Nov 14, 2011

Oracle WorkspaceManager ErrorC0des



 
exec dbms_wm.enableversioning('TABLEA');

ORA-20129: table 'TABLEA' does not exist
ORA-06512: at "WMSYS.LT", line 9175
ORA-06512: at line 1

This error is due to that the table does not exist in the current schema for version enabling  


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exec dbms_wm.disableversioning('TABLEA');

ORA-20132: table 'TABLEA' is not version enabled
ORA-06512: at "WMSYS.LT", line 9355
ORA-06512: at line 1

This error is due to that the table does not exist in the current schema for version disabling

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 exec dbms_wm.enableversioning('USER_RECORDSS_ON_01_SEP_2011')

ORA-20136: table names are limited to 25 characters
ORA-06512: at "WMSYS.LT", line 9175
ORA-06512: at line 1

In an Oracle Workspace Manager only 25 characters named tables are allowed to version enbale


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Nov 1, 2011

ORA-20061 ,ORA-00604 and ORA-2017



ORA-00604: error occurred at recursive SQL level 1
ORA-20061: versioned objects have to be version disabled before being dropped
ORA-06512: at "WMSYS.WM_ERROR", line 338
ORA-06512: at "WMSYS.WM_ERROR", line 346
ORA-06512: at "WMSYS.NO_VM_DROP_PROC", line 42

One scenario where  this error is , when you try to drop TESTVERSION_LT  table

If this error is occuring and not able to drop the 'TESTVERSION_LT' table and also not able to version disable the 'TESTVERSION'

FIRST take the backup of TESTVERSION table as
create table TESTVERSION_back as select * from TESTVERSION 
 and create all the indexes on that TESTVERSION_back table
.SECOND try to delete the entry of that table   from WM$VERSIONED_TABLES table and the try to drop VIEW  TESTVERSION AND TESTVERSION_LT  TABLE


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ORA-00604: error occurred at recursive SQL level 1
ORA-20171: WM error: Versioned objects cannot be altered.


alter table TESTVERSION_lt add VERSION INTEGER


FIRST take the backup of TESTVERSION table as create table TESTVERSION_back as select * from TESTVERSION and create all the indexes on that TESTVERSION_back table

SECOND try to delete the entry of that table for example from WM$VERSIONED_TABLES table and the try to drop VIEW TESTVERSION AND TESTVERSION_LT TABLE

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Compressed Tables Cannot Versiondisable


create table testversion ( pkl number primary key,s_var varchar2(10));

ALTER TABLE TESTVERSION CACHE COMPRESS  PARALLEL ( DEGREE Default INSTANCES Default );

exec dbms_wm.enableversioning('TESTVERSION');

exec dbms_wm.disableversioning('TESTVERSION');

ORA-20231: 'TESTVERSION'  failed during DisableVersioning. Error:
ORA-39726: unsupported add/drop column operation on compressed tables .


  This error occurs when we try to version disable a  compressed table ;its  because during version enabling a compressed table   four columns  VERSION, NEXTVER, DELSTATUS, LTLOCK are not created

SO THERE IS NO USE TO VERSION ENABLE A COMPRESSED TABLE BECAUSE FOLLOWING 
VERSION, NEXTVER, DELSTATUS, LTLOCK COLUMNS ARE NOT CREATED WHICH ARE THE NUCLUES OF THE VERSIONING 


WHEN A COMPRESSED TABLE IS VERSION ENABLED ONLY  A VIEW NAMED 'TESTVERSION' IS CREATED .NO TRIGGERS AND OTHER VIEWS ARE CREATED


WHEN A COMPRESSED TABLE IS TRIED TO VERSION DISABLED ITS STATE IS CHANGED TO 'DV' .EVEN THOUGHT IT THROWS ERROR

CHECK THE BELOW QUERY FOR VERSIONED STATUS OF A TABLE

SELECT DISABLING_VER,UNDO_CODE FROM WMSYS.WM$VERSIONED_TABLES WHERE OWNER='SCHEMAMERGE' AND TABLE_NAME='TESTVERSION' ;

AND IF YOU CHECK IN UNDO_CODE COLUMN OF THIS WMSYS.WM$VERSIONED_TABLES TABLE YOU CAN GET WHY VERSION DISABLE OF THE COMPRESSED TABLE DEOSNT WORK

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Oct 27, 2011

Tablespace Data mining

    Tablespace Data mining
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      Let me call some of my findings as Oracle Tablespace Data minig some I dont know really what to name this some may call it as Tablespace cracking or hacking but I dont think so ;because what i done is just some analysis with  my current Database and its . DBF and .LOG file so we can call Tablespace Data-mining .


Note : When you are experimenting try to copy .DBF and .LOG file and experiment on the copied file .Most probably you may more details other than mentioned here .
Do experiment
.This is for non-encrypted tablespace


        In Redo Tablespace it records the changes , If you open the RED.LOG file in a text editor you will get dbms_job's 'WHAT' details if a procedure or function is given if query is given we will not get the query detail .Then NLS_LANGUAGE parameter can be searched then search for MAXVALUE keyword

If you open the tablespace you created for a particular schema or Database you will able to see what all data are stored in that DB in that tablespace

Aug 17, 2011

Oracle Exdata



Exdata is a hardware machine which runs oracle database; supports OLTP, Database
Exologic is a hardware machine for application and primarily for cloud computing
Exadata X2-2 Hardware Architecture (FULL Rack)
DBA's has to think about storage server, DB server, storage connecting devices, fiber channel connectivity, Network components, OS, storage drives this all includes in Exdata

In Storage Grid of Exdata it contains 2 Xenon CPU with computing power which take care of processing inside the storages 
Flash is the key performance of Exdata machine. Its a kind of h/w in a pci slot where all your data is stored intermediately between db server and storage server. 
InfiniBand Networks (fiber channel has only 10gb/s) which is also a key performance of Exdata ;which used to transfer data between db server to storage which has high bandwidth

In Exdata is a preconfigured plug and play software .

Key Performance of Exdata
1)      Intelligent Storage Grid

2)      Hybrid Columnar Compression will compress 10 times the data

3)      Smart Flash Cache (patented product of Oracle) different from SSD; it’s a second SGA at storage level which also contains algorithm which drives the flash cache.



In Traditional San if we increase the storage it will not increase the db performance because the spindles of hardware will perform as usual to read from storage
In Exdata there storage is intelligent.  (www.tpc.org to get which is the fastest machine)
ROW level locking
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it means any moment of time any person can do DML at a moment of time so entire table is locked ,so oracle introduced rowlevel locking mechanism which makes oracle faster
Rowlevel is managed at block level ultimate storage element of ur row.
RMAN is the backup in exdata