Multiple Bolcksize (Tablespace & Buffer)

Hi,
I recently created a test instance with different block size (i.e., 8k from 4k), and after some application performance testing, could note that 2 systems which were pretty slow on production (i.e. around 30 seconds per transaction), went super fast on the test database (2-3 seconds per transaction), without actually tuning those 2 systems. This is remarkable. Database Version is 9.2.0.8.
Unfortunately, the production box won't allow me to migrate from 4k to 8k because of resource constraints. But i could use the multi block size feature to determine the objects (tables, indexes) with avg_row_len > 4 and move them to new tablespace.
I read through the article "Proof that large index blocksizes reduce I/O" at http://www.dba-oracle.com/oracle_tips_blocksizes-.htm
My query here is, as per the article, if I just move the indexes to a nK size tablespace, do i need to configure the db_nk_cache_size for the indexes to be loaded, or is it that they could use default 4k db_cache_size in my production box? Also, if there are any limitations, or precautions that I need to take care of before actually working on Production Box?
Any experiences and suggestions are msot-welcome.
Thanks & Best Regards,
Zaffer Khan

Z.K. wrote:
In my case, I created a test database with 4K block size before this 8k excercise, which is same blocksize as production box, but didn't see major performance gains due to rebuilds, in the 2 systems.
Good, that helps to eliminate (or at least down-grade) some of the possible causes - and probably makes it much easier to isolate and compare the traces for individual transactions.
Did you create the 4KB copy by copying files, or was that also a new database with an import from the old ?
Did you make any changes in the parameter file when you created the 8KB database ?
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
"Science is more than a body of knowledge; it is a way of thinking"
Carl Sagan
To post code, statspack/AWR report, execution plans or trace files, start and end the section with the tag {noformat}{noformat} (lowercase, curly brackets, no spaces) so that the text appears in fixed format.

Similar Messages

Size of a specific table on disk? Queries over multiple (2) tablespaces?

I am looking for a way to find out (for Oracle 9.2.0.1.0).
How much space does each or a specific table require on disk?
(whether with indices or without is the other question).
And how much "payload" data is in each or a specific table?
Another question - of my team leader - is:
Is it possible to make queries over multiple (2) tablespaces?
I assume - no - am I right?
Thank you for precise answers as well as links to other threads in this forum (where I did not find it until now),
and chapters in online documentation - or other sources.
PS: I know SQL, PL/SQL a bit.
We have Oracle Enterprise Manager console and SQL*Plus console.

>
The table size can not be found in bytes precisely, but in number of blocks of a certain size allocated for this table (index etc.).
select segment_type,segment_name, Sum(Bytes)/1024 as kB from DBA_EXTENTS
where tablespace_name = 'xyz' group by segment_type,segment_name;
There are more blocks allocated for a table than space is needed by the current data amount.
I guess, that this table was once bigger and has been emptied a bit.
>
A table grows in extents that get filled then with new rows. The columns
blocks and bytes of user_tables get populated from dba_stats.
In below example, the table rows have filled up to MB_TABLE the extents:
SQL> select table_name,blocks*8/1024 as mb from user_tables order by 1;
TABLE_NAME                   MB_TABLE
CUSTOMERS            11.6015625
SALES                 278.96875
SQL> select segment_name,bytes/1024/1024 as mb from user_segments order by 1;
SEGMENT_NAME                 MB_SEGMENT
CUSTOMERS                    12
SALES                       285If you later on delete again from the tables, that does not deallocate extents nor remove the high water mark unless you reorganize the table:
SQL> select count(*) from customers;
COUNT(*)
     55500
SQL> delete from customers where rownum<25000;
24999 rows deleted.
SQL> commit;
Commit complete.
SQL> select segment_name,bytes/1024/1024 as mb from user_segments order by 1;
SEGMENT_NAME                 MB
CUSTOMERS                    12
SALES                       285
SQL> select table_name,blocks*8/1024 as mb from user_tables order by 1;
TABLE_NAME                   MB
CUSTOMERS            11.6015625
SALES                 278.96875
SQL> exec dbms_stats.gather_table_stats('ADAM','CUSTOMERS')
PL/SQL procedure successfully completed.
SQL> select table_name,blocks*8/1024 as mb from user_tables order by 1;
TABLE_NAME                   MB
CUSTOMERS            11.6015625
SALES                 278.96875
SQL> alter table customers enable row movement;
Table altered.
SQL> alter table customers shrink space;
Table altered.
SQL> exec dbms_stats.gather_table_stats('ADAM','CUSTOMERS')
PL/SQL procedure successfully completed.
SQL> select segment_name,bytes/1024/1024 as mb from user_segments order by 1;
SEGMENT_NAME                 MB
CUSTOMERS                6.4375
SALES                       285
SQL> select table_name,blocks*8/1024 as mb from user_tables order by 1;
TABLE_NAME                   MB
CUSTOMERS             6.2265625
SALES                 278.96875Kind regards
Uwe
http://uhesse.wordpress.com

Multiple TEMP tablespaces

RDBMS version:11.2, 10.2
We usually create only one temporary tablespace (TEMP) for a database. But, our application team is asking us to create two more dedicated Temporary tablespaces for 2 of its DB schemas which have high activity and assign it as the default temporary tablespaces for it.
Are there any advantages in creating separate TEMP tablespaces for highly active schemas ? Can't I just have one tablespace and increase the size of this TEMP tablespace instead ?

SM_308 wrote:
RDBMS version:11.2, 10.2
We usually create only one temporary tablespace (TEMP) for a database. But, our application team is asking us to create two more dedicated Temporary tablespaces for 2 of its DB schemas which have high activity and assign it as the default temporary tablespaces for it.
Are there any advantages in creating separate TEMP tablespaces for highly active schemas ? Can't I just have one tablespace and increase the size of this TEMP tablespace instead ?I would recommend single larger TEMP tablespace

Multiple file tablespace

Can a Table extend to a different datafile once the first file is to capacity?

There is space. This table is in sjs02.dbf and would need to extend into sjs01.dbf. ???
FILE_NAME TBS SIZE USED
C:\ORACLE\ORA92\DATABASE\RBS01.DBF RBS 925,892,608 445,120,512 48%
C:\ORACLE\ORA92\DATABASE\SJS01.DBF SJS 1,887,436,800 818,413,568 43%
C:\ORACLE\ORA92\DATABASE\SJS02.DBF SJS 1,572,864,000 1,410,727,936 90%
C:\ORACLE\ORA92\DATABASE\TEMP01.DBF TEMP 235,929,600 1,048,576 00%
C:\ORACLE\ORA92\DATABASE\USERS01.DBF USERS 502,005,760 327,417,856 65%
C:\ORACLE\ORA92\DATABASE\SYSTEM01.DBF SYSTEM 367,001,600 258,547,712 70%

Is there so call "dedicated" UNDO tablespace in Oracle 9i and higher?

Since one of our applicaions needs to process large amounts of data, we have been using a dedicated rollback segment in order to avoid the "snapshot too old" problem.
Recently our DB upgraded to Oracle 9i and DBA asked us to use "undo" tablespace.
Based the Oracle 9i Doc., it only allows to select ONE undo tablespace at a time.
If so, DBA has to make the only UNDO as large as our Cash large transactions
need(adjust the UNDO_RENTION), which inevitably waste lots of space.
Does Oracle 9i allow to have one dedicated UNDO tablespace for large transactions while another one for regular transactions just like we use the old rollback segments.
Thanks in advance

Why have multiple UNDO tablespaces? You can only use one at a time, and when the other one is not being used, it still consumes storage space.
Spend a little time determining how much undo you need and size undo tablespace and undo retention around those values and you should be able to resolve the problems you are experiencing now.
http://download-east.oracle.com/docs/cd/B10501_01/server.920/a96521/undo.htm#9505

Tablespace Groups

Hi,
Going throug the documentations, I found a few references to tablespace groups, specifically in reference to temporary tablespaces. I found it in the Administrator's Guide and the Concepts manuals. But I could not find any explanations as to what a tablespace group is or how to create it. Could one of you please clarify the same for me or point me to the documentation/white papers where I could find an explanation ?
Thanks in advance,
Regards,
Sriraman

A tablespace group enables a user to consume temporary space from multiple tablespaces.
A tablespace group has the following characteristics:
It contains at least one tablespace.
There is no explicit limit on the maximum number of tablespaces that are contained in a group.
It shares the namespace of tablespaces, so its name cannot be the same as any tablespace.
You can specify a tablespace group name wherever a tablespace name would appear when you assign a default temporary tablespace for the database or a temporary tablespace for a user.
You do not explicitly create a tablespace group. Rather, it is created implicitly when you assign the first temporary tablespace to the group. The group is deleted when the last temporary tablespace it contains is removed from it.
Using a tablespace group, rather than a single temporary tablespace, can alleviate problems caused where one tablespace is inadequate to hold the results of a sort, particularly on a table that has many partitions. A tablespace group enables parallel execution servers in a single parallel operation to use multiple temporary tablespaces.
Data Dictionary Object dba_tablespace_groups
Group Creation
With Create Tablespace
CREATE TEMPORARY TABLESPACE batchtemp
TEMPFILE '/u02/oradata/temp04.dbf'
SIZE 250M
TABLESPACE GROUP temp_grp;
With Alter Tablespace ALTER TABLESPACE <tablespace_name>
TABLESPACE GROUP <group_name>;
ALTER TABLESPACE tools TABLESPACE GROUP apps_grp;
Remove A Group Member
Tablespace Removal ALTER TABLESPACE <tablespace_name> TABLESPACE GROUP '';
ALTER TABLESPACE batchtemp TABLESPACE GROUP '';
Default Temporary Tablespace Assignment
Make a group the default group ALTER DATABASE <tablespace_name>
DEFAULT TEMPORARY TABLESPACE <group_name>;
ALTER DATABASE orabase
DEFAULT TEMPORARY TABLESPACE app_grp;

System tablespace Vs User Tablespace

I'm running oracle 8i at Win2000 Server.
I have a database which have two SYSTEM tablepspaces and One User tablespace. Both SYSTEM Tablepspaces are near to FULL. Right now , The database performance is very poor. I can't understand why my SYSTEM tablespaces are growing fastly instead of User Tablepspace.

You cannot have multiple SYSTEM tablespaces... Do you mean that you have multiple datafiles associated with your SYSTEM tablespace?
Unless you assign users a default tablespace, objects that they create without specifying a tablespace will be placed in the SYSTEM tablespace, which is a bad thing. You probably have user objects in your SYSTEM tablespace.
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

10G: TEMPORARY TABLESPACES GROUP

제품 : ORACLE SERVER
작성날짜 : 2004-05-25
10G: TEMPORARY TABLESPACES GROUP
==================================
PURPOSE
이 문서에서는 10g New Feature 인 Temporary tablespace 의 group 에 대해 알아 보도록 한다.
Explanation
10g 에서는 temporary tablespaces 에 대해 group 을 지정하여 생성할 수 있고
consumer group 을 지정하여 resource manager 와 함께 적용하여 사용이 가능하다.
다음은 Temporary tablespace group 지정을 위한 기본적이 사항이다.
1. 하나의 temporary tablespace group 은 적어도 하나의 tablespace 가 존재해야 하고
maximum number tablespace 에 대한 limit 은 정해져 있지 않다.
2. Ttemporary tablespace 와 group name 을 동일하게 지정할 수 없다.
3. Temporary tablespace group 은
     1) 한 group 에서 다른 group 으로 move 가 가능하고
     2) Group 내에서 삭제 될 수 있으며
     3) 추가적으로 add 가 가능하다.
4. Temporary tablespace group 사용으로 인해
     1) Sort 결과를 유지하여 space 낭비를 막을 수 있고
     2) 동시에 여러개의 session connect 시에도 서로 다른 temporary tablespaces 를 사용함으로써
     temporary tablespaces 의 사용을 분산 시킬 수 있다.
     3) Parallel operation 시에도 multiple temporary tablespaces 사용이 가능하다.
Example
1. GROUP1 을 지정하고 GROUP1 에 속하는 temporary tablespace LMTEMP 1 를 생성한다.
이 때 GROUP 1 을 따로 생성할 필요 없고 temporary tablespace 생성시에 지정하도록 한다.
SQL> create temporary tablespace LMTEMP 1
tempfile 'D:\ORACLE10\ORCL\temp1_01.dbf' size 50M
tablespace group GROUP1;
SQL> select * from dba_tablespace_groups;
GROUP_NAME TABLESPACE_NAME
GROUP1 LMTEMP1
2. LMTEMP2 를 GROUP1 에 새로 추가한다.
SQL> create temporary tablespace lmtemp2
tempfile 'D:\ORACLE10\ORCL\temp1_02.dbf' size 2M
tablespace group group1;
Tablespace created.
SQL> select * from dba_tablespace_groups;
GROUP_NAME TABLESPACE_NAME
GROUP1 LMTEMP1
GROUP1 LMTEMP2
3. 기존에 존재하는 LMTEMP1 를 GROUP2 로 move 한다.
SQL> alter tablespace LMTEMP1 tablespace group GROUP2 ;
Tablespace altered.
SQL> select * from dba_tablespace_groups;
GROUP_NAME TABLESPACE_NAME
GROUP2 LMTEMP1
GROUP1 LMTEMP2
4. LMTEMP1 이 속해 있던 GROUP2 에서 LMTEMP1 를 제외 시키고 다시 포함시킬 수 있다.
SQL> alter tablespace LMTEMP1 tablespace group '';
Tablespace altered.
SQL> select * from dba_tablespace_groups;
GROUP_NAME TABLESPACE_NAME
GROUP1 LMTEMP2
SQL> select tablespace_name from dba_tablespaces where contents='TEMPORARY';
TABLESPACE_NAME
TEMP
LMTEMP1
LMTEMP2
SQL> alter tablespace LMTEMP1 tablespace group GROUP1;
Tablespace altered.
5. Temporary tablespace 와 group name 을 동일하게 지정할 경우 ORA-10918 에러가 발생한다.
즉, temporary tablespace 와 group name 을 동일하게 지정이 불가능하다.
SQL> create temporary tablespace lmtemp5
tempfile 'D:\ORACLE10\ORCL\temp1_05.dbf' size 50M
tablespace group lmtemp5;
create temporary tablespace lmtemp5
ERROR at line 1:
ORA-10918: TABLESPACE GROUP name cannot be the same as tablespace name
6. 존재하던 모든 temporary tablespaces 를 drop 하게 되면 group 은 자동으로 remove 된다.
SQL> create temporary tablespace LMTEMP3
tempfile 'D:\ORACLE10\ORCL\temp1_03.dbf' size 2M
tablespace group GROUP2;
Tablespace created.
SQL> create temporary tablespace LMTEMP4
tempfile 'D:\ORACLE10\ORCL\temp1_04.dbf' size 2M
tablespace group GROUP2;
Tablespace created.
SQL> select * from dba_tablespace_groups;
GROUP_NAME TABLESPACE_NAME
GROUP1 LMTEMP1
GROUP1 LMTEMP2
GROUP2 LMTEMP3
GROUP2 LMTEMP4
SQL> drop tablespace lmtemp3 including contents and datafiles;
Tablespace dropped.
SQL> drop tablespace lmtemp4 including contents and datafiles;
Tablespace dropped.
SQL> select * from dba_tablespace_groups;
GROUP_NAME TABLESPACE_NAME
GROUP1 LMTEMP1
GROUP1 LMTEMP2
7. Group 에 user 사용이 가능하도록 지정할 수 있다.
SQL> alter user scott temporary tablespace GROUP1;
User altered.
8. Temporary tablespace group 을 database level 의 default temporary tablespace 로도 지정할 수 있다.
SQL> alter database <db_name> default temporary tablespace GROUP1;
Database altered.
만약, temporary tablespaces 가 default database temporary tablespace group 에 속해 있는경우
drop 시 ORA-10921 에러가 발생하게 된다. 즉, default temporary tablespace group 에 속해 있는 경우
drop 할 수 없다.
SQL> drop tablespace LMTEMP2 including contents and datafiles;
drop tablespace lmtemp2 including contents and datafiles
ERROR at line 1:
ORA-10921: Cannot drop tablespace belonging to default temporary tablespace
group
Reference Documents
<NOTE. 245645.1>

Hi,
Take a look in
1 - DBA_TEMP_FILES :http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96536/ch2398.htm
2 - V$TEMPFILE: http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96536/ch3225.htm
Cheers,
Marcello M.

TEMP Tablespace Groups

In Datawarehouse environment, Database verion 10gR2:
Created two temp tablespaces TEMP1 and TEMP2 with 10GB each in a temp tablespace group(TEMP_GROUP) and assigned the TEMP_GROUP as default temporary tablespace to user "BATCH", expecting the batch user can use 20GB of temp tablespace.
When a process needs a temp tablespace of more than 10GB, the process fails with an error unable to extend temp tablespace. It is not utilizing the other 10GB TEMP tablespace.
When I assign a dedicated TEMP tablespace TEMP3 with 15GB as the default temp tablespace, the process succeeds.
It looks like when a session starts it assigns one TEMP tablespace(from group), if that fills up it is not taking advantage of the other TEMP tablespace in the group, which makes me think that Groups are not helping here.
Is there an other way around to utilize multiple temp tablespaces for a single user.
Can we expect an improvement of this feature in the future releases or is that not a possible scenario?

-- Using a tablespace group, rather than a single temporary tablespace, can alleviate problems caused where one tablespace is inadequate to hold the results of a sort, particularly on a table that has many partitions. A tablespace group enables parallel execution servers in a single parallel operation to use multiple temporary tablespaces.
CREATE TEMPORARY TABLESPACE TEMP2 TEMPFILE '/u10/oracle/oradata/dbt1/datafile/temp02.dbf'
SIZE 20M
TABLESPACE GROUP tempgroup1;
CREATE TEMPORARY TABLESPACE TEMP3 TEMPFILE '/u10/oracle/oradata/dbt1/datafile/temp03.dbf'
SIZE 20M
TABLESPACE GROUP tempgroup2;
ALTER TABLESPACE temp TABLESPACE GROUP tempgroup1;
select * from v$tempfile ;
select * from dba_tablespace_groups ;
alter user ABCD temporary tablespace tempgroup1 ;
-- Verify that temp group is assigned to user
select * from dba_users where username='ABCD' ;
After you assign the group to the user abcd then retry your operation as abcd user.
This time it will use both the temporary tablespaces for sort operations.
Thanks
GC

1D Array for Data to buffer

I have a force plate that sends out forces in the x,y,z and i need to be able to index them into a 1D array for a buffer. I think i have the ground work of the program laid out but im not sure where to go from here. See attached program. Thanks for any possible help.
Attachments:
Buffer.vi ‏20 KB

Your VI will run forever because you have a False constant wired to the stop terminal of the loop.
Why do you have a while loop in there anyway?
You don't have any element going into your replace array subset. So you have a broken arrow.
I don't understand the meaning of your buffer full boolean. It really isn't telling whether your buffer is full or not. It doesn't even track how many times you've replaced various elements in the array. It just checks whether the value you used for index is a multiple of your buffer size. Let's say yor buffer size is 10. If you use an index 9, the remainder of 9 mod 10 is 9, it's not equal to 0, so the boolean is false. Okay.
Now if your index is 10, 10 mod 10 is 0, it's equal to 0, so the boolean is true. Okay.
Now if your index is 11 (obviously bigger than 10) 11 mod 10 is 1. It's not equal to 0, so the boolean is back to false. But is seems like you really intend for it to be true.
You aren't really ever checking if your array is "full". You are just comparing your entered index to your "buffer size" input, which may not actually have anything to do with the size of the array.

Disable Multiple temp space in OEM 12C

Hi,
I've centralized OEM 12C for monitoring. I want to disable the monitoring of multiple temp space.
i've disabled default temporary tablespace and undo tablespace of the test database in OEM 12c. But it is not covering for multiple temporary tablespaces.
Is it possible for disable multiple temp space? any other way?
Thanks in advance.
Thanks,
Robin

Robin,
You can do a "Create Like" on the DISABLE TABLESPACE USED (%) ALERTS FOR UNDO AND TEMP TABLESPACES job and modify the sql listed below, which is used for the cursor, to something that will work for your temporary tablespaces.
select tablespace_name from dba_tablespaces where CONTENTS IN ('UNDO', 'TEMPORARY');
Regards,
- Loc

Qeustion regarding temp tablespace group

Hi All,
I am new to this concept. I've been reading about it but there is something I am not sure to understand.
If I have a temp tablespace group using tablespace temp1 and temp2 and a user submit a large query, will the query use both temp1 and temp2 or just 1 of them?
Group Name: temp
Tablespace: temp01 (1 datafile temp01.dbf)
Tablespace: temp02 (1 datafile temp02.dbf)
Thank you!

1. A single workarea execution can't use space from more a single tablespace even when the user is assigned a temporary tablespace group. Or in other words: A single workarea execution can only allocate a single temporary segment, and segments in general can't span multiple tablespaces in Oracle, i.e. they must fit into a single tablespace.
2. Even multiple workareas for a single session can't use space from the multiple temporary tablespaces available. So this looks like a session attribute, i.e. assigned to the session, and all workareas of that session will use the single temporary tablespace assigned (taken from the group)
3. Multiple sessions of the same user can be assigned to different temporary tablespaces taken from the group.
4. Parallel execution slave sessions can do the same, they can be assigned to different temporary tablespaces taken from the group.
So in order to leverage the power of temporary tablespace groups you need either multiple sessions running serial SQL or the parallel execution option.
Source:http://oracle-randolf.blogspot.in/2009/06/temporary-tablespace-groups.html
Regards
Girish Sharma

BUFFER IS PINNED COUNT

Hello !
Could I ask You to explain about BUFFER IS PINNED COUNT please ?
http://dbaspot.com/oracle-server/156378-definition-buffer-pinned-count.html
http://www.freelists.org/archives/or.../msg00697.html
"Buffer is pinned count: -
Oracle has previously pinned a buffer, and
not released it immediately. A pin may be
held for the duration of a database call.
Oracle can revisit the buffer by traversing
the pin without acquiring the latch, because
the presence of the pin ensures that no other
session could have acquired that buffer in a
conflicting fashion."
Can You explain in other words please ?
Is it possible visit without latch ?
Thanks and regards,
Pavel
Edited by: Pavel on Mar 1, 2012 11:24 PM

Difference between "buffer is not pinned count" and "BUFFER IS PINNED COUNT"
buffer is not pinned count means the number of times the buffer was free when visited whereas "BUFFER IS PINNED COUNT" means the number of times the buffer was pinned when visited.
Pavel you said During intensive ""Select"-operations (scatered or sequential read ???) we should see higth value of buffer is not pinned count ? "
Why do you feel that, if you are trying to reading multiple blocks from buffer cache you may still found other reasons too for waiting the buffers which you want to read like session waits on the buffer hash chain latch.. or perhaps buffer busy waits and so on...The buffers whch you are trying to access may offcourse be pinned by other processes, so what exact answer you want, please be specific.
For your basic concept Pavel, cache buffers chains latches are taken when a process wants to walk through a cache buffer hash chain, looking if the block with required DBA (data block address) is in buffer cache. If the block happens to be in cache, then in most cases it has to be pinned first before use and unpinned after use, to make sure no-one else can perform an incompatible operation on that block at the same time. The modification of pin structures (pinning/unpinning) is also protected by CBC latches. Rest Aman sir and Fran has explained you well already
Regards
Karan

Oracle 10G New Feature........Part 1

Dear all,
from last couple of days i was very busy with my oracle 10g box,so i think this is right time to
share some intresting feature on 10g and some internal stuff with all of you.
Have a look :-
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Oracle 10g Memory and Storage Feature.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1.Automatic Memory Management.
2.Online Segment Shrink
3.Redolog Advisor, checkpointing
4.Multiple Temporary tablespace.
5.Automatic Workload Repository
6.Active Session History
7.Misc
a)Rename Tablespace
b)Bigfile tablespace
c)flushing buffer cache
8.ORACLE INTERNAL
a)undocumented parameter (_log_blocks_during_backup)
b)X$ view (x$messages view)
c)Internal Structure of Controlfile
1.Automatic memory management
================================
This feature reduce the overhead of oracle DBA.previously mostly time we need to set diff oracle SGA parameter for
better performance with the help of own experience,advice views and by monitoring the behaviour
of oracle database.
this was just time consuming activity.........
Now this feature makes easy life for oracle DBA.
Just set SGA_TARGET parameter and it automatically allocate memory to different SGA parameter.
it focus on DB_CACHE_SIZE
SHARED_POOL_SIZE
LARGE_POOL
JAVA_POOL
and automatically set it as
__db_cache_size
__shared_pool_size
__large_pool_size
__java_pool_size
check it in alert_log
MMAN(memory manager) process is new in 10g and this is responsible for sga tuning task.
it automatically increase and decrease the SGA parameters value as per the requirement.
Benefit:- Maximum utlization of available SGA memory.
2.Online Segment Shrink.
==========================
hmmmmm again a new feature by oracle to reduce the downtime.Now oracle mainly focus on availablity
thats why its always try to reduce the downtime by intrducing new feature.
in previous version ,reducing High water mark of table was possible by
Exp/imp
or
alter table move....cmd. but on these method tables was not available for normal use for long hrs if it has more data.
but in 10g with just few command we can reduce the HWmark of table.
this feature is available for ASSM tablespaces.
1.alter table emp enable row movement.
2.alter table emp shrink space.
the second cmd have two phases
first phase is to compact the segment and in this phase DML operations are allowed.
second phase(shrink phase)oracle shrink the HWM of table, DML operation will be blocked at that time for short duration.
So if want to shrink the HWM of table then we should use it with two diff command
first compact the segment and then shrink it on non-peak hrs.
alter table emp shrink space compact. (This cmd doesn't block the DML operation.)
and alter table emp shrink space. (This cmd should be on non-peak hrs.)
Benefit:- better full table scan.
3.Redolog Advisor and checkpointing
================================================================
now oracle will suggest the size of redo log file by V$INSTANCE_RECOVERY
SELECT OPTIMAL_LOGFILE_SIZE
FROM V$INSTANCE_RECOVERY
this value is influence with the value of FAST_START_MTTR_TARGET .
Checkpointing
Automatic checkpointing will be enable after setting FAST_START_MTTR_TARGET to non-zero value.
4.Multiple Temporary tablespace.
==================================
Now we can manage multiple temp tablespace under one group.
we can create a tablespace group implicitly when we include the TABLESPACE GROUP clause in the CREATE TEMPORARY TABLESPACE or ALTER TABLESPACE statement and the specified tablespace group does not currently exist.
For example, if group1 is not exists,then the following statements create this groups with new tablespace
CREATE TEMPORARY TABLESPACE temp1 TEMPFILE '/u02/oracle/data/temp01.dbf'
SIZE 50M
TABLESPACE GROUP group1;
--Add Existing temp tablespace into group by
alter tablespace temp2 tablespace group group1.
--we can also assign the temp tablespace group on database level as default temp tablespace.
ALTER DATABASE <db name> DEFAULT TEMPORARY TABLESPACE group1;
benefit:- Better I/O
One sql can use more then one temp tablespace
5.AWR(Automatic Workload Repository):-
================================== AWR is built in Repository and Central point of Oracle 10g.Oracle self managing activities
is fully dependent on AWR.by default after 1 hr, oracle capure all database uses information and store in AWR with the help of
MMON process.we called it Memory monitor process.and all these information are kept upto 7 days(default) and after that it automatically purge.
we can generate a AWR report by
SQL> @?/rdbms/admin/awrrpt
Just like statspack report but its a advance and diff version of statspack,it provide more information of Database as well as OS.
it show report in Html and Text format.
we can also take manually snapshot for AWR by
BEGIN
DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT ();
END;
**The STATISTICS_LEVEL initialization parameter must be set to the TYPICAL or ALL to enable the Automatic Workload Repository.
[oracle@RMSORA1 oracle]$ sqlplus / as sysdba
SQL*Plus: Release 10.1.0.2.0 - Production on Fri Mar 17 10:37:22 2006
Copyright (c) 1982, 2004, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> @?/rdbms/admin/awrrpt
Current Instance
~~~~~~~~~~~~~~~~
DB Id DB Name Inst Num Instance
4174002554 RMSORA 1 rmsora
Specify the Report Type
~~~~~~~~~~~~~~~~~~~~~~~
Would you like an HTML report, or a plain text report?
Enter 'html' for an HTML report, or 'text' for plain text
Defaults to 'html'
Enter value for report_type: text
Type Specified: text
Instances in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DB Id Inst Num DB Name Instance Host
* 4174002554 1 RMSORA rmsora RMSORA1
Using 4174002554 for database Id
Using 1 for instance number
Specify the number of days of snapshots to choose from
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Entering the number of days (n) will result in the most recent
(n) days of snapshots being listed. Pressing <return> without
specifying a number lists all completed snapshots.
Listing the last 3 days of Completed Snapshots
Snap
Instance DB Name Snap Id Snap Started Level
rmsora RMSORA 16186 16 Mar 2006 17:33 1
16187 16 Mar 2006 18:00 1
16206 17 Mar 2006 03:30 1
16207 17 Mar 2006 04:00 1
16208 17 Mar 2006 04:30 1
16209 17 Mar 2006 05:00 1
16210 17 Mar 2006 05:31 1
16211 17 Mar 2006 06:00 1
16212 17 Mar 2006 06:30 1
16213 17 Mar 2006 07:00 1
16214 17 Mar 2006 07:30 1
16215 17 Mar 2006 08:01 1
16216 17 Mar 2006 08:30 1
16217 17 Mar 2006 09:00 1
Specify the Begin and End Snapshot Ids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Enter value for begin_snap: 16216
Begin Snapshot Id specified: 16216
Enter value for end_snap: 16217
End Snapshot Id specified: 16217
Specify the Report Name
~~~~~~~~~~~~~~~~~~~~~~~
The default report file name is awrrpt_1_16216_16217.txt. To use this name,
press <return> to continue, otherwise enter an alternative.
Benefit:- Now DBA have more free time to play games.....................:-)
Advance version of statspack
more DB and OS information with self managing capabilty
New Automatic alert and database advisor with the help of AWR.
6.Active Session History:-
==========================
V$active_session_history is view that contain the recent session history.
the memory for ASH is comes from SGA and it can't more then 5% of Shared pool.
So we can get latest and active session report from v$active_session_history view and also get histortical data of
of session from DBA_HIST_ACTIVE_SESS_HISTORY.
v$active_session_history include some imp column like:-
~SQL identifier of SQL statement
~Object number, file number, and block number
~Wait event identifier and parameters
~Session identifier and session serial number
~Module and action name
~Client identifier of the session
7.Misc:-
========
Rename Tablespace:-
=================
in 10g,we can even rename a tablespace by
alter tablespace <tb_name> rename to <tb_name_new>;
This command will update the controlfile,data dictionary and datafile header,but dbf filename will be same.
**we can't rename system and sysaux tablespace.
Bigfile tablespace:-
====================
Bigfile tablespace contain only one datafile.
A bigfile tablespace with 8K blocks can contain a 32 terabyte datafile.
Bigfile tablespaces are supported only for locally managed tablespaces with automatic segment-space management.
we can take the advantage of bigfile tablespace when we are using ASM or other logical volume with RAID.
without ASM or RAID ,it gives poor response.
syntax:-
CREATE BIGFILE TABLESPACE bigtbs
Flushing Buffer Cache:-
======================
This option is same as flushing the shared pool,but only available with 10g.
but i don't know, whats the use of this command in prod database......
anyway we can check and try it on test server for tuning n testing some query etc....
SQL> alter system flush buffer_cache;
System altered.
++++++++++++++++++
8.Oracle Internal
++++++++++++++++++
Here is some stuff that is not related with 10g but have some intresting things.
a)undocumented parameter "_log_blocks_during_backup"
++++++++++++++++++++++++
as we know that oracle has generate more redo logs during hotbackup mode because
oracle has to maintain the a complete copy of block into redolog due to split block.
we can also change this behaviour by setting this parameter to False.
If Oracle block size equals the operating system block size.thus reducing the amount of redo generated
during a hot backup.
WITHOUT ORACLE SUPPORT DON'T SET IT ON PROD DATABASE.THIS DOCUMENT IS JUST FOR INFORMATIONAL PURPOSE.
b)some X$ views (X$messages)
++++++++++++++++
if you are intresting in oracle internal architecture then x$ view is right place for getting some intresting things.
X$messages :-it show all the actions that a background process do.
select * from x$messages;
like:-
lock memory at startup MMAN
Memory Management MMAN
Handle sga_target resize MMAN
Reset advisory pool when advisory turned ON MMAN
Complete deferred initialization of components MMAN
lock memory timeout action MMAN
tune undo retention MMNL
MMNL Periodic MQL Selector MMNL
ASH Sampler (KEWA) MMNL
MMON SWRF Raw Metrics Capture MMNL
reload failed KSPD callbacks MMON
SGA memory tuning MMON
background recovery area alert action MMON
Flashback Marker MMON
tablespace alert monitor MMON
Open/close flashback thread RVWR
RVWR IO's RVWR
kfcl instance recovery SMON
c)Internal Structure of Controlfile
++++++++++++++++++++++++++++++++++++
The contents of the current controlfile can be dumped in text form.
Dump Level Dump Contains
1 only the file header
2 just the file header, the database info record, and checkpoint progress records
3 all record types, but just the earliest and latest records for circular reuse record types
4 as above, but includes the 4 most recent records for circular reuse record types
5+ as above, but the number of circular reuse records included doubles with each level
the session must be connected AS SYSDBA
alter session set events 'immediate trace name controlf level 5';
This dump show lots of intresting information.
it also show rman recordes if we used this controlfile in rman backup.
Thanks
Kuljeet Pal Singh

You can find each doc in html and pdf format on the Documentation Library<br>
You can too download all the documentation in html format to have all on your own computer here (445.8MB)<br>
<br>
Nicolas.

ENTERPRIZE BACKUP UTILITY

제품 : ORACLE SERVER
작성날짜 : 1996-11-29
1. The Problem
과거 메인 프레임 환경에서 사용하던 고객들이 저 비용, C/S환경으로
Migration시에는 주로 Open system과 Oracle RDBMS를 채택하고 있다.
이런 관계로 해당 제품 시장은 고 성장을 구가하고 있기도 하다.
이러한 고 성장을 가능케 하는 요소는 물론 H/W,S/W에서의 혁신적인
진보이나, 메인 프레임급에 걸 맞는 대용량 DB를 관리하고 Backup하는
데 필수적인 System management tool은 과거와 크게 달라진 바가 없다.
tar, cpio, dd같은 UNIX backup tool들은 실제 backup media의 관리
측면에서 별 기여 를 하지 못하고 있다. 대용량 DB를 위한 Backup script는
source만 해도 수백line에 달하며 test와 troubleshoot에서도 많은 문제점을
갖고 있다. 뿐만 아니라 대용량 Database(이하 VLDB)의 Restore는
Backup보다도 훨씬 더 복잡한 문제를 갖고 있다.
최근의 Backup file이 어느 곳에 저장 되었는지를 알기 위해 Backup
tape을 분류하고, damaged file들을 restore 해야 하는 등의 일련의 작업이
필요하다.
2. The Solution
최근에 몇몇 media management vendor들은 media management기능,
scheduling기능, 강력한 security기능, UNIX system에서 제공하는 backup
tool이상의 신뢰성을 갖는 강력한backup product를 공급하기 시작했다.
이러한 product들은 system level에서의 관리를 용이하게 해주는 장점은
있으나 이미 위에서 지적된 VLDB의 backup시 제기되는 문제점들을
완전히 해결해 주지는 못한다.
Oracle7 Enterprise Backup Utility(이하 EBU)는 이런 문제점을 해결하는
solution이다. EBU는 backup/restore시 media management product와 강력한
인터페이스를 제공하며 다른 어느것과 비교 할 수 없는 강점을 갖고
있다.
3. Introducing Oracle7 Enterprise Backup Utility
EBU는 open system상에서 메인 프레임급 성능을 제공하여 한 기업
전반에 걸쳐 전략적으로 중요한 역할을 감당하게 된다. 이 utility는 DB의
신속한backup과 restore를 위해disk와 backup될 media device에서H/W
parallelism을 이용한다.open system의 full capacity를 이용하기 위해
device가 add될 때 performance가 증가된다.parallel H/W, backup
configuration check ,error detection and cleaning ,restore시의
database의block verification과 같은 특징들이EBU가 high reliability를 갖게
하는 특징들이다.
Oracle7 데이타베이스는 data files, control files, redo log files로
구성되는데 EBU는data file, control file을 backup받고 archived redo log
file을 받는다. (release2.0.8) Media failure의 경우 DB를 full restore/
partial restore가 가능하며 data file도 선택적으로 최근의 last backup까지,
어느 일정 시점 까지 만의 선택이 가능하다. 또한 recovery도 일정 시점으로
완전recovery가 가능하다.
4. Architecture
EBU는 크게 두 부분으로 구성되는데 backup하려 하는 DB에 관한 모든
current정보와history를 관리하는 catalog부분, 그리고 실행 파일 부분으로
구성된다. 실행 파일들과 catalog는 반드시 같은 host내에 존재할 필요는
없다. 실행 파일들은 다음으로 구성된다.
*obackup : 모든 다른 프로세스들을 monitor하며 backup하려하는 DB,
catalog와의 communication을 담당한다.또한 Instance Manager를
running시킨다.
*brio : obackup, brdk, brtp사이 조정 역할을 수행한다.parallel I/O
stream당 하나의 brio process가 발생한다.
*brdk : Disk file의 read/write를 조절한다. File당 하나의 brdk를 발생시키
므로 만일 여러 개의 file들을 하나의 single data stream으로 결합시
키는 경우 하나의 I/O stream내에 여러 개의 brdk process를
create한다.
*brtp : Tape file들의 read/write를 조절한다. I/O stream당 하나의 brtp
create.
*brd : Instance Manager로써 backup catalog, obackup을 monitor하는
daemon process이다. backup을 위한 cleanup과 비정상 종료된 작업을
복구 한다.
Backup동안 database file들은 disk process인 brdk에 의해 읽혀져 backup
buffer area로 넘겨지고 그 후 third vendor의 media management s/w를
경유하여 backup device에 brtp process에 의해 write된다. Restore시는
반대의 과정이 진행된다. 위의backup buffer는 hard disk와 tape device간에
발생하는 I/O상의 speed mismatch를 조절하는 역할을 한다.
5. EBU의 장점(Benefits)
Third vendor의 media management product와 함께 사용되는 EBU는
기존의 UNIX 에서 제공하는 backup tool보다 다음과 같은 강력한 장점을
지닌다.
(1) 강력한 Reliability.
*. Consistent backup procedures
기존의 hot backup script의 경우 만일 datafile이 추가될 경우 script에
새로 지정해 주어야 하며 VLDB의 경우 script만 해도 수백line에 달하여
관리상 번거로운 게 사실 이였다. 그러나 EBU의 경우는 어느 datafile이
어느directory에 위치하는지를 작업자가 알 필요가 없고 script는 짧고
단순하여 누구든 쉽게 알아볼 수 있다.
또한 DB 구성이 자동으로 확인되며 backup media를 자동으로 인식 및
관리한다.
예).full online backup script .partial online backup script
backup online database backup online
db_name = "PRODB" db_name = "PRODB"
oracle_sid = "PROD" oracle_sid = "PROD"
tablespace = "SALES"
.full restore script
restore database
db_name = "PRODB"
oracle_sid = "PROD"
이와 같이 간단한 script에 의해 DBA는 VLDB를 쉽게 backup과 restore를
할 수 있으며 작업에 필요한 세부정보는 backup catalog내에 있게 된다.
*. End-to-End checksum
Backup시 EBU는 각 backup data의 byte를 계산하고, restore시도 계산하여
정상 수행 여부를 판단 시 checksum 값을 상호 체크 한다.
*. Instance Manager
Instance Manager는 backup/restore시에 진행 상황을 monitor하고 작업
중에 에러가 발생시 복구 및 각종resource를 release시키는 기능을 담당하게
한다.
(2) High Performance
다음과 같은 EBU의 특징과 고속media device의 지원 아래 VLDB의
backup을 적은시간 내에 완전하게 수행 할 수 있게 되었다.
*. Parallel Hardware Capability
Backup/restore시 multiple device를 사용하여 동시에 여러 tablespace에
대한 작업을 수행 할 수 있다. VLDB와 같이 다수의 tablespace, datafile이
여러 disk에 분산되어 있는 경우 이와 같이 물리적으로 다수의 device를
parallel하게 사용함으로서 performance를 극대화 시킬 수 있다.
Backup시 동시 사용되는 device의 수와 performance는 정비례하게 나타난다.
*. Multiplexing
EBU는 backup device가 최고의 속도로 backup을 수행 할 수 있게 script에
지정 할 수가 있다.이것은 backup media access속도보다 disk access
속도가 훨씬 작은 경우에 여러 disk에 분산된 datafile들을 한device에
multiplexing되게 지정함으로 가능하다.
*. Null Block Compression
EBU는 backup시 null data block을 skip시키고 restore시 재구성함으로써
공간 을 절약하며 performance를 증가시킨다.
*. Buffered I/O
EBU는 disk I/O와 device I/O사이의 access speed의 mismatch를 줄이기
위하여 모든 I/O stream을 bufferring한다. 양쪽의 I/O는 shared memory
buffer를 거치게 함으로써 backup/restore수행 중 항시 일정 속도를 유지
하게 한다. shared memory는 user가 parameter로 구성할 수 있으며 기본
적으로는 parallel data stream의 개수와 buffer size에 dependent하다.
(3) Availability
한 기업에서 전략적으로 중요한 DB들은 대부분 24시간*7일 full로
가동되며, 사용 중에 backup을 수행할 수 밖에 없다. Offline full backup은
당연히 지원되며, EBU는 DB를 online상태로 full backup이 가능하며,
또한partial backup도 가능하다. 기존의 online backup이 backup으로 인해
performance를 저하시키는 단점이 있었으나 EBU는DB 운영에 최소의
영향만을 미친다.
Recovery시에도 full로 restore 시킬 수 있으며 나머지는 사용 중인
상태에서 필요 부분만 partial restore가 가능하다. 일단 EBU가 data를
restore시킨 후에는 기존의 Oracle7의 표준 recovery process가 적용되어
진다.
(4) Usability
*. Auto-configuration
Online backup을 수행 시 EBU는 current DB configuration과 backup catalog
내의 가장 최근의 configuration정보를 비교하여 backup catalog정보가 더
오래 전의 것이면 EBU는 DB의 backup직전으로 update시킨다.
Auto-configuration은 default이며 명시적으로 지정하여 disable시킬 수 있다.
Offline backup시는 backup script내에 backup command기술 전에 register
라는 명령어를 기술 해야만 configuration정보를 update시킬 수 있다.
*. Light-Out backups
Third party의 media management s/w를 이용하여 EBU를 operator의 개입 없
이 자동으로 수행이 가능하다. UNIX의 cron에서도 자동으로 수행되게 할 수
있다.
*. Raw device support
EBU는 raw device로 잡힌 DB도 operator의 특별한 조치 없이 일반 file
system의 backup과 똑같이 수행할 수 있게 한다.
*. Aggregated restore
기업의 mission-critical system에서의 backup 전략들은 흔히 partial
backup에 의존하게 된다. 이와 같은 환경에서는 backup data내의 모든file에
대한 current version을 검색하는 일이 중요한데 EBU는 이것을 자동으로
수행한다. partial backup data는 restore시 media failure이전에 취해진
가장 최근의 full backup data와 aggregated 되어져 이용된다.
*. Point-in-Time restore
EBU는 backup catalog내에 backup하려하는 DB에 대한 모든 configuration
history를 갖고 있어서, 만일 하나의 tablespace가 drop된 후 다시 필요하게
되면 비록 그 후 일정 시간이 경과되고 많은 변경이 일어났더라도 drop직전으로
일부분만 restore하여 사용이 가능하게 할 수 있다. 이 같은 tablespace는
다른 machine에 restore 될 수도 있어 현재의 DB작동에 아무 영향을 미치지
않고 수행할 수가 있다.
*. Backup catalog
EBU에 의해 제공되는 backup catalog는 모든 backup대상 DB의 configuration
과 history의 저장소로써 제공된다. backup catalog에 저장된 정보는 backup된
file, tablespace 그리고 multiplexing정보, 마지막backup이나 restore의
시간기록,backup type(full or subset),backup들이 저장 되어 있는 file set
등을 포함하고 있다. 하나의 backup catalog는 기업 내 모든 분산된 dB들을 관리
할 수 있다.
*. Dry Runs
VLDB를 backup시 겪는 문제 중 하나는 과연 script가 정상적으로 수행이 완료
되는지를 검증하는 것이다. 특별한 방법이 없는 한 긴 시간 동안 수행시켜 끝난
후 확인 할 수 밖에 없는데 EBU는 I/O없이 간단히 test로 수행을 시킬 수가
있다. 이로 인해 신뢰성 있는 backup전략을 DBA가 수립 가능하게 한다.
*. Enterprise-wide backup
이것은 backup이 단순히 single database에 국한되지 않고 한 기업 전체에
걸쳐서 global하게 수행 가능함을 말한다. 예로 전국적으로 다수의 site에
database가 구축 되어진 상황에서 각database들이 two phase commit,
snapshot 같은 분산처리 작업을 통해 다른 database들을 synchronous하게
또는 asynchronous하게 update할 경우 기업 전체를 하나의 logical
database로 보고 이런 logical database를 중앙에서 EBU를 통해 backup시킬
수가 있다.EBU는 중앙의 catalog내에 모든database들에 대한 backup정보를
간직하고 있다.
이와 같은 중앙의 한 지점을 통하여 기업 전체 모든 database들에 대한
backup수행 기능은 EBU의 가장 큰 장점 중 하나이며 이런 경우 N/W상에 대량의
data가 전송되어 network의 bandwidth가 backup의 중요한 요소로 부각된다.
6. Flexibility
*. EBU API
EBU는 앞에서도 소개되었듯이 단독으로 사용되는 것이 아니고 third-part
에서 제공하는 media management product와 같이 사용된다. 이때 두 product
사이의 interface는 backup/restore Application Programming Interface
(API Glue)에 의해서 이루어 진다. 이것은 third part에 의해 제공되며
EBU install시 installer에 의해 자동적으로 access된다.
*. Media management products
Epoch*s EpochBackup, IBM Adstar*s Distributed Storage Manager,
Legato Systems*NetWorker, HP*s Omniback*, SprectraLogic*s
Alexandria,StorageTek*s REEL, etc.
*. Media device
4mm and 8mm DATS,3480s,3490s,WORM,Writable Optical Devices and
automated systems such as stackers and silos.
7. Pricing
EBU는 무상으로 공급되며 사용을 위해서는 third vendor의 media
management product를 구입하여 설치하여야 한다.

Sure, would you clarify which DB, which OS and which product?
Concept in general is quite simple:
- stop BOE (SIA on XI3, All services, finishing with CMS on XIr2, ideally putting a sleep between all servers shutdown and CMS shutdown). NET STOP on windows.
- Backup the CMS DB (imp/exp on Oracle, mysqldump for MySQL)
- Backup the FileStore (use robocopy in a batch for delta backup)
- Restart BOE
The "catches" are around Oracle doing export in US7ASCII by default under Unix, which is a destructive conversion from UTF8 (your CMS DB should be under this format as per supported platforms), so you need to make sure to set the NLS_LANG to UTF8 on Unix user doing the backup.
Other than that, batch as shell can do all of that.
Regarding the "general" best practices, I recommend the following doc:
http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/c0020482-ca8d-2c10-9bad-d1bd332bbb28
Note on integrated BO tools: Import Wizard as biarengine are good tools for promoting a set of data between wto BOE environment or if you need to backup a specific set, but they are definitly not recommended as backup solution. I would refrain from this solution IF the point of the backup is to be able to recover the system when it crashes.
Does that answer the question?

Multiple Bolcksize (Tablespace & Buffer)

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