Oracle DBA – Tips and Techniques

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Archive for the ‘Monitoring’ Category

Script – Monitor Flashback Logs

Posted by Gavin Soorma on July 9, 2009

PROMPT How Far Back Can We Flashback To (Time)?
PROMPT
select to_char(oldest_flashback_time,'dd-mon-yyyy hh24:mi:ss') "Oldest Flashback Time"
 from v$flashback_database_log;

PROMPT
PROMPT How Far Back Can We Flashback To (SCN)?
PROMPT
col oldest_flashback_scn format 99999999999999999999999999
select oldest_flashback_scn from v$flashback_database_log;

PROMPT
PROMPT Flashback Area Usage
SELECT * FROM   V$FLASH_RECOVERY_AREA_USAGE;

PROMPT
col ROUND(SPACE_LIMIT/1048576) heading "Space Allocated (MB)" format 999999
col round(space_used/1048576) heading "Space Used (MB)" format 99999
col name Heading "Flashback Location" format a40

select name, round(space_limit/1048576),round(space_used/1048576)
 from  v$RECOVERY_FILE_DEST;

How Far Back Can We Flashback To (Time)?

Oldest Flashback Time
-----------------------------
05-jul-2009 22:53:07

How Far Back Can We Flashback To (SCN)?

       OLDEST_FLASHBACK_SCN
---------------------------
                15321928761

Flashback Area Usage

FILE_TYPE    PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES
------------ ------------------ ------------------------- ---------------
CONTROLFILE                   0                         0               0
ONLINELOG                     0                         0               0
ARCHIVELOG                16.33                     16.33              51
BACKUPPIECE               16.34                     16.34               6
IMAGECOPY                     0                         0               0
FLASHBACKLOG              45.94                     10.61             204

6 rows selected.

Flashback Location                       Space Allocated (MB) Space Used (MB)
---------------------------------------- -------------------- ---------------
/u05/oradata/flash_recovery_area                         5120            4025

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Script – Temporary tablespace usage

Posted by Arjun Raja on June 30, 2009

– Listing of temp segments.–

SELECT A.tablespace_name tablespace, D.mb_total,
SUM (A.used_blocks * D.block_size) / 1024 / 1024 mb_used,
D.mb_total – SUM (A.used_blocks * D.block_size) / 1024 / 1024 mb_free
FROM v$sort_segment A,
(
SELECT B.name, C.block_size, SUM (C.bytes) / 1024 / 1024 mb_total
FROM v$tablespace B, v$tempfile C
WHERE B.ts#= C.ts#
GROUP BY B.name, C.block_size
) D
WHERE A.tablespace_name = D.name
GROUP by A.tablespace_name, D.mb_total;

– Temp segment usage per session.–

SELECT S.sid || ‘,’ || S.serial# sid_serial, S.username, S.osuser, P.spid, S.module,
P.program, SUM (T.blocks) * TBS.block_size / 1024 / 1024 mb_used, T.tablespace,
COUNT(*) statements
FROM v$sort_usage T, v$session S, dba_tablespaces TBS, v$process P
WHERE T.session_addr = S.saddr
AND S.paddr = P.addr
AND T.tablespace = TBS.tablespace_name
GROUP BY S.sid, S.serial#, S.username, S.osuser, P.spid, S.module,
P.program, TBS.block_size, T.tablespace
ORDER BY sid_serial;

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Monitor long running operations using v$session_longops

Posted by Gavin Soorma on June 30, 2009

SELECT SID, SERIAL#, opname, SOFAR, TOTALWORK,
ROUND(SOFAR/TOTALWORK*100,2) COMPLETE
FROM   V$SESSION_LONGOPS
WHERE
TOTALWORK != 0
AND    SOFAR != TOTALWORK
order by 1;

Note: the same query can be used to monitor RMAN backup status

SELECT SID, SERIAL#, CONTEXT, SOFAR, TOTALWORK,
       ROUND(SOFAR/TOTALWORK*100,2) "%_COMPLETE"
FROM V$SESSION_LONGOPS
WHERE OPNAME LIKE 'RMAN%'
  AND OPNAME NOT LIKE '%aggregate%'
  AND TOTALWORK != 0
  AND SOFAR  != TOTALWORK
;

       SID    SERIAL# OPNAME                    SOFAR  TOTALWORK   COMPLETE
---------- ---------- -------------------- ---------- ---------- ----------
       604      13371 Table Scan                 6311      24498      25.76
       685       1586 Table Scan                 6333      24498      25.85

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Monitor Data Guard Log Shipping

Posted by Gavin Soorma on June 30, 2009

Note: This query needs to be run on the Primary database.

SET PAGESIZE 124
COL DB_NAME FORMAT A8
COL HOSTNAME FORMAT A12
COL LOG_ARCHIVED FORMAT 999999
COL LOG_APPLIED FORMAT 999999
COL LOG_GAP FORMAT 9999
COL APPLIED_TIME FORMAT A12
SELECT DB_NAME, HOSTNAME, LOG_ARCHIVED, LOG_APPLIED,APPLIED_TIME,
LOG_ARCHIVED-LOG_APPLIED LOG_GAP
FROM
(
SELECT NAME DB_NAME
FROM V$DATABASE
),
(
SELECT UPPER(SUBSTR(HOST_NAME,1,(DECODE(INSTR(HOST_NAME,'.'),0,LENGTH(HOST_NAME),
(INSTR(HOST_NAME,'.')-1))))) HOSTNAME
FROM V$INSTANCE
),
(
SELECT MAX(SEQUENCE#) LOG_ARCHIVED
FROM V$ARCHIVED_LOG WHERE DEST_ID=1 AND ARCHIVED='YES'
),
(
SELECT MAX(SEQUENCE#) LOG_APPLIED
FROM V$ARCHIVED_LOG WHERE DEST_ID=2 AND APPLIED='YES'
),
(
SELECT TO_CHAR(MAX(COMPLETION_TIME),'DD-MON/HH24:MI') APPLIED_TIME
FROM V$ARCHIVED_LOG WHERE DEST_ID=2 AND APPLIED='YES'
);

DB_NAME  HOSTNAME     LOG_ARCHIVED LOG_APPLIED APPLIED_TIME LOG_GAP
-------- ------------ ------------ ----------- ------------ -------
CPSPRD   PRDU009N1           11213       11213 30-JUN/08:48       0

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Identify active transactions in undo and rollback segments

Posted by Gavin Soorma on June 29, 2009

col o format a10
col u format a10
select osuser o, username u, sid,
segment_name s, substr(sa.sql_text,1,200) txt
from v$session s,
v$transaction t,
dba_rollback_segs r,
v$sqlarea sa
where s.taddr=t.addr
and t.xidusn=r.segment_id(+)
and s.sql_address=sa.address(+)
And substr(sa.sql_text,1,200) is not null
order by 3;

col name format a8
col username format a8
col osuser format a8
col start_time format a17
col status format a12
tti 'Active transactions'
select username, osuser,
t.start_time, r.name, t.used_ublk "ROLLB BLKS",
decode(t.space, 'YES', 'SPACE TX',
decode(t.recursive, 'YES', 'RECURSIVE TX',
decode(t.noundo, 'YES', 'NO UNDO TX', t.status)
)) status
from sys.v_$transaction t, sys.v_$rollname r, sys.v_$session s
where t.xidusn = r.usn
and t.ses_addr = s.saddr
/

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Locked Sessions and Locked Objects

Posted by Gavin Soorma on June 29, 2009

PROMPT Blocked and Blocker Sessions

col blocker_sid format 99999999999
col blocked_sid format 99999999999
col min_blocked format 99999999999
col request format 9999999
select /*+ ORDERED */
blocker.sid blocker_sid
, blocked.sid blocked_sid
, TRUNC(blocked.ctime/60) min_blocked
, blocked.request
from (select *
from v$lock
where block != 0
and type = 'TX') blocker
, v$lock blocked
where
blocked.type='TX'
and blocked.block = 0
and blocked.id1 = blocker.id1;

prompt blocked objects from V$LOCK and SYS.OBJ$

set lines 132
col BLOCKED_OBJ format a35 trunc
select /*+ ORDERED */
l.sid
, l.lmode
, TRUNC(l.ctime/60) min_blocked
, u.name||'.'||o.NAME blocked_obj
from (select *
from v$lock
where type='TM'
and sid in (select sid
from v$lock
where block!=0)) l
, sys.obj$ o
, sys.user$ u
where o.obj# = l.ID1
and o.OWNER# = u.user#
/

prompt blocked sessions from V$LOCK

select /*+ ORDERED */
blocker.sid blocker_sid
, blocked.sid blocked_sid
, TRUNC(blocked.ctime/60) min_blocked
, blocked.request
from (select *
from v$lock
where block != 0
and type = 'TX') blocker
, v$lock blocked
where blocked.type='TX'
and blocked.block = 0
and blocked.id1 = blocker.id1
/

prompt blokers session details from V$SESSION

set lines 132
col username format a10 trunc
col osuser format a12 trunc
col machine format a15 trunc
col process format a15 trunc
col action format a50 trunc
SELECT sid
, serial#
, username
, osuser
, machine
FROM v$session
WHERE sid IN (select sid
from v$lock
where block != 0
and type = 'TX')
/

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Script- Track redo generation by day

Posted by Gavin Soorma on June 20, 2009


select trunc(completion_time) rundate
,count(*)  logswitch
,round((sum(blocks*block_size)/1024/1024)) "REDO PER DAY (MB)"
from v$archived_log
group by trunc(completion_time)
order by 1;

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Redo Log File Switches – By hour of the day

Posted by Gavin Soorma on June 18, 2009

prompt
prompt "Morning .........."
select to_char(first_time,'DD/MON') day,
to_char(sum(decode(to_char(first_time,'HH24'),'07',1,0)),'000')"07",
to_char(sum(decode(to_char(first_time,'HH24'),'08',1,0)),'000')"08",
to_char(sum(decode(to_char(first_time,'HH24'),'09',1,0)),'000')"09",
to_char(sum(decode(to_char(first_time,'HH24'),'10',1,0)),'000')"10",
to_char(sum(decode(to_char(first_time,'HH24'),'11',1,0)),'000')"11",
to_char(sum(decode(to_char(first_time,'HH24'),'12',1,0)),'000')"12",
to_char(sum(decode(to_char(first_time,'HH24'),'13',1,0)),'000')"13",
to_char(sum(decode(to_char(first_time,'HH24'),'14',1,0)),'000')"14",
to_char(sum(decode(to_char(first_time,'HH24'),'15',1,0)),'000')"15",
to_char(sum(decode(to_char(first_time,'HH24'),'16',1,0)),'000')"16",
to_char(sum(decode(to_char(first_time,'HH24'),'17',1,0)),'000')"17",
to_char(sum(decode(to_char(first_time,'HH24'),'18',1,0)),'000')"18"
from v$log_history
WHERE TRUNC(FIRST_TIME) > TRUNC(SYSDATE) - 7
group by to_char(first_time,'DD/MON');
prompt
prompt
Prompt "Evening ........"
prompt
select to_char(first_time,'DD/MON') day,
to_char(sum(decode(to_char(first_time,'HH24'),'19',1,0)),'000')"19",
to_char(sum(decode(to_char(first_time,'HH24'),'20',1,0)),'000')"20",
to_char(sum(decode(to_char(first_time,'HH24'),'21',1,0)),'000')"21",
to_char(sum(decode(to_char(first_time,'HH24'),'22',1,0)),'000')"22",
to_char(sum(decode(to_char(first_time,'HH24'),'23',1,0)),'000')"23",
to_char(sum(decode(to_char(first_time,'HH24'),'00',1,0)),'000') "00",
to_char(sum(decode(to_char(first_time,'HH24'),'01',1,0)),'000')"01",
to_char(sum(decode(to_char(first_time,'HH24'),'02',1,0)),'000')"02",
to_char(sum(decode(to_char(first_time,'HH24'),'03',1,0)),'000')"03",
to_char(sum(decode(to_char(first_time,'HH24'),'04',1,0)),'000')"04",
to_char(sum(decode(to_char(first_time,'HH24'),'05',1,0)),'000')"05",
to_char(sum(decode(to_char(first_time,'HH24'),'06',1,0)),'000')"06"
from v$log_history
WHERE TRUNC(FIRST_TIME) > TRUNC(SYSDATE) - 7
group by to_char(first_time,'DD/MON');

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