Space Management auto in Existing tablespace

Hi,
I already have several tablespaces for which I want to use/transfer to automatic space management, is it possible if yes, then How, Thanks in advance.
khawar.

If syed khawar ekram really is asking about ASM, automatic storage management, available with 10g then I think the answer is the same: Create a new tablespace using ASM files and migrate the objects.
I find conversion of dictionary managed tablespaces to locally managed using dbms_space_admin to not be worth the effort since your only option is the auto-allocate storage method and the procedure does not rebuild the objects leaving the tablespace a hodgepod of whatever happens to be there. It is generally worth the efford to build a new tablespace and migrate the objects.
IMHO -- Mark D Powell --

Similar Messages

Conversion to segment space management auto

My production databases is 10gR2, tablespaces are created locally managed with segment space management manual.
I wanted to change the segment space management to AUTO.
What is the best way to do this keeping the downtime minimal?
Thanks
S~

A summary.
First, you cannot convert to ASSM. The only mechanism provided is to create a new tablespace with segment space management auto and then move all objects across from their existing tablespace. That is the only conversion mechanism provided or possible.
Second, you probably don't want to convert to ASSM anyway. It is designed to resolve the problem of massive contention for hot blocks on inserts -the kind of thing that will happen in a RAC. In a RAC, ASSM is extremely good news and you'd be mad NOT to use it. But if you don't have a RAC, then the chances of you needing ASSM are much less. If you find particular segments that suffer from insert contention (the symptoms are lots of buffer busy waits and ITL waits), then move those few segments that need the ASSM treatment into specially-created ASSM tablespaces. But don't go doing bulk converts of things that don't need it!
Third, if you are using OMF and ASM, then that's another situation in which ASSM makes a lot of sense: you're automating everything else anyway, so why not use the automatic 'freelists' mechanism, too?
Fourth, ASSM is about how a table knows where its next insert will take place. Extent Management Local/Uniform is all about how a tablespace allocates chunks of space to segments that need it. Completely different technologies.
Fifth, I would always use extent management auto, because do you know what are the "right" extent sizes to allocate to tables? No, I didn't think so. Oracle can work it out for you, though, with no detriment to you, your tables or your performance levels.
Sixth, back on the topic of ASSM, you might find this article useful:
http://www.dizwell.com/prod/node/541

Datafile - space management

Hi,
Which is teh best practice in creating a tablespace? We have our production db on solaris. We are in teh process of migrating teh db into a linux box.
Our tablespaces comprises of one datafile each, and these datafiles are of size mostly over 3-4 gb
Is it advisable to create tablespace with multiple datafiles( eg three datafiles of one 1gb each) so that this I/O overhead is distributed equally among teh files.
Suppose tehre are more than one datafile for a tablespace..
How does data get stored in these files? I mean does these files get filled concurrently or does the second datafile start filling up only after the first datafile runs out of space?
Pls advise..
I want to know whether i have to split the large datafiles i have for my tablespaces when i create these tablespaces in teh linux box.
Pls advise

Hi,
>>I want to know how datafiles are wriitten..like if teh 2'nd datafile starts filling only if teh 1'st datifile is filled up
No. There is no order or rule for DBWn background process to writes on data files when a tablespace there are many data files, and 2'nd datafile can be used even if 1'st is not complete filled.
Look at the example below:
SYSTEM@teste> create tablespace test
2      datafile
3      '/u01/oradata/BDRPS/test01.dbf' size 5M,
4      '/u01/oradata/BDRPS/test02.dbf' size 5M,
5      '/u01/oradata/BDRPS/test03.dbf' size 5M,
6      '/u01/oradata/BDRPS/test04.dbf' size 5M,
7      '/u01/oradata/BDRPS/test05.dbf' size 5M,
8      '/u01/oradata/BDRPS/test06.dbf' size 5M
9      extent management local segment space management auto;
Tablespace created.
SYSTEM@teste> select   FILE_NAME AS DATAFILE,
2           d.TABLESPACE_NAME AS TABLESPACE,
3           d.BYTES/1048576 as SIZE_MB,
4           ROUND(sum(nvl(e.BYTES,0))/1048576) as USED_MB,
5           (round(sum(nvl(e.BYTES,0)) / (d.BYTES), 4) * 100) AS PERC_USED,
6           ROUND((d.BYTES - nvl(sum(e.BYTES),0))/1048576) AS FREE_SPACE_MB
7 from     DBA_EXTENTS e,    DBA_DATA_FILES d
8 where    d.FILE_ID = e.FILE_ID (+) AND d.tablespace_name = 'TEST'
9 group    by FILE_NAME, d.TABLESPACE_NAME, d.FILE_ID, d.BYTES, STATUS
10 order    by d.TABLESPACE_NAME, d.FILE_ID;
DATAFILE                                 TABLESPACE                        SIZE_MB    USED_MB PERC_USED FREE_SPACE_MB
/u01/oradata/BDRPS/test01.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test02.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test03.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test04.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test05.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test06.dbf            TEST                                    5          0          0             5
6 rows selected.
SYSTEM@teste> create user scott identified by tiger default tablespace test quota unlimited on test;
User created.
SYSTEM@teste> grant connect to scott;
Grant succeeded.
SYSTEM@teste> connect scott/tiger@teste;
Conectado.
SCOTT@teste> create table emp (cod number);
Table created.
SCOTT@teste> begin
2    for i in 1..100000
3    loop
4     insert into emp values (i);
5    end loop;
6 end;
7 /
PL/SQL procedure successfully completed.
SCOTT@teste> commit;
Commit complete.
SCOTT@teste> connect system/manager@teste
SYSTEM@teste> select   FILE_NAME AS DATAFILE,
2           d.TABLESPACE_NAME AS TABLESPACE,
3           d.BYTES/1048576 as SIZE_MB,
4           ROUND(sum(nvl(e.BYTES,0))/1048576) as USED_MB,
5           (round(sum(nvl(e.BYTES,0)) / (d.BYTES), 4) * 100) AS PERC_USED,
6           ROUND((d.BYTES - nvl(sum(e.BYTES),0))/1048576) AS FREE_SPACE_MB
7 from     DBA_EXTENTS e,    DBA_DATA_FILES d
8 where    d.FILE_ID = e.FILE_ID (+) AND d.tablespace_name = 'TEST'
9 group    by FILE_NAME, d.TABLESPACE_NAME, d.FILE_ID, d.BYTES, STATUS
10 order    by d.TABLESPACE_NAME, d.FILE_ID;
DATAFILE                                 TABLESPACE                        SIZE_MB    USED_MB PERC_USED FREE_SPACE_MB
/u01/oradata/BDRPS/test01.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test02.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test03.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test04.dbf            TEST                                    5          0          0             5
/u01/oradata/BDRPS/test05.dbf TEST 5 1 20 4
/u01/oradata/BDRPS/test06.dbf TEST 5 1 20 4
6 rows selected.
SYSTEM@teste> connect scott/tiger@teste;
Connected.
SCOTT@teste> insert into emp select * from emp;
100000 rows created.
SCOTT@teste> /
200000 rows created.
SCOTT@teste> commit;
Commit complete.
SCOTT@teste> insert into emp select * from emp;
400000 rows created.
SCOTT@teste> rollback;
Rollback complete.
SCOTT@teste> connect system/manager@teste
Connected.
SYSTEM@teste> select   FILE_NAME AS DATAFILE,
2           d.TABLESPACE_NAME AS TABLESPACE,
3           d.BYTES/1048576 as SIZE_MB,
4           ROUND(sum(nvl(e.BYTES,0))/1048576) as USED_MB,
5           (round(sum(nvl(e.BYTES,0)) / (d.BYTES), 4) * 100) AS PERC_USED,
6           ROUND((d.BYTES - nvl(sum(e.BYTES),0))/1048576) AS FREE_SPACE_MB
7 from     DBA_EXTENTS e,    DBA_DATA_FILES d
8 where    d.FILE_ID = e.FILE_ID (+) AND d.tablespace_name = 'TEST'
9 group    by FILE_NAME, d.TABLESPACE_NAME, d.FILE_ID, d.BYTES, STATUS
10 order    by d.TABLESPACE_NAME, d.FILE_ID;
DATAFILE                                 TABLESPACE                        SIZE_MB    USED_MB PERC_USED FREE_SPACE_MB
/u01/oradata/BDRPS/test01.dbf TEST 5 2 40 3
/u01/oradata/BDRPS/test02.dbf TEST 5 2 40 3
/u01/oradata/BDRPS/test03.dbf TEST 5 1 20 4
/u01/oradata/BDRPS/test04.dbf TEST 5 1 20 4
/u01/oradata/BDRPS/test05.dbf TEST 5 2 40 3
/u01/oradata/BDRPS/test06.dbf TEST 5 2 40 3
6 rows selected.You can see that the data files are been writing without a specific order.
Cheers

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

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

Different between datafile autoextent and tablespace extent management auto

hi guys,
the above got me thinking.
blocks are arrange in extents. The rest is ???? //??? ... . .... ..

flaskvacuum wrote:
hi guys,
the above got me thinking.
blocks are arrange in extents. The rest is ???? //??? ... . .... .. Datafile autoextend (its not datafile auto extent) - It will increase datafile size when all space in datafile is occupied and all its extents are used. So when objects needs to grow, oracle will increase the size of datafile (if autoextend is ON) and allocate extents to objects.
Also see http://docs.oracle.com/cd/B28359_01/server.111/b28310/dfiles003.htm
Tablespace extent management auto - Local managed tablespace will keep the track of extents in Bitmaps. Now creating this type of tablespace you can specify AUTOALLOCATE clause or the UNIFORM clause, AUTOALLOCATE will assign new extents to obejcts of size determine by oracle internally. UNIFORM if specified, oracle will assign uniform size extents to objects. Lets say you have specified 1M of Uniform size, then oracle will assign 1M of new extents to objects, all assigned extents will have same size i.e 1M. But its not the case with Autoallocate.
Autoallocate will determine whats the best extent size which he needs to allocate to segement. Its internal mechanism
http://docs.oracle.com/cd/B19306_01/server.102/b14231/tspaces.htm

How to identify the SEGMENT SPACE MANAGEMENT is AUTO turned ON

how to identify the SEGMENT SPACE MANAGEMENT is AUTO turned ON for a particular tablespace.

Hello,
Try:
SELECT tablespace_name, file_name, autoextensible
FROM DBA_DATA_FILES
ORDER BY tablespace_name, file_name;Oops, wrong answer, try:
SELECT tablespace_name, segment_space_management
FROM dba_tablespaces
order by tablespace_name;

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

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

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 ?

Fragmented free space in empty LMT ASSM tablespace?

select count(*) from dba_extents where file_id=127;COUNT(*)
0
select count(*) from dba_free_space where file_id=127;COUNT(*)
2
select block_id, blocks from dba_free_space where file_id=127;
BLOCK_ID     BLOCKS
       128     507904
    508032     139616
select extent_management, segment_space_management, allocation_type
from dba_tablespaces
where tablespace_name=(select tablespace_name from dba_data_files where file_id=127);EXTENT_MANAGEMENT     SEGMENT_SPACE_MANAGEMENT     ALLOCATION_TYPE
LOCAL     AUTO     SYSTEM
alter tablespace ... coalesce;
select count(*) from dba_free_space where file_id=127;COUNT(*)
2
select version from product_component_version where product like 'Oracle%';VERSION
11.2.0.2.0
How is that possible?

user5066799 wrote:
Thanks Jonathan, but, sorry - have not got - what do you mean? Do you mean that space management blocks occupy first 128 blocks of datafile or do they occupy blocks after last free extent block? The only management blocks I expect to find are these first 128 blocks (1M) which as I understand are datafile header (was 64K in earlier versions, but in 11.2 is 1M, with 8K results in 128 blocks).
Or do you mean the fact of using autoallocate extent size influences this matter? Should we consider "autoallocate start size" of 64K in relation to something?Your interpretation of what I was saying is correct - but I got the scale wrong, there's a different explanation of what you're seeing.
If you dump the first few blocks of the file, in your case using something like:
alter system dump datafile 129 block min 2 block max 6;you will see that block 2 will be the "file space header block" and the next blocks will be file space bitmap blocks.
Each file space bitmap block (in an 8KB block) loses a couple of hundred bytes to block headers and other control details, then has one bit for each 64KB of the data file, where the 64KB unit is dictated by the autoallocate option
Sample dump:
buffer tsn: 14 rdba: 0x01c00002 (7/2)
scn: 0x0b86.40279c3f seq: 0x01 flg: 0x04 tail: 0x9c3f1d01
frmt: 0x02 chkval: 0x3100 type: 0x1d=KTFB Bitmapped File Space Header
File Space Header Block:
Header Control:
RelFno: 7, Unit: 8, Size: 655360, Flag: 1
AutoExtend: NO, Increment: 0, MaxSize: 0
Initial Area: 126, Tail: 655359, First: 0, Free: 81904
buffer tsn: 14 rdba: 0x01c00003 (7/3)
scn: 0x0b86.40279b45 seq: 0x01 flg: 0x04 tail: 0x9b451e01
frmt: 0x02 chkval: 0x0afb type: 0x1e=KTFB Bitmapped File Space Bitmap
File Space Bitmap Block:
BitMap Control:
RelFno: 7, BeginBlock: 128, Flag: 0, First: 0, Free: 63488
buffer tsn: 14 rdba: 0x01c00004 (7/4)
scn: 0x0b86.40279b47 seq: 0x01 flg: 0x04 tail: 0x9b471e01
frmt: 0x02 chkval: 0xcafb type: 0x1e=KTFB Bitmapped File Space Bitmap
File Space Bitmap Block:
BitMap Control:
RelFno: 7, BeginBlock: 508032, Flag: 0, First: 0, Free: 63488 Note particularly the "Free: 63488" - which is bits, each bit represents 8 blocks for a total of 507904. Allowing for the first 128 blocks in the file this is why the map in block 7/4 has a BeginBlock of 508032.
A single extent in dba_free_extents is, apparently, not allowed to cross a space management block.
Regards
Jonathan Lewis
P.S. Since there are 126 available file space bitmap blocks, and 507904 blocks allowed per bitmap block, then when the file hits 63,995,904 blocks (488.25 GB) Oracle will have to add a secondary space management area. (At least, that's if you grow the file to that size; if you pre-create the tablespace at that something above that size then perhaps Oracle will allocate 2M of file header.)
P.P.S Here's a quote from my errata pages for Practical Oracle 8i: "Allowing for a little overhead, a single 8K block can hold information about 63,488 extents,..." so not a lot has changed in the interim, apart from the fact that the header is now 1MB rather than 64KB - possibly to cater for bigfile tablespaces, possibly to help ASM and Exadata align their extents and AUs.
Edited by: Jonathan Lewis on Dec 7, 2012 6:30 PM

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.

Manual segment space management / want to shrink through segment advisor

I am trying to free space from table space , but i can't check the manual segment space manageme tablespaces, only auto segment space management allow me to do so. How i can do that?
any suggestions.

sybrand_b wrote:
Confusion can best be resolved by referring to the official documentation (as opposed to cluttering up this forum full of doc questions with further doc questions).
Is there any particular reason (your boss beats you up when he sees you reading documentation) why you can't be bothered to visit http://tahiti.oracle.com, or do you -mistakingly- think this is an online chatroom, instead of an offline forum?
Sybrand Bakker
Senior Oracle DBAwhat kind of an answer is that? I mean, what is the points of books if docs were everything one ever needed? I have read something in a book that confuses me, and I disagree with, but maybe my understanding is wrong, so that is why I am come here to ask others for their opinion. What is wrong with that?

Difference between extent management and segment space management

Hello,
Could you tell me the difference between extent management and segment space management interms of datablocks?

After 10g, default tablespace is locally managed and with this creation, your segment's spaces are managed "automatically".
Automatic segment space management is onlyt avaliable to locally managed tablespaces.
The logic of the automatic segment space management is;
For instance, we have a rectangle cube which is totally empty (1 extent - 8 segments - 64 block in default). If we enter a new data to our table, data is stored inside this cube with it's information. (default 8k). If our data must be splitted, check row chaining for further information.
At this point, oracle decides which block is filled with the entered data. It automatically fills the emty blocks. You can use this only if your tablespace is locally managed and your segment space managemet is auto.
On the other hand,
If we create dictionary managed tablespace,
Data is stored in "dictionary" (tables in SYS schema). This is a bit slower than locally managed tablespaces. So filling the extents, segments and blocks will be slow too. You need to specify the PCTUSED, FREELISTS, FREELISTS GROUPS for the storage of the data. If segment space managent is auto, you don't need to define those values.
In summary, locally managed tablespaces with automatic segment space management is Oracle's maybe the most important feature. I am not using dictionary managed tablespaces and i advice don't use it either. In the end, this is an upgrade of using segment spaces much more faster, easier and reliable, trustable.
PS: You will need to check "High Water Mark" for automatic segment space management.

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

Space Management auto in Existing tablespace

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