How To Check Which Oracle Features are Enabled ?

There is a very good view DBA_FEATURE_USAGE_STATISTICS . Its function is to display information about database feature usage statistics. Oracle 10g will keep track of any of its features that are being used.   As an example, if we SELECT from any of the Oracle Diagnostic Pack and Tuning Pack views like V$ACTIVE_SESSION_HISTORY, the database will record our usage of it in this DBA view.  

Some of the information tracked are :

•  Name of the feature
•  Number of times the system has detected usage for the feature
•  First sample time the system detected usage of the feature
•  Last sample time the system detected usage of the feat

The below sql will give the detail of the oracle services which are being used.

SQL> select NAME, VERSION, DETECTED_USAGES, CURRENTLY_USED, FIRST_USAGE_DATE, LAST_USAGE_DATE from DBA_FEATURE_USAGE_STATISTICS where CURRENTLY_USED  = 'TRUE' order by 1,2;

Output : 

How to  check the Oracle Edition  : 
We can the check the oracle edition i.e; whether it is enterprise edition or standard edition by using the below command :

SQL>select * from product_component_version;

PRODUCT                                                     VERSION                 STATUS

----------------------------------                        -------------               ------------
NLSRTL                                                         11.2.0.1.0             Production
Oracle Database 11g Enterprise Edition      11.2.0.1.0             Production
PL/SQL                                                         11.2.0.1.0             Production
TNS for 32-bit Windows:                              11.2.0.1.0             Production


Enjoy    :-)

IMP-00010 not a valid export file header failed verification , IMP-00000:

While performing an exp/imp operation , i got IMP-00010 while importing the dumps .On googling i found that this error occur generally due to two reasons .

1.) File Corrupted During Transfer.
Note : FTP should be done in BINARY MODE

2.) When export dump file is higher version and import in lower version.
e.g; exp dump file is Oracle 10g and import in Oracle 9i

Export From            <---->   Import to   <----> Use Import/Export Utility
Version : 10.2.0.1.0 <----->   10.1.0.2.0   <----->   10.1.0.2.0
Version : 10.2.0.1.0 <----->   9.2              <----->   9.2
Version : 10.2.0.1.0 <----->   9.0.1           <----->   9.0.1

Note : Suppose we want to import 10.2.0.1.0 export dump file in 9.2.0 then we must use 9.2.0 export tools for export data from 10.2.0.1.0. and run CATEXP.SQL script which is located in Located : $ORACLE_HOME/rdbms/admin

Consider an example : Dumpfile exported in Oracle 11gr1  and has to be Imported  in 10gr1, 9i. Then use Oracle 11gr1 client (IMPORT) binary to export 11g dumpfile. Install oracle 11g client and connect to 10g,9i,8i server and import .

Enjoy     :-) 

Block Developers Tools on Production Database

I have come across a very good post on how to prevent users from using additional tools to connect to production database. This can also allow us to connect for specific users only. This can be done by creating the a AFTER LOGON trigger create ON DATABASE .Below is the script 

c:\> sqlplus / as sysdba

SQL> CREATE OR REPLACE TRIGGER block_tools_from_prod
          AFTER LOGON ON DATABASE
DECLARE
           v_prog sys.v_$session.program%TYPE;
BEGIN
         SELECT   program    INTO   v_prog
         FROM     sys.v_$session
         WHERE    audsid = USERENV('SESSIONID')
         AND   audsid != 0          ---- Don't Check SYS Connections
        AND  ROWNUM = 1;    ---- Parallel processes will have the same AUDSID's
      IF UPPER(v_prog) LIKE '%TOAD%' OR UPPER(v_prog) LIKE '%T.O.A.D%' OR   -- Toad
      UPPER(v_prog) LIKE '%SQLNAV%' OR     -- SQL Navigator
      UPPER(v_prog) LIKE '%PLSQLDEV%' OR -- PLSQL Developer
      UPPER(v_prog) LIKE '%BUSOBJ%' OR   -- Business Objects
      UPPER(v_prog) LIKE '%EXCEL%'       -- MS-Excel plug-in
  THEN
     RAISE_APPLICATION_ERROR(-20000, 'Development tools are not allowed here.');
  END IF;
END;
/

Reference : http://psoug.org/snippet.htm/Block_TOAD_and_other_tools_516.htm


Enjoy    :-)

Determine OS block size for Linux and Windows

A block is a uniformly sized unit of data storage for a filesystem. Block size can be an important consideration when setting up a system that is designed for maximum performance. 

Block size in Linux :  If we want to confirm the block size of any filesystem of Ubuntu or any other Linux OS, tune2fs command is here to help:

ubuntu# tune2fs -l /dev/sda1 | grep Block
Block count:              4980736
Block size:                 4096
Blocks per group:       32768

From this example, we can see that the default block size for the filesystem on  /dev/sda1 partition is 4096 bytes, or 4k. That's the default block size for ext3 filesystem.

OS block size in Solaris : 

$perl -e '$a=(stat ".")[11]; print $a'
8192

or 
$df -g | grep 'block size' 

Block size in Window Machine  : If  OS  is using ntfs system use the below command  :

C:\>fsutil fsinfo ntfsinfo D:
NTFS Volume Serial Number :        0x7a141d52141d12ad
Version :                                          3.1
Number Sectors :                            0x00000000036b17d0
Total Clusters :                                0x00000000006d62fa
Free Clusters  :                               0x00000000001ed190
Total Reserved :                             0x0000000000000170
Bytes Per Sector  :                         512
Bytes Per Cluster :                     4096   <<===   (block size)
Bytes Per FileRecord Segment       : 1024
Clusters Per FileRecord Segment   : 0
Mft Valid Data Length :                    0x0000000005b64000
Mft Start Lcn  :                                 0x00000000000c0000
Mft2 Start Lcn :                                0x000000000036b17d
Mft Zone Start :                                0x000000000043c9c0
Mft Zone End   :                               0x000000000044b460

or we can also find the block size as : 

--> Go to "My Computer"   --> manage --> Disk Defragmenter --> select any disk -->  click on "analyze" button , then it will present us a report and in that report "Cluster Size" represents the  OS "Block Size".

Enjoy   :-)

When To Use Database Resident Connection Pooling

Database resident connection pooling is useful when multiple clients access the database and when any of the following apply  :

• A large number of client connections need to be supported with minimum memory usage.
• The client applications are similar and can share or reuse sessions.
• Applications are similar if they connect with the same database credentials and use the same schema.
• The client applications acquire a database connection, work on it for a relatively short duration, and then release it.
• Session affinity is not required across client requests.
• There are multiple processes and multiple hosts on the client side.

Advantages of Database Resident Connection Pooling : Using database resident connection pooling provides the following advantages :

• Enables resource sharing among multiple middle-tier client applications.
• Improves scalability of databases and applications by reducing resource usage.
• Provides pooling for architectures with multi-process, single-threaded application servers.

Enjoy   :-)