General - rollback segments

Been reading manuals, I have few question to clarify about rollback segments ( Lets leave undo tablespace and automatic undo management aside )
1) Rollback segments can be created in a tablespace - is there a max size/limit which could be specified for a rollback segment to use within a tablespace? - From reading manuals, the storage clause doesnt mention about max size/limt for a rollback segment; is it possible for rollback segment to fill-up tablespace (ummm due to some wired query[read consistency]/transaction) ?
2) We can create a separate rollback tablespace and have multiple rollback segments.
If there are 3 user tablespaces (T1/T2/T3), 1 rollback tablespace (RT).
- I create 1 rollback segment in tablespace T1, T2, T3
- I create 2 rollback segments in rollback tablespace RT
A user with "default tablespace T1" when running a transaction, which rollback segment will be used by this user (when rollback segment is not explicitly specified)?
Oracle-Student

user11359766 wrote:
Will the transaction spill over to the second rollback segment (i.e start using the 2nd rollback segment which is available and not being used by any other active transaction) or oracle will return an error since the first rollback segment assigned is filled up and the transaction is still active?This will be applied to both SMU and MMU.
From the same link above,
http://download.oracle.com/docs/cd/B10501_01/server.920/a96524/b_deprec.htm#634941
For the duration of a transaction, the associated user process writes rollback information only to the assigned rollback segment.I hope its self explanatory that the transaction can't roll over to any other roll back segment once its own gets out of space. In teh case of SMU also, if the undo datafile can't grow, your transaction would be stopped.
HTH
Aman....

Similar Messages

ROLLBACK SEGMENT CONTENTION 점검

제품 : ORACLE SERVER
작성날짜 : 1997-01-21
ROLLBACK SEGMENT CONTENTION 점검
================================
롤백 세그먼트는 트랜잭션의 before image 를 저장하기 위해 사용되어진다.
사용되어지는 롤백 세그먼트 양은 수행되는 operation의 특성이나 변화된 데이타
블럭에 의존한다.
각 트랜젝션은 롤백 관련 데이타를 writing 하기위해 가장 먼저 롤백 세그먼트
헤더에 있는 트랜젝션 테이블을 액세스하고 트랜잭션 테이블에 slot 을 얻는다.
이것은 동시에 update 되는 데이타를 write 하기 위해 테이블에 순간적인 Latch를
필요로 한다.
If the database is update intensive and has a small number of rollback segments,
user transactions will wait on the latch to access the transaction table.
A large number of rollback segments on a query intensive database will
result in wastage of space.
The following statistics shows interesting information on the rollback
segments.
It is generated from the view v$rollstat.
Before : create table stats$begin_roll as
select rownum undo#, rssize, gets, waits, writes
from v$rollstat;
After : create table stats$end_roll as
select rownum undo#, rssize, gets, waits, writes
from v$rollstat;
select e.gets - b.gets trans_tbl_gets, e.waits - b.waits trans_tbl_waits,
e.writes - b.writes undo_bytes_written,
e.rssize segment_size_bytes
from stats$begin_roll b, stats$end_roll e
where e.undo# = b.undo#;
Included below is the statistics collected for this section:
TRANS_TBL_GETS TRANS_TBL_WAITS UNDO_BYTES_WRITTEN SEGMENT_SIZE_BYTES
270 0 0 290016
2742 0 441585 4025986
614 0 32685 1508486
591 0 37831 1508486
In the above output, the waits on transaction table are zero.
If the ratio of Trans_tbl_waits to Trans_tbl_gets is greater than 5%,
additional rollback segments should be added to the database.
In general, rollback segments should be the same size and created with
a large number of small extents.
Occasionally, large transactions may enlarge rollback segments.
The database administrator should periodically verify this and
recreate them with equal extents.

I don't believe that a problem in your rollback segment can corrupt your backups, for checking if you have contention in the rollback segments you can run this query and review the results:
select class, count from v$waitstat where class like 'undo%';
These values should never be high
Hope this helps
Cynthia Pulido
Monterrey, Mexico

Persistent Rollback Segment Header Lockouts (8.1.6)

We are encountering the following situation on a 3-tier production system:
Users occasionally inadvertently disconnected from client tier while a long-standing transaction (individual inserts controlled manually) has not yet been committed. (client cannot rejoin the severred session, by the way).
At the point of disconnection, users often appear to be holding a rollback segment header enqueue.
Subsequently, other users are getting locked out by this enqueue as they go for a transaction.
We have 400 active users, and 80 rollback segments (ie. 5 potential transactions per segment). Each RBS is split into an minimum of 16 extents.
My question:
I have been led to believe by Oracle documentation that rollback seg. header locks are only held v. briefly. If this were so, the chances of this situation occurring would be slim. However, we observe this situation occurring daily.
Yes I can up the number of RBS, but is there some other action I could be taking ? - indeed upping the RBS count may have no appreciable impact on this situation at all !

Hi,
Generally "Snapshot too old " error occurs when your rollback segment has not enough space for keeping your undo information. If you still facing that problem even after assigning a big tablespace, means your transaction is taking so much space. You can try to assign some more space in tablespace where you ahve created rollback segment. Have you assigned the tablespace using the same syntax
SET TRANSACTION USE ROLLBACK SEGMENT large_rs1;
For getting more information on this pls go through the following link
http://download-uk.oracle.com/docs/cd/B10501_01/server.920/a96521/undo.htm#9114
Please let me know if you have any other issue.
Thanks

Maintenance on Rollback segments

Hello experts,
i need some pieces of advice.
1. Is there some maintenance that should be done regularly on my
Rollback segments?
2. Any guidelines for the creation of rollback segments?
3. how will i know if there is a contention on rollback segments?
thanks for your replies
regards
yogeeraj

Pretty large subject -- there are entire chapters written on
RBseg useage in various Oracle manuals.
In general (knowing you will take it upon yourself to start
reading up on RBsegs in the manuals):
1) I always create the largest RBsegs possible given a thorough
knowledge of the range of typical transactions. That way I spend
less time managing large queries from bone-head users who should
know better <grin>. On 8x systems use the ALTER ROLLBACK
SEGMENT... SHRINK on a periodic basis to release space to other
RBsegs.
FYI: RBsegs are going away in 9i, check out the new 9i UNDO
TBspace.
2) don't mix RBsegs with data and index space. Always put RBsegs
in their own tablespace to avoid TX contention. I always create
RBsegs with auto allocate TBS and datafiles.
3) way too much to say on the subject of RBseg contention but...
try to attain zero wait time on RBsegs. KNOW when your users are
running WHAT jobs and steer them towards run-times that favour
the entire DB resources.
RP.
Hello experts,
i need some pieces of advice.
1. Is there some maintenance that should be done regularly on my
Rollback segments?
2. Any guidelines for the creation of rollback segments?
3. how will i know if there is a contention on rollback segments?
>
>
thanks for your replies
regards
yogeeraj

Rollback segment Error coming for 8 lacks Record while creating MV

Hi All,
i am creating a materialized View and it gives us 8 lacks record but when we creates in production its fails due to rollback segment does not have enough space to handle it and it did not create the MV.
can anyone help me out to resolve this issue for the below query while creating MV.
SELECT DISTINCT NVL
((ROUND ((jt_date_completed - jt_date_requested) * 24, 2)
0
) AS actual_hrs_to_complete,
NVL ((ROUND ((jt_date_responded - jt_date_requested) * 24, 2)
0
) AS actual_hrs_to_respond,
peo1.peo_name AS agent_name,
peo1.peo_user_name AS asagent_soe_id,
le.lglent_desc AS ap_system,
' ' AS assign_work_request_comment,
DECODE (jt.jt_bill_id,
138802, 'CLIENT BILLABLE',
138803, 'CONTRACTED',
138804, 'INTERNAL BILLABLE',
NULL, ' '
) AS billable,
bl.bldg_name_cc AS building, bl.bldg_id_ls AS building_id,
DECODE (bl.bldg_active_cc,
'Y', 'ACTIVE',
'INACTIVE'
) AS building_status,
DECODE (jt.jt_wrk_cause_id,
141521, 'STANDARD WEAR AND TEAR',
141522, 'NEGLIGENCE',
141523, 'ACCIDENTAL',
141524, 'MECHANICAL MALFUNCTION',
141525, 'OVERSIGHT',
141526, 'VANDAL',
141527, 'STANDARD',
141528, 'PROJECT WORK',
6058229, 'TEST',
NULL, ' '
) AS cause_type,
' ' AS comments, peo3.peo_name AS completed_by,
jt.jt_requestor_email AS contact_email,
jt.jt_requestor_name_first
|| ' '
|| jt.jt_requestor_name_last AS contact_name,
jt.jt_requestor_phone AS contact_phone,
cc.cstctrcd_apcode AS corp_code,
cc.cstctrcd_code AS cost_center,
jt.jt_date_closed AS date_closed,
jt.jt_date_completed AS date_completed,
jt.jt_date_requested AS date_requested,
jt.jt_date_responded AS date_responded,
jt.jt_date_response_ecd AS date_response_ecd,
jt.jt_date_scheduled AS date_scheduled,
DECODE (jt.jt_def_id,
139949, 'WTG VENDOR RESPONSE',
139950, 'WAITING ON PARTS',
139951, 'LABOR AVAILABILITY',
139952, 'DEFERRED- HI PRI WORK',
139953, 'WTG APPROVAL',
139954, 'FUNDING REQUIRED',
139955, 'ACCESS DENIED',
139956, 'WTG MATERIAL',
NULL, ' '
) AS deferral_reason,
jt.jt_description AS description,
jt.jt_date_resched_ecd AS ecd,
fmg.facility_manager AS facility_manager,
fl.floors_text AS FLOOR, gl.genled_desc AS general_ledger,
' ' AS kiosk_date_requested, ' ' AS kiosk_dispatch_confirmed,
' ' AS kiosk_dispatched,
eqp.equip_customer_code AS linked_equipment_alias,
eqp.equip_id AS linked_equipment_id,
eqp.equip_text AS linked_equipment_name,
DECODE (jt_originator_type_id,
1000, 'PROJECT MOVE REQUEST',
138834, 'CUSTOMER INITIATED CORRECTION',
138835, 'CUSTOMER INITIATED REQUEST',
138836, 'CORRECTIVE MAINTENANCE',
138837, 'CONFERENCE ROOM BOOKING',
138838, 'PROJECT INITIATED REQUEST',
138839, 'PLANNED PREVENTIVE MAINTENANCE',
138840, 'SELF INITATED REQUEST',
NULL, ' '
) AS originator_type,
' ' AS payment_terms, priority_text AS priority_code,
swoty.sworktype_text AS problem_type,
prop.property_name_cc AS property,
jt.jt_cost_quote_total AS quote_total,
par.levels_name AS region,
DECODE (jt.jt_repdef_id,
141534, 'ADJUSTED SETTING',
141535, 'TRAINING FOR END',
141536, 'NEW REQUEST',
141537, 'NO REPAIR REQUIR',
141538, 'REPLACED PARTS',
141539, 'REPLACE EQUIPMEN',
1000699, 'NEW REQUEST',
NULL, ' '
) AS repair_definitions,
jt.jt_repairdesc AS repair_description,
jt.jt_requestor AS requestor, ' ' AS requestor_cost_center,
jt.jt_requestor_email AS requestor_email,
jt.jt_requestor_name_first AS requestor_name,
jt.jt_requestor_phone AS requestor_phone,
' ' AS response_time, rm.room_name_cc AS room,
p1.peo_provider_code1 AS service_provider,
p1.peo_address_1 AS service_provider_address,
peocity.city_text service_provider_city,
p1.peo_provider_code1 AS service_provider_code,
peocity.city_country_name AS service_provider_country,
peocur.currency_text AS service_provider_currency,
p1.peo_name AS service_provider_description,
p1.peo_dispatch_method AS serv_prov_dispatc_hmethod,
p1.peo_rate_double AS serv_prov_double_time_rate,
p1.peo_email AS service_provider_email,
p1.peo_emergency_phone AS serv_prov_emergency_phone,
p1.peo_fax AS service_provider_fax_number,
p1.peo_home_phone AS service_provider_home_phone,
p1.peo_rate_hourly AS service_provider_hourly_rate,
p1.peo_title AS service_provider_job_title,
p1.peo_method_id AS service_provider_method,
p1.peo_cell_phone AS service_provider_mobile_phone,
p1.peo_pager AS service_provider_pager,
p1.peo_rate_differential AS service_provider_rates,
p1.peo_rate_differential AS ser_prov_shift_differential,
peocity.city_state_prov_text AS serv_prov_state_province,
DECODE (p1.peo_active,
'Y', 'ACTIVE',
'INACTIVE'
) AS service_provider_status,
p1.peo_url AS serv_prov_web_site_address,
p1.peo_phone AS service_provider_work_phone,
p1.peo_postal_code AS serv_prov_zip_postal_code, ' ' AS shift,
' ' AS skill,
DECODE (jt.jt_bigstatus_id,
138813, 'NEW',
138814, 'PENDING',
138815, 'OPEN',
138816, 'COMPLETED',
138817, 'CLOSED',
138818, 'CANCELLED',
NULL, ' '
) AS status,
lev.levels_name AS subregion, ' ' AS trade,
p1.peo_ls_interface_code1 AS vendor_id,
p1.peo_fax AS vendor_purchasing_fax,
p1.peo_vendor_site_code AS vendor_sitecode,
jt.jt_id AS vendor_ticket, p1.peo_name AS vendor_companyname,
jt.jt_requestor_vip AS vip, wo.wo_id AS work_order_no,
jt.jt_id AS work_request,
jt.jt_class_id AS work_request_class,
woty.worktype_text AS work_type, ' ' AS wr_cost,
jt.jt_description AS wr_description,
' ' AS wr_dispatch_method,
DECODE (jt.jt_bigstatus_id,
138813, 'NEW',
138814, 'PENDING',
138815, 'OPEN',
138816, 'COMPLETED',
138817, 'CLOSED',
138818, 'CANCELLED',
NULL, ' '
) AS wr_status,
ctry.country_name AS country
FROM citi.jobticket jt,
citi.property prop,
citi.bldg bl,
citi.bldg_levels bldglvl,
citi.LEVELS lev,
citi.LEVELS par,
(SELECT crstools.stragg (peo_name) facility_manager,
bldgcon_bldg_id
FROM citi.bldg_contacts, citi.people
WHERE bldgcon_peo_id = peo_id
AND bldgcon_contype_id IN (40181, 10142)
GROUP BY bldgcon_bldg_id) fmg,
citi.floors fl,
citi.room rm,
citi.general_ledger gl,
citi.legal_entity le,
citi.cost_center_codes cc,
citi.equipment eqp,
citi.worktype woty,
citi.subworktype swoty,
citi.work_order wo,
citi.jt_workers jtwo,
citi.priority,
citi.country ctry,
citi.people p1,
citi.people peo3,
citi.people peo1,
citi.city peocity,
citi.currency peocur
WHERE jt.jt_bldg_id = bl.bldg_id
AND bl.bldg_id = bldglvl.bldg_levels_bldg_id
AND bldglvl.bldg_levels_levels_id = lev.levels_id
AND lev.levels_parent = par.levels_id(+)
AND prop.property_id = bl.bldg_property_id
AND bl.bldg_active_ls <> 'N'
AND jt.jt_floors_id = fl.floors_id(+)
AND jt.jt_room_id = rm.room_id(+)
AND jt.jt_bldg_id = fmg.bldgcon_bldg_id(+)
AND jt.jt_genled_id = gl.genled_id(+)
AND gl.genled_lglent_id = le.lglent_id(+)
AND jt.jt_cstctrcd_id = cc.cstctrcd_id(+)
AND jt.jt_equip_id = eqp.equip_id(+)
AND jt.jt_id = jtwo.jtw_jt_id(+)
AND jt.jt_worktype_id = woty.worktype_id(+)
AND jt.jt_sworktype_id = swoty.sworktype_id(+)
AND jt.jt_wo_id = wo.wo_id
AND jt.jt_priority_id = priority_id(+)
AND jt.jt_date_requested >= ADD_MONTHS (SYSDATE, -12)
AND bl.bldg_country_id = ctry.country_id
AND jtwo.jtw_peo_id = p1.peo_id(+)
AND p1.peo_city_id = peocity.city_id(+)
AND jt.jt_completed_by_peo_id = peo3.peo_id(+)
AND p1.peo_rate_currency_id = peocur.currency_id(+)
AND jt.jt_agent_peo_id = peo1.peo_id(+);
Regards
shyam~

Hi,
Its ora-1555? IS your undo_retention sufficient?
Since you are developer the only option you have is to tune the query?
Am curious to know like I create materialized view so that I do not have to run complex query on the master database / or to prevent the access to master database more than once to get the same data?
Like to know which is your case because your query seem to be too complex to be the case for former. Do you think this materialized view would be used frequently in your application?
Regards
Anurag Tibrewal.

Forcing a specific rollback segment on a transaction does not seem to work

Hi!
We're using Oracle 9.2.0.5.0 on Sun Solaris and we're still configured to use Rollback Segments.
We have an issue with Snapshot too old due to RBS too small on a long query I attach below for reference:
set heading off
set pagesize 0
set feedback off
set linesize 200
<<<<< SET TRANSACTION USE ROLLBACK SEGMENT UMF_RBS_LARGE_TRAN; <<<<<
SELECT ucms_cards.msisdn
|| ';;' || to_char(to_date(substr(ucms_cards.notes,14+length(ucms_cards.msisdn),19),'MM-DD-YYYY.HH24-MI-SS'),'DD/MM/YYYY HH24:MI:SS')
|| ';;' || to_char(ucms_batches.expiry_date,'dd/mm/yyyy')
|| ';;' || ucms_cards.serial_no
|| ';;' || ucms_cards.serial_no
|| ';;' || ucms_cards.batch_serial_no
|| ';;' || ' '
|| ';;' || CASE ucms_cards.card_status
WHEN 'used' THEN '1'
ELSE '0'
END
|| ';;' || CASE WHEN date_booked_in is null THEN '01/01/1970 00:00:00' ELSE to_char(date_booked_in,'DD/MM/YYYY') || ' 00:00:00' END
|| ';;' || ' '
from ucms_batches,ucms_cards, UCMS_EVENT_LOG
WHERE ucms_cards.batch_serial_no = ucms_batches.serial_no
AND ucms_cards.serial_no = substr(UCMS_EVENT_LOG.ENTITY_ID,11,length(UCMS_EVENT_LOG.ENTITY_ID)-9)
AND UCMS_EVENT_LOG.PARTY_NO in (0)
AND UCMS_EVENT_LOG.TIMESTAMP>=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 00:00:01', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.TIMESTAMP<=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 23:59:59', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.USER_ID LIKE 'SCP-AGENT1%'
AND UCMS_EVENT_LOG.EVENT_TYPE_ID IN (1,2)
AND UCMS_EVENT_LOG.ENTITY_TYPE_ID LIKE 'ucms_cards%'
UNION
SELECT ucms_imported_cards.msisdn
|| ';;' || to_char(to_date(substr(ucms_imported_cards.notes,14+length(ucms_imported_cards.msisdn),19),'MM-DD-YYYY.HH24-MI-SS'),'DD/MM/YYYY H24:MI:SS')
|| ';;' || to_char(ucms_imported_cards.expiry_date,'dd/mm/yyyy')
|| ';;' || ucms_imported_cards.serial_no
|| ';;' || ucms_imported_cards.serial_no
|| ';;' || DBMS_UTILITY.GET_HASH_VALUE(ucms_imported_cards.card_type,1,65536)
|| ';;' || ' '
|| ';;' || CASE ucms_imported_cards.card_status
WHEN 'used' THEN '1'
ELSE '0'
END
|| ';;' || '01/01/1970 00:00:00'
|| ';;' || ' '
from ucms_imported_cards, UCMS_EVENT_LOG
where ucms_imported_cards.serial_no = substr(UCMS_EVENT_LOG.ENTITY_ID,11,length(UCMS_EVENT_LOG.ENTITY_ID)-9)
AND UCMS_EVENT_LOG.PARTY_NO in (0)
AND UCMS_EVENT_LOG.TIMESTAMP>=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 00:00:01', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.TIMESTAMP<=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 23:59:59', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.USER_ID LIKE 'SCP-AGENT1%'
AND UCMS_EVENT_LOG.EVENT_TYPE_ID LIKE '2%'
AND UCMS_EVENT_LOG.ENTITY_TYPE_ID LIKE 'ucms_imported_cards%';
As you see we forced the session to use a huge RBS created for the purpose, but strangely after a long while the query fails with a RBS too small failure due to another RBS, not the one specified.
Is there any chance the UNION or any other component of the query is implicitly opening a new transaction with a different RBS associated?
Any chance to force the same RBS specified explicitly?
Thanks!
Mike

albertone wrote:
but strangely after a long while the query fails with a RBS too small failure due to another RBS, not the one specified.You misunderstand snapshot too old. It can be caused by other sessions same as by your session. Assume AFTER your session issued select some other session modified one (or more) tables ucms_batches, ucms_cards, UCMS_EVENT_LOG and committed changes. By the time your select reaches to fetch rows modified by that other session rollback extents in rollback segment used by that other session were reused. You will get snapshot too old. Bottom line - all sessions modifying table(s) used by your select must use rollback segments large enough so they are not overwritten before corresponding rows are needed by your select.
SY.

Views Status at MARA general info segment level

Hi all,
Please guide me how to maintain Views Status at MARA general info segment level.I am extending standard MATMAS IDOC for my own fields.
Thank you.

You actually need to run it with "check -access"; memuse and leaks won't help with the crash, which happens because of illegal memory access. Hopefully, "check -access" will help you to locate the bad guy, but that's not panacea either.
To be precise:
- start dbx
$ dbx <your app>
- issue
(dbx) check -access
(dbx) run
and wait for dbx to stop and report suspicious memory access.

Error while creating the rollback segment (Oracle 8i & OS Win NT)

hi
I am using Oracle 8i and when i am creating the new rollback segment for my database i have got following error message
ORA-01593 Rollback segment optimal size (30 blks) is smaller than the computed initial size (2560 blks)
CREATE ROLLBACK SEGMENT "RBS11" TABLESPACE "RBS1"
STORAGE ( INITIAL 120K NEXT
120K OPTIMAL
240K MINEXTENTS 2
MAXEXTENTS 100)
Note:- db_block size is 8k
Tablespace RBS1 is the Locally managed Tablespace having datafile of 50m and uniform size of 10m
But Given statement processed while i am using Tablespace RBS (winch is data dictionary managed)
Plz, suggest me to cause of that error and solution

You said 120K optimal and initial is 120K with minextents of 2. The optimal size then will be smaller than the initial allocation for the rbs.
ORA-01593: rollback segment optimal size (string blks) is smaller than the computed initial size (string blks)
Cause: Specified OPTIMAL size is smaller than the cumulative size of the initial extents during create rollback segment.
Action: Specify a larger OPTIMAL size.

Error rollback segment while exporting a table

I am getting error while exporting a table, can someone advise me how i can handle this issue.
EXP-00056: ORACLE error 1555 encountered
ORA-01555: snapshot too old: rollback segment number with name "" too small
ORA-22924: snapshot too old
Thanks

Hi, I have the same problem...
I have a table with a blob type (14740 records)
I have increase the PCTVERSION to 100 (= maximum)
undo_retention = 604800 (7 days)
undo tablespace = 2 Gb
exporting with parameter CONSISTENT=n
Still I got the message
EXP-00056: ORACLE error 1555 encountered
ORA-01555: snapshot too old: rollback segment number with name "" too small
ORA-22924: snapshot too old
When exporting the table
What do I have to do more ?????

Rollback segment is filling up during creation of the database

Hi
The Rollback segment is showing around 520mb immediately after
creation of the database after following the wizard provided in
the enterprise manager of oracle. What might be the reason. How
to reduce it. Could any one give me a solution for this matter.
Thanks in Advance.

I tried creating the password file using the following command:
orapwd file=/home/oracle/product/9.2.0/dbs/orapwHR.ora
password=HR entries=5
and got the same error:
ORA-01501 Create Database failed.
ORA-01990 -ERROR opening password file '/home/oracle/product/9.2.0/dbs/orapw'
ORA-27037 Unable to obtain file status.
Linux error: 2: No such file or directory.
Additional information: 3.
Does anybody know how to fix this problem?
Thanks,
Katya

How to get the size of rollback segments

Hi,
on which oracle table can I see which are the rollback segments and its own size?
Thanks!

doc questions like this one are best answered by querying the view DICT which is present in every release of Oracle (and which you of course -again- fail to mention)
Sybrand Bakker
Senior Oracle DBA

Trying to understand rollback segments - offline tblspaces for backup

Using Oracle 8i, on Windows platform - The question - receive an error ORA-01556 when performing a
sql "ALTER TABLESPACE MY_TBS_LT OFFLINE IMMEDIATE";
=============================================
First off I created a tablespace and table on an 8i database.
create tablespace my_tbs_lt_tbs_lt
datafile '&&2\oradata\&&1\my_tbs_lt_guitest1.dbf'
size 10M
AUTOEXTEND ON NEXT 1280k EXTENT MANAGEMENT LOCAL UNIFORM SIZE 128K; <===== Is this right for use with rollback segments?
CREATE ROLLBACK SEGMENT rbgui1t2 STORAGE(INITIAL 50K NEXT 250K)
tablespace my_tbs_lt;
CREATE ROLLBACK SEGMENT rbgui2t2 STORAGE(INITIAL 50K NEXT 250K)
tablespace my_tbs_lt;
CREATE ROLLBACK SEGMENT rbgui3t2 STORAGE(INITIAL 50K NEXT 250K)
tablespace my_tbs_lt;
CREATE ROLLBACK SEGMENT rbgui4t2 STORAGE(INITIAL 50K NEXT 250K)
tablespace my_tbs_lt;
-- Bring new rollback segments online
ALTER ROLLBACK SEGMENT rbgui1t2 ONLINE;
ALTER ROLLBACK SEGMENT rbgui2t2 ONLINE;
ALTER ROLLBACK SEGMENT rbgui3t2 ONLINE;
ALTER ROLLBACK SEGMENT rbgui4t2 ONLINE;
CREATE TABLE guitester.guitester_t2
( employee_id NUMBER(6)
, first_name VARCHAR2(20)
, last_name VARCHAR2(25)
CONSTRAINT emp_last_name_nn_demo NOT NULL
, email VARCHAR2(25)
CONSTRAINT emp_email_nn_demo NOT NULL
, phone_number VARCHAR2(20)
, hire_date DATE DEFAULT SYSDATE
CONSTRAINT emp_hire_date_nn_demo NOT NULL
, job_id VARCHAR2(10)
CONSTRAINT emp_job_nn_demo NOT NULL
, salary NUMBER(8,2)
CONSTRAINT emp_salary_nn_demo NOT NULL
, commission_pct NUMBER(2,2)
, manager_id NUMBER(6)
, department_id NUMBER(4)
, dn VARCHAR2(300)
, CONSTRAINT emp_salary_min_demo
CHECK (salary > 0)
tablespace my_tbs_lt;
=======================================
I changed the initSID.ora file to have
Rollback_segments=( rbgui1t2, rbgui2t2, rbgui3t2, rbgui4t2)
=======================================
restarted everything
========================================
did a backup of the tablespace my_tbs_lt;
========================================
added some data to the table in the tablespace
========================================
ran a restore/recover - Get the error
========================================
It makes sense that I get the error because it is the tablespace that I have been working with, adding data. Is my logic correct? How does one restore a tablespace if it has rollback segments active? Can someone look to make sure I am declaring the rollback segments appropriately?

Thank you for the link - very helpful.
So would a more appropriate scheme be:
Create a tablespace
Create rollback segments
Put them online
enter their names in the ROLLBACK_SEGMENTS= segment(s)
I havent read everything, so you may say go look at the link again, but a second question. If you are managing the extent locally, does it not use a rollback segments, or is it using system, or is it actually creating rollback segments for itself within the context of the local management?
In my above scenario, I would have to take my rollback segment offline as well as the tablespace.

Rollback segment creation problem

When i try to create rollback segment on oracle 9iRelease2 database in linux operating system, i got the following error, ORA-30019: Illegal rollback Segment operation in Automatic Undo mode.
I have already modified Undo_management as manual in init file.
How can i solve this problem?
Thanks

In SQL*Plus, can you check what your undo_management is set to, just to verify that it is picking up the change?
show parameter undo_managementJustin
Distributed Database Consulting, Inc.
www.ddbcinc.com/askDDBC

Rollback segment problem

Hello:
I'm using oracle 8 database and I have a process that generates small transactions (and they're really small), usually this process is executed from 2 or 3 different workstations at the same time, but they don't use the same data sets. The frequency of execution of the small transaction is 10 or 12 a second for each workstation. Each time the process is executed I can count near 6000 transactions, and I always have 2 o 3 of them arising "ORA-01562: failed to extend rollback segment number n" error. Since the transaction uses a small space of the rollback segment I can't find an explanation to this behavior. Is this related to the time between transaction and the freeing of the unused rollback segment ? I would really appreciate if somebody could help me!!!
Thanks in advance, Javier Petrozzi

It appears to me that some of the transactions remain open for quite some time and the new transactions are not able to obtain an extent for the rollback segment.
The following query gives some useful information.
1 select s.sid, s.username, r.name "SEGMENT NAME"
2 from v$session s, v$transaction t, v$rollname r
3 where s.taddr=t.addr
4* and t.xidusn = r.usn
SQL> /
SID USERNAME SEGMENT NAME
16 SCOTT _SYSSMU7$You may have to commit your changes sooner.

Rollback segment problem during import

Hello experts,
please help.
I have the following error when importing table data to my
Oracle 8.1.7 database.
IMP-00058: ORACLE error 1562 encountered
ORA-01562: failed to extend rollback segment number 16
ORA-01237: cannot extend datafile 3
kind regards
Yogeeraj

alter the tablespace which contains rollback segments, and
either change the existing datafile (datafile 3) to autoextend
on or resize, or add new datafile in another disk drive which
has more space (it is better to set autoextend on or give it a
larger space).
Hello experts,
please help.
I have the following error when importing table data to my
Oracle 8.1.7 database.
IMP-00058: ORACLE error 1562 encountered
ORA-01562: failed to extend rollback segment number 16
ORA-01237: cannot extend datafile 3
kind regards
Yogeeraj

General - rollback segments

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