The Monitoring of predefined events that generates a message or
warning when a certain threshold has been exceeded. This is done in an
effort to ensure that an issue doesn’t become a problem.
The database
monitoring is required for the following reason:
– Smooth running of production
– Keeping an eye on development
– Database performance
– In Support of an SLA (service level agreement)
Types of DB Monitoring
1. Status
2. Performance
3. Trend Analysis
Status Monitoring:
Monitor the current status of an event and reports when it exceeds a defined threshold.
Database:
– Database/Listener
– Monitor Alert. log Message on regular basis.
– Check all last night backup is successful.
– Tablespace/Datafiles full or Fragmented.
– Identify bad growth of segment.
– Identify at least 1 top resource consuming query
– Monitor Locking
– Check Maximum Extent about to be reached.
– Redo log Tracking
– UNDO and Temp Segment Free space.
– Monitor Running Job
– Tracking DB User/Session Information.
– Important Object Information
OS:
– SGA/PGA information
– CPU Usage Information
– Memory Utilization
– Disk Utilization
Performance Monitoring:
Monitor a defined set of performance statistics. This is done in an effort to maintain the best possible DB performance.
Trend Analysis Monitoring:
Collect the historical data for specified events and analyze these data
on schedule basis to reveal any potential problems. For Example watching
growth of data in a tablespace and predicting when it will fill.
Apart from the above checklist some of the other checklist a DBA are
using. It is depend on the requirement. I am mentioning here some of the
related query and scripts. It is fully related to DB Monitoring
Purpose.
Note: Keep every one informed specially your senior or Junior DBA,
System Admin, Manager and do not forget to document very important
update.
Database Information:
Track OS Reboot Time:
net statistics server
systeminfo | find “Up Time” — to find system last uptime
systeminfo | find “System Boot Time” — to find system boot time
net statistics workstation | find “Statistics” Workstation Statistics for \\A5541TAG-WKS –perticular workstation statistics
Database and Instance Last start time:
SELECT to_char(startup_time,’DD-MON-YYYY HH24:MI:SS’) “DB Startup Time”
FROM sys.v_$instance;
SELECT SYSDATE-logon_time “Days”, (SYSDATE-logon_time)*24 “Hours”
from sys.v_$session where sid=1;
Track Database Version:
SELECT * from v$version;
Track Database Name and ID information:
SELECT DBID, NAME FROM V$DATABASE;
Track Database Global Name information:
SELECT * FROM GLOBAL_NAME;
Track Database Instance name:
SELECT INSTANCE_NAME FROM V$INSTANCE;
Track Database Host Details:
SELECT UTL_INADDR.GET_HOST_ADDRESS, UTL_INADDR.GET_HOST_NAME FROM DUAL;
Track Database Present Status:
SELECT created, RESETLOGS_TIME, Log_mode FROM V$DATABASE;
DB Character Set Information:
Select * from nls_database_parameters;
Track Database default information:
Select username, profile, default_tablespace, temporary_tablespace from dba_users;
Track Total Size of Database:
select a.data_size+b.temp_size+c.redo_size “Total_Size (GB)”
from ( select sum(bytes/1024/1024/1024) data_size
from dba_data_files ) a, ( select nvl(sum(bytes/1024/1024/1024),0) temp_size
from dba_temp_files ) b, ( select sum(bytes/1024/1024/1024) redo_size
from sys.v_$log ) c;
Total Size of Database with free space:
Select round(sum(used.bytes) / 1024 / 1024/1024 ) || ‘ GB’ “Database
Size”,round(free.p / 1024 / 1024/1024) || ‘ GB’ “Free space”
from (select bytes from v$datafile
union all
select bytes from v$tempfile
union all
select bytes from v$log) used, (select sum(bytes) as p from dba_free_space) free group by free.p;
Track Database Structure:
select name from sys.v_$controlfile
/
select group#,member from sys.v_$logfile
/
Select F.file_id Id, F.file_name name, F.bytes/(1024*1024) Mbyte,
decode(F.status,’AVAILABLE’,'OK’,F.status) status, F.tablespace_name Tspace
from sys.dba_data_files F
order by tablespace_name;
Tablespace/Datafile/Temp/UNDO Information:
Track Tablespace Used/Free Space:
SELECT /* + RULE */ df.tablespace_name “Tablespace”, df.bytes / (1024 * 1024) “Size (MB)”,
SUM(fs.bytes) / (1024 * 1024) “Free (MB)”,
Nvl(Round(SUM(fs.bytes) * 100 / df.bytes),1) “% Free”, Round((df.bytes –
SUM(fs.bytes)) * 100 / df.bytes) “% Used”
FROM dba_free_space fs, (SELECT tablespace_name,SUM(bytes) bytes
FROM dba_data_files
GROUP BY tablespace_name) df
WHERE fs.tablespace_name (+) = df.tablespace_name
GROUP BY df.tablespace_name,df.bytes
UNION ALL
SELECT /* + RULE */ df.tablespace_name tspace,
fs.bytes / (1024 * 1024), SUM(df.bytes_free) / (1024 * 1024),
Nvl(Round((SUM(fs.bytes) – df.bytes_used) * 100 / fs.bytes), 1),
Round((SUM(fs.bytes) – df.bytes_free) * 100 / fs.bytes)
FROM dba_temp_files fs, (SELECT tablespace_name,bytes_free,bytes_used
FROM v$temp_space_header
GROUP BY tablespace_name,bytes_free,bytes_used) df
WHERE fs.tablespace_name (+) = df.tablespace_name
GROUP BY df.tablespace_name,fs.bytes,df.bytes_free,df.bytes_used
ORDER BY 4 DESC;
Track all Tablespaces with free space < 10%
Select a.tablespace_name,sum(a.tots/1048576) Tot_Size, sum(a.sumb/1024)
Tot_Free, sum(a.sumb)*100/sum(a.tots) Pct_Free, ceil((((sum(a.tots) *
15) – (sum(a.sumb)*100))/85 )/1048576) Min_Add
from (select tablespace_name,0 tots,sum(bytes) sumb
from dba_free_space a
group by tablespace_name
union
Select tablespace_name,sum(bytes) tots,0 from dba_data_files
group by tablespace_name) a group by a.tablespace_name
having sum(a.sumb)*100/sum(a.tots) < 10
order by pct_free;
Track Tablespace Fragmentation Details:
Select a.tablespace_name,sum(a.tots/1048576) Tot_Size,
sum(a.sumb/1048576) Tot_Free, sum(a.sumb)*100/sum(a.tots) Pct_Free,
sum(a.largest/1024) Max_Free,sum(a.chunks) Chunks_Free
from ( select tablespace_name,0 tots,sum(bytes) sumb,
max(bytes) largest,count(*) chunks
from dba_free_space a
group by tablespace_name
union
select tablespace_name,sum(bytes) tots,0,0,0 from dba_data_files
group by tablespace_name) a group by a.tablespace_name
order by pct_free;
Track Non-Sys owned tables in SYSTEM Tablespace:
SELECT owner, table_name, tablespace_name FROM dba_tables WHERE
tablespace_name = 'SYSTEM' AND owner NOT IN ('SYSTEM', 'SYS', 'OUTLN');
Track Default and Temporary Tablespace:
SELECT * FROM DATABASE_PROPERTIES where PROPERTY_NAME like '%DEFAULT%';
select username,temporary_tablespace,default_tablespace from dba_users where username='HRMS'; –for Particular User
Select default_tablespace,temporary_tablespace,username from dba_users; –for All Users
Track DB datafile used and free space:
SELECT SUBSTR (df.NAME, 1, 40) file_name,dfs.tablespace_name, df.bytes /
1024 / 1024 allocated_mb, ((df.bytes / 1024 / 1024) – NVL (SUM
(dfs.bytes) / 1024 / 1024, 0)) used_mb,
NVL (SUM (dfs.bytes) / 1024 / 1024, 0) free_space_mb
FROM v$datafile df, dba_free_space dfs
WHERE df.file# = dfs.file_id(+)
GROUP BY dfs.file_id, df.NAME, df.file#, df.bytes,dfs.tablespace_name
ORDER BY file_name;
Track Datafile with Archive Details:
SELECT NAME, a.status, DECODE (b.status, 'Active', 'Backup', 'Normal')
arc, enabled, bytes, change#, TIME ARCHIVE FROM sys.v_$datafile a,
sys.v_$backup b WHERE a.file# = b.file#;
Track Datafiles with highest I/O activity:
Select * from (select name,phyrds, phywrts,readtim,writetim
from v$filestat a, v$datafile b
where a.file#=b.file#
order by readtim desc) where rownum 0
ORDER BY elapsed_seconds;
Track Running RMAN backup status:
SELECT SID, SERIAL#, CONTEXT, SOFAR, TOTALWORK,
ROUND(SOFAR/TOTALWORK*100,2) “%_COMPLETE”
FROM V$SESSION_LONGOPS
WHERE OPNAME LIKE ‘RMAN%’ AND OPNAME NOT LIKE ‘%aggregate%’
AND TOTALWORK != 0 AND SOFAR != TOTALWORK;
Monitor Import Rate:
Oracle Import Utility usually takes hours for very large tables and we
need to track the execution of Oracle Import Process. Below option can
help you monitor the rate at which rows are being imported from a
running import job.
select substr(sql_text,instr(sql_text,’into “‘),30) table_name,
rows_processed, round((sysdate-to_date(first_load_time,’yyyy-mm-dd hh24:mi:ss’))*24*60,1) minutes,
trunc(rows_processed/((sysdate-to_date(first_load_time,’yyyy-mm-dd hh24:mi:ss’))*24*60)) rows_per_minute
from sys.v_$sqlarea
where sql_text like ‘insert %into “%’ and command_type = 2 and open_versions > 0;
Database SGA Report:
Monitor SGA Information:
SELECT SUM(VALUE)/1024/1024 “Size in MB” from SYS.v_$sga;
select NAME, BYTES from v$sgastat order by NAME;
Monitor Shared Pool Information:
select to_number(value) shared_pool_size, sum_obj_size, sum_sql_size, sum_user_size,
(sum_obj_size + sum_sql_size+sum_user_size)* 1.3 min_shared_pool
from (select sum(sharable_mem) sum_obj_size
from v$db_object_cache where type ‘CURSOR’),
(select sum(sharable_mem) sum_sql_size from v$sqlarea),
(select sum(250 * users_opening) sum_user_size from v$sqlarea), v$parameter
where name = ‘shared_pool_size’;
Monitor PGA Information:
Select st.sid “SID”, sn.name “TYPE”, ceil(st.value / 1024 / 1024/1024) “GB”
from v$sesstat st, v$statname sn where st.statistic# = sn.statistic#
and sid in (select sid from v$session where username like UPPER(‘hrms’))
and upper(sn.name) like ‘%PGA%’ order by st.sid, st.value desc;
Monitor CPU Usage Information:
select ss.username, se.SID, VALUE/100 cpu_usage_seconds
from v$session ss, v$sesstat se, v$statname sn where se.STATISTIC# = sn.STATISTIC#
and NAME like ‘%CPU used by this session%’ and se.SID = ss.SID
and ss.status=’ACTIVE’ and ss.username is not null order by VALUE desc;
Disk I/O Report:
WITH totreadwrite AS (SELECT SUM (phyrds) phys_reads, SUM (phywrts) phys_wrts FROM v$filestat)
SELECT NAME, phyrds, phyrds * 100 / trw.phys_reads read_pct,
phywrts, phywrts * 100 / trw.phys_wrts write_pct
FROM totreadwrite trw, v$datafile df, v$filestat fs
WHERE df.file# = fs.file# ORDER BY phyrds DESC;
IO Usage for a Query:
select b.sql_text “Statement “, a.Disk_reads “Disk Reads”, a.executions “Executions”,
a.disk_reads/decode(a.executions,0,1,a.executions) “Ratio”,c.username
from v$sqlarea a, v$sqltext_with_newlines b,dba_users c
where a.parsing_user_id = c.user_id and a.address=b.address and a.disk_reads>100000
order by a.disk_reads desc,b.piece;
Display the System write batch size:
SELECT kviival write_batch_size
FROM x$kvii
WHERE kviidsc = ‘DB writer IO clump’ OR kviitag = ‘kcbswc’
Monitor Disk I/O Contention:
select NAME, PHYRDS “Physical Reads”,
round((PHYRDS / PD.PHYS_READS)*100,2) “Read %”, PHYWRTS “Physical Writes”,
round(PHYWRTS * 100 / PD.PHYS_WRTS,2) “Write %”,
fs.PHYBLKRD+FS.PHYBLKWRT “Total Block I/O’s” from ( select
sum(PHYRDS) PHYS_READS, sum(PHYWRTS) PHYS_WRTS
from v$filestat ) pd, v$datafile df, v$filestat fs
where df.FILE# = fs.FILE#
order by fs.PHYBLKRD+fs.PHYBLKWRT desc;
DB Locks/Blocks/Blocker Details:
Track Block session in oracle 9i/10g
select s1.username || ‘@’ || s1.machine || ‘ ( SID=’ || s1.sid || ‘ )
is blocking ‘ || s2.username || ‘@’ || s2.machine || ‘ ( SID=’ ||
s2.sid || ‘ ) ‘ AS blocking_status from gv$lock l1, gv$session s1,
gv$lock l2, gv$session s2 where s1.sid = l1.sid and s2.sid = l2.sid and
l1.BLOCK = 1 and l2.request > 0 and l1.id1 = l2.id1 and l2.id2 =
l2.id2;
select do.object_name, row_wait_obj#, row_wait_file#, row_wait_block#, row_wait_row#,
dbms_rowid.rowid_create(1, ROW_WAIT_OBJ#, ROW_WAIT_FILE#, ROW_WAIT_BLOCK#, ROW_WAIT_ROW#)
from gv$session s, dba_objects do
where sid = 543 and s.ROW_WAIT_OBJ# = do.OBJECT_ID;
For detail description of blocking you can run this on your Oracle-Home
oracle-home\rdbms\admin\utllockt.sql
Select process,sid, blocking_session from v$session where blocking_session is not null; –in 10g
Track Locked Session & Blocked:
PROMPT Blocked and Blocker Sessions
select /*+ ORDERED */ blocker.sid blocker_sid, blocked.sid blocked_sid ,
TRUNC(blocked.ctime/60) min_blocked, blocked.request
from (select *from v$lock
where block != 0 and type = ‘TX’) blocker, v$lock blocked
where blocked.type=’TX’ and blocked.block = 0 and blocked.id1 = blocker.id1;
Track Database Lock:
Select /*+ ORDERED */ l.sid, l.lmode,
TRUNC(l.ctime/60) min_blocked, u.name||’.'||o.NAME blocked_obj
from (select * from v$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#;
Track the Session Waiting for Lock:
SELECT holding_session bsession_id, waiting_session wsession_id,
b.username busername, a.username wusername, c.lock_type TYPE, mode_held,
mode_requested, lock_id1, lock_id2
FROM sys.v_$session b, sys.dba_waiters c, sys.v_$session a
WHERE c.holding_session = b.sid AND c.waiting_session = a.sid;
Track Blocker Details:
SELECT sid, serial#, username, osuser, machine
FROM v$session
WHERE sid IN (select sid from v$lock
where block != 0 and type = ‘TX’);
Users/Sessions/Processes Details:
Average Wait Time for Particular Event:
SELECT EVENT, TOTAL_WAITS, TOTAL_TIMEOUTS, TIME_WAITED, round(AVERAGE_WAIT,2) “Average Wait”
from v$system_event order by TOTAL_WAITS;
Sessions Waiting On A Particular Wait Event:
SELECT count(*), event
FROM v$session_wait
WHERE wait_time = 0 AND event NOT IN (‘smon timer’,'pipe get’,'wakeup
time manager’, ‘pmon timer’,'rdbms ipc message’, ‘SQL*Net message from
client’)
GROUP BY event ORDER BY 1 DESC;
Track Logon time of DB user and OS user:
Select to_char(logon_time,’dd/mm/yyyy hh24:mi:ss’),osuser,status,schemaname,machine from v$session where type !=’BACKGROUND’;
Track all Session User Details:
select sid, serial#,machine, status, osuser,username from v$session where username!=’NULL’;
Track Active Session User Details:
SELECT SID, Serial#, UserName, Status, SchemaName, Logon_Time FROM V$Session WHERE Status= ‘ACTIVE’ AND UserName IS NOT NULL;
Track Active User Details:
SELECT s.inst_id, s.sid, s.serial#, p.spid, s.username, s.program
FROM gv$session s JOIN gv$process p ON p.addr = s.paddr AND p.inst_id =
s.inst_id WHERE s.type != ‘BACKGROUND’;
Report OS Process ID for each session:
SELECT ses.username || ‘(‘ || ses.sid || ‘)’ users, acc.owner owner, acc.OBJECT OBJECT, ses.lockwait, prc.spid os_process
FROM v$process prc, v$access acc, v$session ses
WHERE prc.addr = ses.paddr AND ses.sid = acc.sid;
Show Username and SID/SPID with Program Name:
select sid,name,value from v$spparameter where isspecified=’TRUE’;
SELECT SID, Serial#, UserName, Status, SchemaName, Logon_Time FROM V$Session
WHERE Status= ‘ACTIVE’ AND UserName IS NOT NULL; –to find active session
SELECT s.inst_id, s.sid, s.serial#, p.spid, s.username, s.program –active users details
FROM gv$session s JOIN gv$process p ON p.addr = s.paddr AND p.inst_id = s.inst_id
WHERE s.type != ‘BACKGROUND’;
Track Current Transaction in Database:
select a.sid, a.username, b.xidusn, b.used_urec, b.used_ublk from v$session a, v$transaction b
where a.saddr = b.ses_addr;
Important Object Information:
Database Object Information:
Select owner,object_type,count(*) from dba_objects Where owner not IN
(‘SYS’,'MDSYS’,'CTXSYS’,'HR’,'ORDSYS’,'OE’,'ODM_MTR’,'WMSYS’,'XDB’,'QS_WS’,
‘RMAN’,'SCOTT’,'QS_ADM’,'QS_CBADM’,
‘ORDSYS’,'OUTLN’,'PM’,'QS_OS’,'QS_ES’,'ODM’,'OLAPSYS’,'WKSYS’,'SH’,'SYSTEM’,'ORDPLUGINS’,'QS’,'QS_CS’)
Group by owner,object_type order by owner;
Query to Find 5 largest object in Database:
SELECT * FROM (select SEGMENT_NAME, SEGMENT_TYPE, BYTES/1024/1024/1024
GB, TABLESPACE_NAME from dba_segments order by 3 desc ) WHERE ROWNUM =
sysdate – 7
Track Mviews Not Refreshed since last Week:
Select mview_name from user_mviews where LAST_REFRESH_DATE < sysdate – 7;
