This blog contains experience gained over the years of implementing (and de-implementing) large scale IT applications/software.

Tag: sql

Kill All Oracle Sessions For Specific User – 11gR2

Here’s a small script to display, then kill all sessions in an Oracle 11gR2 database for a specific username.

First let’s check the sessions of the specific username:

NOTE: Change “<USER NAME HERE>” in both blocks of code, for the actual username to be killed.

SQL> set serveroutput on size 10000;
SELECT sid,serial#
  FROM v$session
WHERE username = '<USER NAME HERE>';

Now run the code to kill the user sessions:

SQL> DECLARE
   dummy NUMBER;
   c     NUMBER := dbms_sql.open_cursor;
BEGIN
   FOR c1_row IN (SELECT sid,serial#
                  FROM v$session
                  WHERE username = '<USER NAME HERE>') LOOP
      DBMS_OUTPUT.PUT_LINE('Killing session: '||c1_row.sid||' serial#: '||c1_row.serial#);
      DBMS_SQL.PARSE(c,'alter system kill session '||''''||c1_row.sid||','||c1_row.serial#||'''',dbms_sql.NATIVE);
      dummy := DBMS_SQL.EXECUTE(c);
      DBMS_OUTPUT.PUT_LINE('Session: '||c1_row.sid||' serial#: '||c1_row.serial#||' killed.');
   END LOOP;

   dbms_sql.close_cursor(c);
EXCEPTION
   WHEN OTHERS THEN
      DBMS_OUTPUT.PUT_LINE(SUBSTR(SQLERRM,1,250));
END;
/

You can now run the check code again to see that all sessions for the user have been killed.

Find RMAN Backup Statistics

You can query the view V$BACKUP_SYNC_IO (for synchronous tape devices) to obtain the average MB transfer speed from RMAN to the tape device (or intermediary software if using the obk interface):

SQL> select avg(EFFECTIVE_BYTES_PER_SECOND)/1024/1024 MB_per_s
       from V$BACKUP_SYNC_IO
      where DEVICE_TYPE='SBT_TAPE';
MB_PER_S
-----------
16.1589822

Oracle 11g Methods of Performance Tuning SQL

>90% of upgrade related problems are performance issues after an upgrade.

Source: Oracle Corp

Oracle tools for helping you tune the database:

  • Statspack – FREE – (See note 394937.1)

  • AWR – Diagnostics Pack & Tuning Pack license required.
  • Real Application Testing (Features: SQL Performance Analyser & Database Replay) – Tuning Pack license required.

Since 11g, Oracle recommend, instead of: storing outlines, fixing stats, using SQL hints, using the Rule Based Optimiser (desupported); you should use the SQL Plan Management tool along with SQL Profiling.

See spm_white_paper_ow07.pdf for more information.

SQL_OPCODE values from an 11gR2 Database

If you have a need to find the actual numeric operation code for different SQL operations, then this is possible if you can access the ASH table as highlighted below.

The snapshot was taken from an 11gR2 database:

SQL> select distinct sql_opname,
                     sql_opcode
       from dba_hist_active_sess_history;

SQL_OPNAME                SQL_OPCODE
------------------------- -----------------
ALTER TABLESPACE          40
DELETE                    7
ALTER DATABASE            35
ANALYZE TABLE             62
ALTER TABLE               15
INSERT                    2
UPSERT                    189
ALTER SUMMARY             172
CREATE TABLE              1
SELECT                    3
LOCK TABLE                26
CREATE INDEX              9
PL/SQL EXECUTE            47
TRUNCATE TABLE            85
CALL METHOD               170
                          0
UPDATE                    6

I guess the newer the “feature” the higher the number, since Oracle couldn’t just go and change the number between releases.

HowTo: Query to show SAP roles and transaction codes by user

Scenario: You have been requested to provide a list of all roles currently assigned to your SAP user accounts, plus the transaction codes that are assigned to each role and user account.

HINT: To be able to do this within SAP, you can use the SAP QuickViewer (SQVI) to create a query and join the required tables. You could then generate a program and then copy it to create your own Z-report.

Using the following Oracle SQL*Plus query at the database level, will allow you to produce a report containing the USERNAME, ROLENAME, TCODE_RANGE_START and TCODE_RANGE_END.

set linesize 500 pagesize 9999 newpage none recsep none
SELECT u.uname USERNAME,
               r.agr_name ROLENAME,
               r.low TCODE_RANGE_START,
               r.high TCODE_RANGE_END
  FROM agr_1251 r,
       (select mandt,
               uname,
               agr_name
          from agr_users) u
 WHERE r.agr_name = u.agr_name
   AND r.mandt = u.mandt
   AND r.mandt = <YOUR CLIENT>
   AND r.object='S_TCODE'
ORDER BY u.uname,r.agr_name,r.low,r.high;

NOTE: You should adjust “<YOUR CLIENT>” to be the client number you wish to check.

You should note that TCODE_RANGE_START and TCODE_RANGE_END could contain wild cards as per the usual methods of providing a range of values to an authorisation object in PFCG.