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Oracle: eval function

admin — Thu, 11 Feb 2010 13:40:55 +0000

The function takes some expression as the argument and executes it, returning output in the varchar string

CREATE OR REPLACE FUNCTION eval (expr VARCHAR2) RETURN VARCHAR2
AS
ret VARCHAR2(4000);
BEGIN
EXECUTE IMMEDIATE 'begin :result := ' || expr || '; end;' USING OUT ret;
RETURN ret;
END;
/

The discussion and examples could be found there

Oracle: list of the system events

admin — Wed, 10 Feb 2010 16:17:13 +0000

This piece of code show the list of events, set in the Oracle database

SET serveroutput ON
DECLARE
event_level NUMBER;
BEGIN
dbms_output.enable(20000) ;
FOR i IN 10000..33999 LOOP
sys.dbms_system.read_ev(i,event_level);
IF (event_level > 0) THEN
dbms_output.put_line('Event '||to_char(i)||' set at level '||
TO_CHAR(event_level));
END IF;
END LOOP;
END;

Oracle: list of the running transactions

admin — Tue, 09 Feb 2010 12:58:22 +0000

This query shows SID, username and start time of the running transaction.
In addition, number of the used blocks is shown.

SELECT a.sid, a.status, a.username, b.xidusn, b.used_urec, b.used_ublk, b.START_TIME
FROM v$session a, v$transaction b
WHERE a.saddr = b.ses_addr
ORDER BY START_TIME DESC;

Oracle: internal sql types

admin — Tue, 09 Feb 2010 12:51:17 +0000

Here is the list of the Oracle SQL types and their internal codes:

SELECT t.typecode,o.name
FROM sys.TYPE$ t, sys.obj$ o
WHERE
BITAND (t.properties, 16) = 16
AND t.toid = o.oid$
ORDER BY t.typecode

‘

Oracle: wait statisics by block class

admin — Tue, 09 Feb 2010 12:44:24 +0000

This query helps to get information about the wait statistics (in fact, this query is contained in GV_$WAITSTAT)

SELECT
inst_id,
DECODE (indx,
1,'data block',
2,'sort block',
3,'save undo block',
4,'segment header',
5,'save undo header',
6,'free list',
7,'extent map',
8,'1st level bmb',
9,'2nd level bmb',
10,'3rd level bmb',
11,'bitmap block',
12,'bitmap index block',
13,'file header block',
14,'unused',
15,'system undo header',
16,'system undo block',
17,'undo header',
18,'undo block'
), COUNT, TIME
FROM x$kcbwait
WHERE indx != 0;

Oracle: check the existence of logon/logoff triggers

admin — Tue, 19 Jan 2010 14:10:44 +0000

SELECT
DECODE((COUNT(trigger_name)),0,'LOGON trigger missing',
'Number of logon triggers: ' || COUNT(trigger_name) ) "INFO"
FROM sys.dba_triggers
WHERE
TRIGGERING_EVENT LIKE 'LOGON%'
AND status='ENABLED'
AND owner='SYS'
UNION
SELECT
DECODE((COUNT(trigger_name)),0,'LOGOFF trigger missing','',
'Number of logoff triggers:' || COUNT(trigger_name)) "INFO"
FROM sys.dba_triggers
WHERE
TRIGGERING_EVENT LIKE 'LOGOFF%'
AND status='ENABLED'
AND owner='SYS'

The field TRIGGERING_EVENT could have the spaces at the end! Very clever…

Oracle: redo log switches by date

admin — Fri, 08 Jan 2010 10:13:19 +0000

The following script help to find, how often the redo logs were switched.
It calculates the number by date and by hour.

SET LINESIZE 150
COLUMN DAY FORMAT A3
COLUMN Total FORMAT 99G990
COLUMN h00 FORMAT 999
COLUMN h01 FORMAT 999
COLUMN h02 FORMAT 999
COLUMN h03 FORMAT 999
COLUMN h04 FORMAT 999
COLUMN h05 FORMAT 999
COLUMN h06 FORMAT 999
COLUMN h07 FORMAT 999
COLUMN h08 FORMAT 999
COLUMN h09 FORMAT 999
COLUMN h10 FORMAT 999
COLUMN h11 FORMAT 999
COLUMN h12 FORMAT 999
COLUMN h13 FORMAT 999
COLUMN h14 FORMAT 999
COLUMN h15 FORMAT 999
COLUMN h16 FORMAT 999
COLUMN h17 FORMAT 999
COLUMN h18 FORMAT 999
COLUMN h19 FORMAT 999
COLUMN h20 FORMAT 999
COLUMN h21 FORMAT 999
COLUMN h22 FORMAT 999
COLUMN h23 FORMAT 999
COLUMN h24 FORMAT 999
BREAK ON REPORT
COMPUTE MAX OF "Total" ON REPORT
COMPUTE MAX OF "h00" ON REPORT
COMPUTE MAX OF "h01" ON REPORT
COMPUTE MAX OF "h02" ON REPORT
COMPUTE MAX OF "h03" ON REPORT
COMPUTE MAX OF "h04" ON REPORT
COMPUTE MAX OF "h05" ON REPORT
COMPUTE MAX OF "h06" ON REPORT
COMPUTE MAX OF "h07" ON REPORT
COMPUTE MAX OF "h08" ON REPORT
COMPUTE MAX OF "h09" ON REPORT
COMPUTE MAX OF "h10" ON REPORT
COMPUTE MAX OF "h11" ON REPORT
COMPUTE MAX OF "h12" ON REPORT
COMPUTE MAX OF "h13" ON REPORT
COMPUTE MAX OF "h14" ON REPORT
COMPUTE MAX OF "h15" ON REPORT
COMPUTE MAX OF "h16" ON REPORT
COMPUTE MAX OF "h17" ON REPORT
COMPUTE MAX OF "h18" ON REPORT
COMPUTE MAX OF "h19" ON REPORT
COMPUTE MAX OF "h20" ON REPORT
COMPUTE MAX OF "h21" ON REPORT
COMPUTE MAX OF "h22" ON REPORT
COMPUTE MAX OF "h23" ON REPORT

SELECT TRUNC(first_time) AS "Date",
TO_CHAR(first_time, 'Dy') AS "Day",
COUNT(1) AS "Total",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'00',1,0)) AS "h00",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'01',1,0)) AS "h01",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'02',1,0)) AS "h02",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'03',1,0)) AS "h03",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'04',1,0)) AS "h04",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'05',1,0)) AS "h05",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'06',1,0)) AS "h06",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'07',1,0)) AS "h07",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'08',1,0)) AS "h08",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'09',1,0)) AS "h09",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'10',1,0)) AS "h10",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'11',1,0)) AS "h11",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'12',1,0)) AS "h12",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'13',1,0)) AS "h13",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'14',1,0)) AS "h14",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'15',1,0)) AS "h15",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'16',1,0)) AS "h16",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'17',1,0)) AS "h17",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'18',1,0)) AS "h18",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'19',1,0)) AS "h19",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'20',1,0)) AS "h20",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'21',1,0)) AS "h21",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'22',1,0)) AS "h22",
SUM(DECODE(TO_CHAR(first_time, 'HH24'),'23',1,0)) AS "h23"
FROM V$log_history
GROUP BY TRUNC(first_time), TO_CHAR(first_time, 'Dy')
ORDER BY 1;
CLEAR BREAKS

Oracle: usage of the tablespaces

admin — Sun, 03 Jan 2010 00:16:07 +0000

SET pagesize 10000

SET COLSEP '|'
SET VERIFY off
SET serveroutput ON SIZE 1000000
BREAK ON report

COLUMN tablespace_name format a30 heading 'TABLESPACE'
COLUMN sizegb format 9999999999D9 heading 'SIZE-Gb'
COLUMN usedproc format 999D99 heading 'USED-%'
COLUMN status format a10 heading 'STATUS'
COMPUTE SUM LABEL 'Total size:' OF sizegb ON report

SELECT b.tablespace_name ,
b.bytes/1024/1024/1024 AS sizegb ,
NVL(100-((a.bytes/b.bytes)*100), 100) usedproc,
REPLACE(c.status,' ','_') status
FROM
( SELECT tablespace_name,
SUM(bytes) bytes
FROM dba_free_space
GROUP BY tablespace_name
) a ,
( SELECT tablespace_name,
SUM(bytes) bytes
FROM dba_data_files
GROUP BY tablespace_name
) b ,
dba_tablespaces c
WHERE b.tablespace_name = a.tablespace_name (+)
AND b.tablespace_name = c.tablespace_name
UNION
SELECT f.TABLESPACE_NAME,
f.TOTAL_MB/1024 sizegb,
NVL( (u.USED_MB/f.TOTAL_MB)*100, 0 ) usedproc,
'TEMPORARY' status
FROM
(
SELECT f1.TABLESPACE_NAME,SUM( f1.BYTES/1024/1024 ) TOTAL_MB
FROM (
SELECT TABLESPACE_NAME,BYTES
FROM dba_temp_files
UNION ALL
SELECT TABLESPACE_NAME,BYTES
FROM dba_data_files
WHERE TABLESPACE_NAME IN (
SELECT TABLESPACE_NAME
FROM dba_tablespaces
WHERE CONTENTS='TEMPORARY'
)
) f1
GROUP BY f1.TABLESPACE_NAME
) f,
(
SELECT u1.TABLESPACE,
SUM(u1.blocks) * MAX((SELECT VALUE FROM v$parameter WHERE name='db_block_size')/1024/1024) USED_MB
FROM v$sort_usage u1
GROUP BY u1.TABLESPACE
) u
WHERE f.TABLESPACE_NAME = u.TABLESPACE (+)
ORDER BY 1;

Oracle: plan of the running query

admin — Tue, 29 Dec 2009 11:28:04 +0000

col object_name FOR a40

SELECT operation,
options,
object_name,
partition_id
FROM v$sql_plan
WHERE address IN
( SELECT sql_address FROM v$session WHERE sid = &sid.)
ORDER BY id;

Oracle: using DBMS_METADATA for getting table structure

admin — Tue, 29 Dec 2009 10:16:10 +0000

SET LONG 5000

SELECT dbms_metadata.get_ddl('TABLE','EMP','SCOTT')
FROM dual;

Some other values of the type field for dbms_metadata.get_ddl function:

INDEX

DB_LINK

PACKAGE