimal size base on the maximum transaction size, So the HWM is
the answer ?
Sinardy
-Original Message-
Sent: 03 June 2002 16:53
To: Multiple recipients of list ORACLE-L
Hi all,=0D
=0D
How to find out the smallest (minimal) transaction
size from
Hi Stephane,
I run the script and I have
OPTIMAL = 5 * ceil(max(v$rollstat.aveactive) / 4 / sys.ts$.blocksize)*
sys.ts$.blocksize / 1024
the result is 0 K for my optimal. : )
regards,
Sinardy
-Original Message-
Sent: 03 June 2002 16:53
To: Multiple recipients of list ORACLE-L
Thanks man,=0D
=0D
I mean the minimum optimal size base on the maximum
transaction size, So th=
e HWM is the answer ?=0D
=0D
=0D
Sinardy=0D
=0D
Depends. If activity was 'normal', yes (if HWM is about the same for all RS, you can
be fairly confident with the value). If somebody has run a big
Hi Stephane,=0D
=0D
I run the script and I have =0D
=0D
OPTIMAL =3D 5 * ceil(max(v$rollstat.aveactive) / 4
/ sys.ts$.blocksize)* sy=
s.ts$.blocksize / 1024 =0D
=0D
the result is 0 K for my optimal. : )=0D
=0D
regards,=0D
Sinardy=0D
Probably not enough significant activity. It tries to set
I find that not setting OPTIMAL seems to be optimal.
Jared
Sinardy Xing [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
06/02/2002 09:53 PM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
cc:
Subject:Rollback Segment
I figured you were, but I didn't want someone to mistakenly get the idea
that
it somehow made copying legal... :-). In fact, I'm not sure whats going to
happen at this point
RF
Robert G. Freeman - Oracle8i OCP
Oracle DBA Technical Lead
CSX Midtier Database Administration
The Cigarette
I'm just joking with you...
-Original Message-
Sent: Thursday, March 28, 2002 4:25 PM
To: Multiple recipients of list ORACLE-L
Does this mean we can freely copy these books now??
Of course not!! :-(
Robert G. Freeman - Oracle8i OCP
Oracle DBA Technical Lead
CSX Midtier Database
Don't specify OPTIMAL parameter for rollback segment.
Igor Neyman, OCP DBA
[EMAIL PROTECTED]
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Thursday, March 28, 2002 1:38 PM
Hi
I am looking lot of shrinkage in rollback segment.please suggest.
Ross Keep the rollback segments out of the cold water. Shrinkage is bad.
/Ross
Scott Shafer
San Antonio, TX
210-581-6217
Common sense will not accomplish great things. Simply become insane and
desperate.
-Original Message-
From: Seema Singh [SMTP:[EMAIL PROTECTED]]
Sent: Thursday,
Anyone here write books for Coriolis? They are closing up
shop effective today. No more Exam Crams, black books, etc...
RF
Robert G. Freeman - Oracle8i OCP
Oracle DBA Technical Lead
CSX Midtier Database Administration
The Cigarette Smoking Man: Anyone who can appease a man's conscience can
Alternately run following script and set your optimal nearest to HWMSIZE as
a start. It requires a lot of monitoring to set optimal according to your
application requirement.
select ud.name,
sg.extents ext,
round(sg.blocks * ts.blocksize / 1048576, 2) MB,
round(s.optsize /
Thanks for the FYI.
Do you have any details as to why they are closing up shop? I thought there
Exam Cram and Black books were popular
Does this mean we can freely copy these books now??
-Original Message-
Sent: Thursday, March 28, 2002 3:08 PM
To: Multiple recipients of list
Does this mean we can freely copy these books now??
Of course not!! :-(
Robert G. Freeman - Oracle8i OCP
Oracle DBA Technical Lead
CSX Midtier Database Administration
The Cigarette Smoking Man: Anyone who can appease a man's conscience can
take his freedom away from him.
-Original
-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
_
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com
--
Please see the official
-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
Behalf Of Mohammad
Rafiq
Sent: Wednesday, February 13, 2002 9:54 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re
PROTECTED]]On
Behalf Of Mohammad
Rafiq
Sent: Wednesday, February 13, 2002 9:54 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
PROTECTED] [mailto:[EMAIL PROTECTED]]On
Behalf Of Mohammad
Rafiq
Sent: Wednesday, February 13, 2002 9:54 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
_
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com
--
Please see
PROTECTED] [mailto:[EMAIL PROTECTED]]On
Behalf Of Mohammad
Rafiq
Sent: Wednesday, February 13, 2002 9:54 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
] [mailto:[EMAIL PROTECTED]]On
Behalf Of Mohammad
Rafiq
Sent: Wednesday, February 13, 2002 9:54 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
Behalf Of Mohammad
Rafiq
Sent: Wednesday, February 13, 2002 9:54 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
In many cases you will have to take RB segments offline
and drop them, then
re-create
Thanks a lot for ur help, Rafiq. I have acted as per ur recommendation
and asked the customer to try the delete job again.have not received
a feedback from them yet but sometimes they only revert back to me if they
have faced a problem again.if I do not hear anything by this evening,
I
Rafiq,
Just a small questionr the rollback segment extents in the rollback
segment tablespace de-allocated when the database is shut down ??
In that case, does the fragmentation remain when the database is restarted
or r the blocks coalesced automatically ??
Regards,
Samir
Samir Sarkar
Samir,
It is not coalesced automatically at shutdown and startup. It is to be
coalesced manually. It applies to any tablespace with pctincrease set as
0(zero). I have no idea of 9i but this is normal behaviour of ver 7.3.4 to
8.1.7...
Regards
Rafiq
Reply-To: [EMAIL PROTECTED]
To: Multiple
Samir,
Thanks..Due to lot of activities of rollback segment resulting in shrinkage
make rbs tablesapce fragmented hence contigous space becomes a
issue...Possible solution to set a good size of optsize of rbs to avoid
shrinkages or frequent coalesing of rbs tablespace / or any other tablespace
Thanks a lot, Rafiqthe output from ur query after running it on the
database
showed the rollback segment to be highly fragmented.the total extents
were
7490 and the extents coalesced were only 440. The initial and next extents
have been set at 409K which seems to me as quite small.
contiguous free space it try coalesce itself.
Alex Hillman
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Mohammad
Rafiq
Sent: Tuesday, February 12, 2002 4:53 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
Hi, guys,
Just my $0.02, coalescing free space will NEVER eliminate fragmentation. In
many cases you will have to take RB segments offline and drop them, then
re-create. In the interim period you might want to have a big rollback
segment(or a few) in another tablespace.
Best,
Sergey
In many cases you will have to take RB segments offline and drop them, then
re-create
--Even in this case you have to coalesce rbs tablespace before
recreating rollback segments using that particular tablespace to make all
released extents as contigous...Besides it is a good practice to
Samir,
For a long term solution, it is better to reorg rbs tablespace and rollback
segments with correct sizing based on usage...
You may use following script to get better info about rollback segments
usage
1 set linesize 120
2 column name format A15
3 column status format A7
4
contiguous free space it try coalesce itself.
Alex Hillman
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Mohammad
Rafiq
Sent: Tuesday, February 12, 2002 4:53 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
IN THIS CASE yes, but NOT BEFORE That was my point.
Thanks,
Best,
Sergey
-Original Message-
Sent: Wednesday, February 13, 2002 12:54 PM
To: Multiple recipients of list ORACLE-L
In many cases you will have to take RB segments offline and drop them, then
re-create
--Even in
Exactly. It depends pretty much on the application, how often it commits
transactions, segment sizes, of course, OLTP amount etc. You can't always
wait for SMON to wake up and do its job. The point is COALESCING alone won't
always help and you have to defrag. Another point is ONE thing is reading
Of Babich ,
Sergey
Sent: Wednesday, February 13, 2002 3:00 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Rollback Segment Problem
Exactly. It depends pretty much on the application, how often it commits
transactions, segment sizes, of course, OLTP amount etc. You can't always
wait
Here you are absolutely right...
Regards
Rafiq
Reply-To: [EMAIL PROTECTED]
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Date: Wed, 13 Feb 2002 11:59:53 -0800
Exactly. It depends pretty much on the application, how often it commits
transactions, segment sizes, of course, OLTP
You never need to recreate the rollback segments (DROP and CREATE) unless
the rollback segment dies. THe rollback segment will die after approx 4M
(the number is not very accurate.. okay,, some number)transactions.
THis is the only case I need to drop and recreate them.
Best Regards,
K
Is your tablespace fragmented as it is not finding contingous extent ..
TRy to coalesce your subject tablespace and try...
you can use following script to check whether coalesing is required or not..
If percent is 100 then coalesce it..
select substr(tablespace_name,1,10)TS_NAME,total_extents
Rafiq,
While your script provides a lot of good information, it sure is slow on my system. It
took 1:44 minutes while my script below took 420 mseconds. I was really surprised as
my script has a self-join. Then I checked out dba_free_space_coalesced. It sure is
complicated as it calls on two
Jerry,
Thanks for sharing script. We might have better systems as timing was never
be a issue. I just tested my script on 2 systems and it ran between 34.5
mseconds to 4.65 seconds...and on the basis of it is results we coalesce all
such tablespaces. I prefer to keep pctincrease of tablespaces
Hi Raj,
Interesting that you first agree with Jeremy and then argue with him. It
is precisely because
export does not generate rollback that the "gymnastics" of taking all of
the other rbs's offline
will not help anything. It might make you feel better, however :-).
John
[EMAIL PROTECTED]
John,
I DISAGREE. The gymnastics of assigning a large rollback segment to an
export could avoid the snapshot too old error.
I agree with Jeremy when he says export does not generate rollback. But I
was trying to impress upon him that still an export could end up with the
snapshot too old
HI Raj,
I hope you feel better :-).
John
[EMAIL PROTECTED] wrote:
John,
I DISAGREE. The gymnastics of assigning a large rollback segment to an
export could avoid the snapshot too old error.
I agree with Jeremy when he says export does not generate rollback. But I
was trying to impress upon
Guys, in the next round, please correct Mr. Wilton's first name to -
Jeremiah.
Cut paste is a wonderful thing ;-)
- Kirti
-Original Message-
Sent: Friday, January 25, 2002 10:35 AM
To: Multiple recipients of list ORACLE-L
John,
I DISAGREE. The gymnastics of assigning a large
Sorry Jeremiah!
John
[EMAIL PROTECTED] wrote:
Guys, in the next round, please correct Mr. Wilton's first name to -
Jeremiah.
Cut paste is a wonderful thing ;-)
- Kirti
-Original Message-
Sent: Friday, January 25, 2002 10:35 AM
To: Multiple recipients of list ORACLE-L
John,
Jeremiah, it is.
Thanks, Kirit ;-)
Raj
Deshpande, Kirti [EMAIL PROTECTED]@fatcity.com on 01/25/2002
12:55:27 PM
Please respond to [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
cc:
Guys, in the next round, please correct
Export doesn't generate any rollback, right, so what is it supposed to
accomplish by doing this incantation?
Sorry to press the point, but could you elaborate on how that COULD
possibly make any difference for 'snapshot too old'?
For the same reason, any other transaction could end up with
) to
read-only.
Yechiel Adar, Mehish Computer Services
[EMAIL PROTECTED]
-Original Message-
From: [EMAIL PROTECTED] [SMTP:[EMAIL PROTECTED]]
Sent: Wed, January 23, 2002 2:00 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: ROLLBACK SEGMENT?
H ... COULD help in avoiding
HI Seema,
Export is reading the data from the oracle database and writing it to an
associated binary file. It only uses rollback segments to provide read
consistency of data blocks being read. This will need to use whatever
rbs's have been assigned to the blocks we are reconstructing.
HI
There is no direct way in Oracle for Export to use a
particular rollback segment.
But you can use the following trick to assign export a
particular rollback segment -
1) Create a rollback segment tablespace with one large
segment and bring it online before export.
2) Offline all existing
The ORA-1555 is a read consistency error. The
information from the rollback segments needed to
create a read-consistent view of the data is not
available. Usually because the information has been
overwritten or the extents containing this information
have been deallocated (e.g. if optimal is
Another way of avoiding ora-1555 errors is issuing 'LOCK TABLE xxx
in EXCLUSIVE MODE' before issuing a select statement. That will make
sure that no transaction is modifying the table you're reading and
you will not get any ora-1555 errors. This is especially useful in
an OLTP environment.
Hey Anita, this is really a cool workaround .. who
thought these dummy transactions were so damn smart
!!! this implementation of dummy Xns i am hearing
about for the first time .. let me admit ;)
Great mail!!
Thx
Deepak
--- A. Bardeen [EMAIL PROTECTED] wrote:
The ORA-1555 is a read
ok so let me chirp in as well .. another way of
preventing 1555 is to first do a full table scan on
the table you are about to mess with .. to prevent
delayed block cleanout effect .. go figure ;)
Deepak
--- Gogala, Mladen [EMAIL PROTECTED] wrote:
Another way of avoiding ora-1555 errors is
I think you forgot to assign a transaction to the
increased RBS
Suppose the increased RBS is RBS2 then
SET TRANSACTION USE ROLLBACK SEGMENT RBS2;
After that do an export again .
I think it will work.
--- Jackson Dumas [EMAIL PROTECTED] wrote:
Yeah
I had a problem recently were I was
I think you forgot to assign a transaction to the
increased RBS
Suppose the increased RBS is RBS2 then
SET TRANSACTION USE ROLLBACK SEGMENT RBS2;
After that do an export again .
I think it will work.
--- Jackson Dumas [EMAIL PROTECTED] wrote:
Yeah
I had a problem recently were I was
Hi Mr Dumas ,
Why not using direct path load In export specify : Direct = y
Regards
-Original Message-
From: ASHRAF SALAYMEH [SMTP:[EMAIL PROTECTED]]
Sent: Saturday, November 17, 2001 1:30 PM
To: Multiple recipients of list ORACLE-L
Subject: Re: Rollback
For a consistent read, the export needs to the
rollback segments, but they are being recycled by
other txns in your db. So you'll need one or more of:
- larger rollback segs
- less activity whilst your doing your export
- faster exports
hth
connor
--- Jackson Dumas [EMAIL PROTECTED] wrote:
metalink documents 10630.1 69464.1 62005.1 and 45895.1 will help
The key is to hold on to committed values in the rollback segments as long
as possible. You can add rollback segments, increase their size (i.e.
increase MINEXTENTS), avoid using OPTIMAL (maybe a debateable suggestion)
but do not
Folks,
All of the underscore parameters used to force the db
open or ignore inconsistency in the redo logs or the
RBS's, such as the one below, have two major
drawbacks:
1. The db MUST be recreated afterwards (recreating
the RBS and/or RBS tablespace is not sufficient).
2. Most likely there
Kamel,
Just because an RBS can extend doesn't mean it will.
From the description you've given I suspect that the
transactions were committing fast enough that when it
came time to wrap around from one exent to the next,
the next extent didn't have any active transactions so
it was reused
Hello Kevin,
yes, if The Rollback Segment itself was corrupted, it's the bad of bad. If it's
not rbs, dropping object is more simple than other methods.
But, If rbs header is not corrupted, there is still a chance. It's possible to
identify uncomitted transactions and/or which corrupted
Hello Kevin,
I missed second part of your message:
case, dropping the objects will not do the trick because it will happen
again when the Rollback Segment is accessed for another activity.
coruupted rbs immediately should be dropped after fixing errors.
regards...
28/7/01 12:00:58, Kevin
I was able to do everything I needed by using undocumented/unsupported
_offline_rollback_segments parameter.
Rick
-Original Message-
Sent: Friday, July 27, 2001 1:37 PM
To: Multiple recipients of list ORACLE-L
Hi DBAs,
Oracle 8.0.5/Windows NT4
I shutdown database normal and
On Fri, 27 Jul 2001, Cale, Rick T (Richard) wrote:
Hi DBAs,
Oracle 8.0.5/Windows NT4
I shutdown database normal and restarted ok.
I tried to drop a rollback segment and getora-1545 rollback segment not
available.
When I select from dba_rollback_segs I get needs recovery.
I want to
have you backed up the database? done a full database export? just to be
careful
From: Cale, Rick T (Richard) [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Subject: RE: Rollback Segment needs recovery
Date: Fri, 27 Jul 2001 10:06:38
A long time ago Oracle support had me put this into my Init.ora file when I
had a bad Rollback segment that would not let go of a transaction.
_corrupted_rollback_segments=(RBS01) # Marks a
rollback segment corrupted so it can be dropped.
When I brought up the database I
Hello,
It's bad problem. I think _offline_rollback_segments or
_corrupted_rollback_segments should be last method.
I'll recommend a tip for this error: If you can identify which objects need
recovery and then drop them, Oracle doesn't try to recover them, so needs
recovery goes away.
Let's
Danisment;
When we had a problem that we needed the _corrupted_rollback_segments
option added to the init.ora file. The Rollback Segment itself was
corrupted. Not the objects using the Rollback Segment. If this is the
case, dropping the objects will not do the trick because it will happen
please do offline then drop
-Seema
From: Cale, Rick T (Richard) [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Subject: RE: Rollback Segment needs recovery
Date: Fri, 27 Jul 2001 10:06:38 -0800
I was able to do everything I needed
Kamel,
Looks like you may have had multiple transactions in your PL/SQL prg.
Since one transaction ended, the slot used by it to store undo information
was reused by other transactions. Your query did not find the required undo
information and thus Snapshot too old error. Had this been a long
Then everybody will use the one that's left.
[EMAIL PROTECTED] 03/02/01 11:45PM
Hi,
Anyone have idea, how Oracle8i make used of multiple rollback segments to
reduce system contention?
I am currently using 4 rollback segments what will happen if 3 of them are
offline?
:(
Thanxs,
--
It depends if the are public access or private.
Bottom line if you were using them actively, you will slow down since it
is likely the remaining segment will have to issue quite a few more extents
to keep up with activity.
Tim Sawmiller wrote:
Then everybody will use the one that's left.
If you drop 3 of your 4 rollback segments you will suffer in your database
ability to handle transactions. For a complete overview look here:
http://technet.oracle.com/doc/oracle8i_816/server.816/a76965/c02block.htm#84
01
That's it for now,
Mark
Mark Kirk
Working toward the Oracle DBA OCP
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