Space management oracle

Hi all,
Greetings of the day..
I have few doubts about the space management in ASSM tablespace.
1.Does ALTER TABLE SHRINK COMPACT needs ALTER TABLE ENABLE ROW MOVEMENT to be fired prior
2. I have table having fragmentation and materialized views on top of it updating with ROWID' s , how can i defragment the table without dropping the MVS
Thanks,
Uday

I'm not sure what you're showing here. Is this showing why you believe the table is fragmented? It shows that the table has some reclaimable space. That's not normally what people are concerned about when they talk about "fragmentation".
Note that if you use the \ tag (6 characters, all lower case) before and after cutting and pasting fixed format data (such as the output of SQL statements), you'll preserve the white space and make your posts much easier to read.
Justin

Similar Messages

Oracle Free Space Management

Is Free Space Management a Initialization Parameters,
if so which one,
Where is Free Space Management keepth ?
Eric

Eric, Free space management is not a database parameter. You should read the Concepts manual. It explains Tablespace management and object management basics. Or you can see the chapters devoted to Tablespace and Object management in the DBA Administration Guide for a more detailed analysis.
To find free space in the database see the dictionary view: dba_free_space.
To how space management is handled for a tablespace see the dictionary view: dba_tablespaces.
HTH -- Mark D Powell --

ASSM (Automatic Segment Space Management)

Hi Folks.
I have a severe problem regarding Buffer Busy Waits.
I have deceided to implement ASSM (Automatic Segment Space Management).
Please assist....is the approch OK & how should i apply this in a existing tablespace (pls also specify the syntax & other constraints that should be taken care of)....
Waiting for reply ... & thanks a lot in advance....

ASSM is a good feature to use, but, you need to kill the culprit instaed of simply MOVING ON.
If creating a new tablespace with ASSM, moving objects from Non-ASSM to the new tablespace is a problem, then, think of the following:
First of all, findout which object type is causing BBW, is it rollback/undo header, undo/rollback block, segment headere or what?
You need to review the P3 value(reason code) of BBW wait event.
Try to review the following dynamic views, before you decide to MOVE on.
v$waitstat (segment header)
v$segment_statistics(read the oracle docs. how to use this view and which parameter need to set in order to enable this feature).
Jaffar

Alter SHRINK SPACE in oracle 10g

Hello,
My table PRICE_T table gets deleted and inserted almost 50 million records everyday.
Now it takes too much time to perform this operation because of TABLE fragmented.
i can use "CREATE table as select” option to remove fragmentation from table.
but i dont want to use this option.
so i hv tried ALTER TABLE SHRINK SPACE as i m using ORACLE 10g
alter table price_t enable row movement;
alter table price_t shrink space
alter table price_t disable row movement;
and i have applied following query to check table gets remove free space but still having free space after applying ALTER SPACE COMMAND
select table_name,round((blocks*8),2)||'kb' "size1",round((num_rows*avg_row_len/1024),2)||'kb' "size"
from DBA_tables
where table_name = 'PRICE_T';
Tablespace in PRICE_T table fall into is SEGMENT SPACE MANAGEMENT AUTO
please help me to remove fragmentation from table using SHRINK command.
Thanks.

Now it takes too much time to perform this operation because of TABLE fragmented.How do you define "fragmented"?
Why do you believe that your table is fragmented?
Why do you believe that the fragmentation is causing performance problems?
select table_name,
round((blocks*8),2)||'kb' "size1",
round((num_rows*avg_row_len/1024),2)||'kb' "size"
from DBA_tables
where table_name = 'PRICE_T'; - What is the output of this query before and after you shrink the table?
- Are your statistics up to date? NUM_ROWS, BLOCKS and AVG_ROW_LENGTH provide information to the optimizer-- they are estimates gathered when object statistics are gathered. They are not maintained by Oracle in real time and may be substantially out of date.
- I don't see any attempt to account in this query for overhead like PCTFREE.
- Is there a reason that you aren't using the DBMS_SPACE package? This query seems highly suspect.
Justin

Problem about space management of archived log files

Dear friends,
I have a problem about space management of archived log files.
my database is Oracle 10g release 1 running in archivelog mode. I use OEM(web based) to config all the backup and recovery settings.
I config "Flash Recovery Area" to do backup and recovery automatically. my daily backup schedule is every night at 2:00am. and my backup setting is "disk settings"--"compressed backup set". the following is the RMAN script:
Daily Script:
run {
allocate channel oem_disk_backup device type disk;
recover copy of database with tag 'ORA$OEM_LEVEL_0';
backup incremental level 1 cumulative copies=1 for recover of copy with tag 'ORA$OEM_LEVEL_0' database;
the retention policy is the second choice, that is "Retain backups that are necessary for a recovery to any time within the specified number of days (point-in-time recovery)". the recovery window is 1 day.
I assign enough space for flash recovery area. my database size is about 2G. I assign 20G as flash recovery area.
now here is the problem, through oracle online manual, it said oracle can manage the flash recovery area automatically, that is, when the space is full, it can delete the obsolete archived log files. but in fact, it never works! whenever the space is full, the database will hang up! besides, the status of archived log files is very strange, for example, it can change "obsolete" stauts from "yes" to "no", and then from "no" to "yes". I really have no idea about this! even though I know oracle usually keep archived files for some longer days than retention policy, but I really don't know why the obsolete status can change automatically. although I can write a schedule job to delete obsolete archived files every day, but I just want to know the reason. my goal is to backup all the files on disk and let oracle automatically manage them.
also, there is another problem about archive mode. I have two oracle 10g databases(release one), the size of db1 is more than 20G, the size of db2 is about 2G. both of them have the same backup and recovery policy, except I assign more flash recovery area for db1. both of them are on archive mode. both of nearly nobody access except for the schedule backup job and sometime I will admin through oem. the strange thing is that the number of archived log files of smaller database, db2, are much bigger than ones of bigger database. also the same situation for the size of the flashback logs for point-in-time recovery. (I enable flashback logging for fast database point-in-time recovery, the flashback retention time is 24 hours.) I found the memory utility of smaller database is higher than bigger database. nearly all the time the smaller database's memory utility keeps more than 99%. while the bigger one's memory utility keeps about 97%. (I enable "Automatic Shared Memory Management" on both databases.) but both database's cup and queue are very low. I'm nearly sure no one hack the databases. so I really have no idea why the same backup and recovery policy will result so different result, especially the smaller one produces more redo logs than bigger one. does there anyone happen to know the reason or how should I do to check the reason?
by the way, I found web based OEM can't reflect the correct database status when the database shutdown abnormally. for example, if the database hang up because of out of flash recovery area, after I assign more flash recovery area space and then restart the database, the OEM usually can't reflect the correct database status. I must restart OEM manually to correctly reflect the current database status. does there anyone know in what situation I should restart OEM to reflect the correct database status?
sorry for the long message, I just want to describe in details to easy diagnosis.
any hint will be greatly appreciated!
Sammy

thank you very much, in fact, my site's oracle never works about managing archive files automatically although I have tried all my best. at last, I made a job running daily to check the archive files and delete them.
thanks again.

Migration LONG to LOB in manual space management tablespaces

Hi everyone,
We have Netweaver 7.0 and Oracle 11g and we are considering to migrate our manual tablespaces to ASSM. The first problem we've found is we can't do that online due to the LONG data type. So we decided to migrate LONG to LOB first. Note 835552 says that for Oracle version 11g the conversion is from LONG to SECUREFILE. But we follow seeking notes and in 1426979 (Oracle 11g: SecureFiles - The new way to store LOB data) one of the prerequisites for the conversion is to use ASSM tablespaces.
At this point, we can't migrate (online) to ASSM due to LONG data and neither can migrate to SECUREFILE due to the ASSM.
My question is: is it possible to make the migration from LONG to SECUREFILE specifying in the brspace a new tablespace with ASSM?
Thanks in advanced.

Hello
It is in fact possible to reorganize segment to a specific target tablespace using brspace option -n|-newts
brspace -u / -f tbreorg -a long2lob -o sapsr3 -s <source_tablesapce> -t allsel -n <target_tablespace_in_ASSM>
It is odd that in 11g you are not in ASSM, so you upgrade to that version and never performed tablespace reorg ?
620803 - Oracle 9i: Automatic Segment Space Management
The new ASSM function is available as of Oracle Release 9i. As of Oracle 10g, ASSM is already contained in the standard system, and new tablespaces are by default created as ASSM tablespaces.
Regards

How SMON coalesces free space in oracle 9i and 10g

how SMON coalesces free space in oracle 9i and 10g?
Is it doing same as it was behaving in oracle 7 like looking through free extent table every five minutes (sys.fet$) to see if there are any adjacent free extents that can be coalesced into a single extent, and on every 25th cycle (i.e. every two hours and five minutes) it looks at the segment table (sys.seg$) to see if there are any temporary segments that need to be eliminated, as explained by jonathan lewis?
what are extent and segment tables available in oracle 9i and 10g like sys.fet$ and sys.seg$ in oracle7?

>
how SMON coalesces free space in oracle 9i and 10g?
Is it doing same as it was behaving in oracle 7 like looking through free extent table every five minutes (sys.fet$) to see if there are any
adjacent free extents that can be coalesced into a single extent, and on every 25th cycle (i.e. every two hours and five minutes) it looks
at the segment table (sys.seg$) to see if there are any temporary segments that need to be eliminated, as explained by jonathan lewis?
what are extent and segment tables available in oracle 9i and 10g like sys.fet$ and sys.seg$ in oracle7?I think you need to go and have a look at the Oracle 9i documentation here
http://www.oracle.com/technology/documentation/oracle9i_arch_901.html
and automatic segment management in 10g
http://www.oracle.com/technology/pub/articles/10gdba/week15_10gdba.html
HTH.
Paul...
Software - OS (+ version), Server,
Hardware - CPU + Disk configuration.
Please include all of the above information with database queries.
This will help those who are trying to help you!
Furthermore, please do not top-post and do try to trim your replies!

Roblem about space management of archived log files

Dear friends,
I have a problem about space management of archived log files.
my database is Oracle 10g release 1 running in archivelog mode. I use OEM(web based) to config all the backup and recovery settings.
I config "Flash Recovery Area" to do backup and recovery automatically. my daily backup schedule is every night at 2:00am. and my backup setting is "disk settings"--"compressed backup set". the following is the RMAN script:
Daily Script:
run {
allocate channel oem_disk_backup device type disk;
recover copy of database with tag 'ORA$OEM_LEVEL_0';
backup incremental level 1 cumulative copies=1 for recover of copy with tag 'ORA$OEM_LEVEL_0' database;
the retention policy is the second choice, that is "Retain backups that are necessary for a recovery to any time within the specified number of days (point-in-time recovery)". the recovery window is 1 day.
I assign enough space for flash recovery area. my database size is about 2G. I assign 20G as flash recovery area.
now here is the problem, through oracle online manual, it said oracle can manage the flash recovery area automatically, that is, when the space is full, it can delete the obsolete archived log files. but in fact, it never works! whenever the space is full, the database will hang up! besides, the status of archived log files is very strange, for example, it can change "obsolete" stauts from "yes" to "no", and then from "no" to "yes". I really have no idea about this! even though I know oracle usually keep archived files for some longer days than retention policy, but I really don't know why the obsolete status can change automatically. although I can write a schedule job to delete obsolete archived files every day, but I just want to know the reason. my goal is to backup all the files on disk and let oracle automatically manage them.
also, there is another problem about archive mode. I have two oracle 10g databases(release one), the size of db1 is more than 20G, the size of db2 is about 2G. both of them have the same backup and recovery policy, except I assign more flash recovery area for db1. both of them are on archive mode. both of nearly nobody access except for the schedule backup job and sometime I will admin through oem. the strange thing is that the number of archived log files of smaller database, db2, are much bigger than ones of bigger database. also the same situation for the size of the flashback logs for point-in-time recovery. (I enable flashback logging for fast database point-in-time recovery, the flashback retention time is 24 hours.) I found the memory utility of smaller database is higher than bigger database. nearly all the time the smaller database's memory utility keeps more than 99%. while the bigger one's memory utility keeps about 97%. (I enable "Automatic Shared Memory Management" on both databases.) but both database's cup and queue are very low. I'm nearly sure no one hack the databases. so I really have no idea why the same backup and recovery policy will result so different result, especially the smaller one produces more redo logs than bigger one. does there anyone happen to know the reason or how should I do to check the reason?
by the way, I found web based OEM can't reflect the correct database status when the database shutdown abnormally. for example, if the database hang up because of out of flash recovery area, after I assign more flash recovery area space and then restart the database, the OEM usually can't reflect the correct database status. I must restart OEM manually to correctly reflect the current database status. does there anyone know in what situation I should restart OEM to reflect the correct database status?
sorry for the long message, I just want to describe in details to easy diagnosis.
any hint will be greatly appreciated!
Sammy

thank you very much, in fact, my site's oracle never works about managing archive files automatically although I have tried all my best. at last, I made a job running daily to check the archive files and delete them.
thanks again.

DB02:Space management/Segments/Most allocated extents in any segment

Hi ,
in My SAP server: DB02 > Oracle Database Administration > Alerts > Alert monitor, there are few red alerts.
1. Space management > Segments >Most allocated extents in any segment 263 > 200 - 263 > 200: number of extents > threshold 03.03.2009 09:35:46
in RZ20 Most allocated extents in any segment having thersold value :200
Can anybody knows what it is about? How to fix this? And what are the risks if I ignore this?
with Regards
Harinatha Reddy M

Hi,
What is your Oracle database version.? If it is 9i or 10g then you can ignore this warning as from Oracle uses Localy managed Tablespaces.
Please check below mentioned SAP notes, it may help you.
Note 599694 - LMTS autoallocate: Extent allocation
Note 706625 - Oracle9i: Locally managed SYSTEM tablespace
Note 214995 - Oracle locally-managed tablespaces in the SAP environment
Thanks,
Sushil

How to change segment space management (to manual)

How do I change the segment space management for a tablespace, from auto to manual
I can find documentation, to create tablespaces, and set them to auto, but nothing yet to change them from auto to manual.

I just found out, that I am confusing 2 subjects here: segment space management, and auto extensibility. My apologies ....... still new with Oracle :-o
Ok, to change autoextend to manual, do I do this on data_file level ? Do I only need to change this on the last datafile of a tablespace ?

UNDO table space in oracle

Hi,
Recently i have added one data file(2GB) to undo table space.Later i gog to know it is not recommend to extent the undo table space.In oracle 9i undo management is handle automatically.(in my init<SID>.ora file undo_management='AUTO')
I have 3 data file undo_1,undo_2,undo_3.
undo_2 is the datafile of 2Gb that i have added.
My question is ....is there any possibility to remove that data file from the DB(undo_2) if possible how can i dod that.
Pls help me.
roshantha

SQL> show parameter undo
NAME TYPE VALUE
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL>
SQL>
##FIRST : CREATE AN ANOTHER TEMPORARY UNDO TABLESPACE FOR YOUR DATABASE USERS.
SQL> create undo tablespace UNDOTBS_TEMP datafile 'c:\undotbs_temp1.dbf' size 2G;
Tablespace created.
SQL> show parameter undo
SQL> alter system set undo_tablespace=UNDOTBS_TEMP;
System altered.
SQL> show parameter undo
NAME TYPE VALUE
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS_TEMP
##NOW DROP YOUR UNWANTED TABLESPACE INCLUDING DATAFILES
SQL> drop tablespace undotbs1;
Tablespace dropped.
SQL> drop tablespace undotbs2 including contents and datafiles;
Tablespace dropped.
##NOW RECREATE THE UNDOTBS and RUSE THE FILE YOU WANTED TO
SQL> create undo tablespace UNDOTBS1 datafile 'C:\ORACLE\PRODUCT\10.1.0\ORADATA\ORCL\UNDOTBS01.DBF' reuse;
Tablespace created.
SQL> alter system set undo_tablespace=UNDOTBS1;
System altered.
SQL> show parameter undo
NAME TYPE VALUE
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL>
hope it helps :-)
Thanks,
Z

Segment space management

hai experts
can anyone tell me the reason why system tablespace's segment space management is manual. any link for the description

thanks Jonathan Ferreira
want to know why manual management is made as
default for system tablespace
hen auto space management will reduce the burden of a
DBA and make space management easyIf I had to make a guess, I would suggest that since the system tablespace contains rollback (undo) segments, ASSM cannot be used. With ASSM, the extent size starts small (64KB) and grows to 1MB, 8MB, etc. as additional extents are added to segments.
Since regular users should not be using the SYSTEM tablespace for inserts/updates/undo, there should be minimal burden for the DBA in managing that tablespace.
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.

BRTools (Space Management)

Dear All,
We are facing Space problem in one drive. So I am trying to move datafile from one drive to another.
So I am following the step
Eg.F:\oracle\ DAS\sapdata4\DAS_39\*DAS.DATA39*
We are trying to move DAS.DATA39 data file from F drive to I drive do am following step
Start BRTools, select option 2 (Space Management) then option 6 (Move data file)
And option 4(Data file name)
u201CDAS.DATA39u201D
after this what I have to give what are the further next will come?
Please suggest the steps which will come ,it can be done online .
what caution we have to be taken before doing this.
Regards,

Hi,
The help file itself is detailed, try to follow what it says along with checking the options specified , we cannot give in more detailed step-by-step here.
Are you trying to move single data file or multiple data files, where ever there is statement "set required options" you need to specify them.
Go with step5 if you have specified datafile path from the help link. BRtool itself is self explanatory.
If you are still not sure how to proceed, you need to download Oracle-BRtool doc.
FYI: it was not selection numbers you have to remember, but chk what are selections already exist in each screen, and proceed.
Regards......
Edited by: Sita Rr Uppalapati on Apr 14, 2009 5:49 PM

Manual segment space managed tablespaces , How tune?

I use Manual segment space managed tablespaces.
How I can tuning for high performance?
What's advantage and disavantage of Manual segment space managed tablespaces and Auto segment space managed tablespaces?
if I used more data.
I'll use Auto or manual?
Please introduce me.

ASSM deal with freelist, freelist group(RAC) storage parameters. If you use ASSM you dont need to worry about adjusting freelist and group, oracle will automatically deal with it. If you are using manual storage segment management there would no problem unless you you see heavy buffer busy waits on your tables. You may also play with freelist value for tables which have concurrent inserts and access to avoid buffer busy waits.
From oracle 9i Rel 2 onwards, you have segment level statistics to find out which segments causing more buffer busy waits and tune them accordingly. There are other meaning for buffer busy waits, check v$event_name for buffe busy waits and find out the reason code for the cause of buffer busy waits event.
Jaffar

Change SEGMENT SPACE MANAGEMENT from manual toAUTO

Hi, how can i to alter tablespace to SEGMENT SPACE MANAGEMENT AUTO ?
only with re-create the tablespace ?
regards
MDF

Hi,
Oracle says :
Your specification at tablespace creation time of your method for managing available space in segments, applies to all segments subsequently created in the tablespace. Also, your choice of method cannot be subsequently altered. Only permanent, locally managed tablespaces can specify automatic segment-space management.
Paolo

Space management oracle

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