Useful DBA Scripts

Script – Check RMAN Backup Status

Scripts to check backup status and timings of database backups –

This script will be run in the database, not the catalog.

This script will report on all backups – full, incremental and archivelog backups –

col STATUS format a9
col hrs format 999.99
select
SESSION_KEY, INPUT_TYPE, STATUS,
to_char(START_TIME,'mm/dd/yy hh24:mi') start_time,
to_char(END_TIME,'mm/dd/yy hh24:mi')   end_time,
elapsed_seconds/3600                   hrs
from V$RMAN_BACKUP_JOB_DETAILS
order by session_key;

This script will report all on full and incremental backups, not archivelog backups –

col STATUS format a9
col hrs format 999.99
select
SESSION_KEY, INPUT_TYPE, STATUS,
to_char(START_TIME,'mm/dd/yy hh24:mi') start_time,
to_char(END_TIME,'mm/dd/yy hh24:mi')   end_time,
elapsed_seconds/3600                   hrs
from V$RMAN_BACKUP_JOB_DETAILS
where input_type='DB INCR'
order by session_key;

Script – Sessions with high physical reads

 set linesize 120
col os_user format a10
col username format a15

col pid format 9999999999
PROMPT SESSIONS SORTED BY PHYSICAL READS
PROMPT
select
  OSUSER os_user,username,
    PROCESS pid,
    ses.SID sid,
    SERIAL#,
    PHYSICAL_READS,
     BLOCK_CHANGES
 from       v$session ses,
   v$sess_io sio
  where      ses.SID = sio.SID
and username is not null
and status='ACTIVE'
 order      by PHYSICAL_READS;

Script – Database structure and file location

set pagesize 500
set linesize 130
Prompt
Prompt Control Files Location >>>>
col name  format a60 heading "Control Files"

select name
from   sys.v_$controlfile
/

Prompt
Prompt Redo Log File Locations >>>>
Prompt

col Grp    format 9999
col member format a50 heading "Online REDO Logs"
col File#  format 9999
col name   format a50 heading "Online REDO Logs"
break on Grp
select group#,member
from   sys.v_$logfile
/


Prompt Data Files Locations >>>>

col Tspace    format a25
col status    format a3  heading Sta
col Id        format 9999
col Mbyte     format 999999999
col name      format a50 heading "Database Data Files"
col Reads     format 99,999,999
col Writes    format 99,999,999

break on report
compute sum label 'Total(MB)'  of Mbyte  on report

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;




Control Files Location >>>>

Control Files
------------------------------------------------------------
/u03/oradata/rcatp/control01.ctl
/u05/oradata/rcatp/control02.ctl


Redo Log File Locations >>>>


    GROUP# Online REDO Logs
---------- --------------------------------------------------
         1 /u03/oradata/rcatp/redo01.log
         2 /u05/oradata/rcatp/redo02.log
         3 /u03/oradata/rcatp/redo03.log
         3 /u05/oradata/rcatp/redo03b.log
         1 /u05/oradata/rcatp/redo01b.log
         2 /u03/oradata/rcatp/redo02b.log

6 rows selected.

Data Files Locations >>>>

   ID Database Data Files                                     MBYTE Sta TSPACE
----- -------------------------------------------------- ---------- --- -------------------------
    9 /u03/oradata/rcatp/patrol01.dbf                            20 OK  PATROL
    7 /u03/oradata/rcatp/rman10p01.dbf                          466 OK  RMAN10P
    5 /u03/oradata/rcatp/rman11p01.dbf                          200 OK  RMAN11P
    8 /u03/oradata/rcatp/rman9p01.dbf                           106 OK  RMAN9P
    3 /u03/oradata/rcatp/sysaux01.dbf                           540 OK  SYSAUX
    1 /u03/oradata/rcatp/system01.dbf                           700 OK  SYSTEM
    2 /u03/oradata/rcatp/undotbs01.dbf                          220 OK  UNDOTBS1
    4 /u03/oradata/rcatp/users01.dbf                              6 OK  USERS
                                                         ----------
sum                                                            2258

8 rows selected.

ASH and AWR Performance Tuning Scripts

Listed below are some SQL queries which I find particularly useful for performance tuning. These are based on the Active Session History V$ View to get a current perspective of performance and the DBA_HIST_* AWR history tables for obtaining performance data pertaining to a period of time in the past.

Top Recent Wait Events

col EVENT format a60 

select * from (
select active_session_history.event,
sum(active_session_history.wait_time +
active_session_history.time_waited) ttl_wait_time
from v$active_session_history active_session_history
where active_session_history.event is not null
group by active_session_history.event
order by 2 desc)
where rownum < 6
/

Top Wait Events Since Instance Startup

col event format a60

select event, total_waits, time_waited
from v$system_event e, v$event_name n
where n.event_id = e.event_id
and n.wait_class !='Idle'
and n.wait_class = (select wait_class from v$session_wait_class
 where wait_class !='Idle'
 group by wait_class having
sum(time_waited) = (select max(sum(time_waited)) from v$session_wait_class
where wait_class !='Idle'
group by (wait_class)))
order by 3;

List Of Users Currently Waiting

col username format a12
col sid format 9999
col state format a15
col event format a50
col wait_time format 99999999
set pagesize 100
set linesize 120

select s.sid, s.username, se.event, se.state, se.wait_time
from v$session s, v$session_wait se
where s.sid=se.sid
and se.event not like 'SQL*Net%'
and se.event not like '%rdbms%'
and s.username is not null
order by se.wait_time;

Find The Main Database Wait Events In A Particular Time Interval

First determine the snapshot id values for the period in question.

In this example we need to find the SNAP_ID for the period 10 PM to 11 PM on the 14th of November, 2012.

select snap_id,begin_interval_time,end_interval_time
from dba_hist_snapshot
where to_char(begin_interval_time,'DD-MON-YYYY')='14-NOV-2012'
and EXTRACT(HOUR FROM begin_interval_time) between 22 and 23;

set verify off
select * from (
select active_session_history.event,
sum(active_session_history.wait_time +
active_session_history.time_waited) ttl_wait_time
from dba_hist_active_sess_history active_session_history
where event is not null
and SNAP_ID between &ssnapid and &esnapid
group by active_session_history.event
order by 2 desc)
where rownum

Top CPU Consuming SQL During A Certain Time Period

Note – in this case we are finding the Top 5 CPU intensive SQL statements executed between 9.00 AM and 11.00 AM

select * from (
select
SQL_ID,
 sum(CPU_TIME_DELTA),
sum(DISK_READS_DELTA),
count(*)
from
DBA_HIST_SQLSTAT a, dba_hist_snapshot s
where
s.snap_id = a.snap_id
and s.begin_interval_time > sysdate -1
and EXTRACT(HOUR FROM S.END_INTERVAL_TIME) between 9 and 11
group by
SQL_ID
order by
sum(CPU_TIME_DELTA) desc)
where rownum

Which Database Objects Experienced the Most Number of Waits in the Past One Hour

set linesize 120
col event format a40
col object_name format a40

select * from 
(
  select dba_objects.object_name,
 dba_objects.object_type,
active_session_history.event,
 sum(active_session_history.wait_time +
  active_session_history.time_waited) ttl_wait_time
from v$active_session_history active_session_history,
    dba_objects
 where 
active_session_history.sample_time between sysdate - 1/24 and sysdate
and active_session_history.current_obj# = dba_objects.object_id
 group by dba_objects.object_name, dba_objects.object_type, active_session_history.event
 order by 4 desc)
where rownum < 6;

Top 5 SQL statements in the past one hour

select * from (
select active_session_history.sql_id,
 dba_users.username,
 sqlarea.sql_text,
sum(active_session_history.wait_time +
active_session_history.time_waited) ttl_wait_time
from v$active_session_history active_session_history,
v$sqlarea sqlarea,
 dba_users
where 
active_session_history.sample_time between sysdate -  1/24  and sysdate
  and active_session_history.sql_id = sqlarea.sql_id
and active_session_history.user_id = dba_users.user_id
 group by active_session_history.sql_id,sqlarea.sql_text, dba_users.username
 order by 4 desc )
where rownum

SQL with the highest I/O in the past one day

select * from 
(
SELECT /*+LEADING(x h) USE_NL(h)*/ 
       h.sql_id
,      SUM(10) ash_secs
FROM   dba_hist_snapshot x
,      dba_hist_active_sess_history h
WHERE   x.begin_interval_time > sysdate -1
AND    h.SNAP_id = X.SNAP_id
AND    h.dbid = x.dbid
AND    h.instance_number = x.instance_number
AND    h.event in  ('db file sequential read','db file scattered read')
GROUP BY h.sql_id
ORDER BY ash_secs desc )
where rownum

Top CPU consuming queries since past one day

select * from (
select 
	SQL_ID, 
	sum(CPU_TIME_DELTA), 
	sum(DISK_READS_DELTA),
	count(*)
from 
	DBA_HIST_SQLSTAT a, dba_hist_snapshot s
where
 s.snap_id = a.snap_id
 and s.begin_interval_time > sysdate -1
	group by 
	SQL_ID
order by 
	sum(CPU_TIME_DELTA) desc)
where rownum

Find what the top SQL was at a particular reported time of day

First determine the snapshot id values for the period in question.

In thos example we need to find the SNAP_ID for the period 10 PM to 11 PM on the 14th of November, 2012.

select snap_id,begin_interval_time,end_interval_time
from dba_hist_snapshot
where to_char(begin_interval_time,'DD-MON-YYYY')='14-NOV-2012'
and EXTRACT(HOUR FROM begin_interval_time) between 22 and 23;

select * from
 (
select
 sql.sql_id c1,
sql.buffer_gets_delta c2,
sql.disk_reads_delta c3,
sql.iowait_delta c4
 from
dba_hist_sqlstat sql,
dba_hist_snapshot s
 where
 s.snap_id = sql.snap_id
and
 s.snap_id= &snapid
 order by
 c3 desc)
 where rownum < 6 
/

Analyse a particular SQL ID and see the trends for the past day

select
 s.snap_id,
 to_char(s.begin_interval_time,'HH24:MI') c1,
 sql.executions_delta c2,
 sql.buffer_gets_delta c3,
 sql.disk_reads_delta c4,
 sql.iowait_delta c5,
sql.cpu_time_delta c6,
 sql.elapsed_time_delta c7
 from
 dba_hist_sqlstat sql,
 dba_hist_snapshot s
 where
 s.snap_id = sql.snap_id
 and s.begin_interval_time > sysdate -1
 and
sql.sql_id='&sqlid'
 order by c7
 /

Do we have multiple plan hash values for the same SQL ID – in that case may be changed plan is causing bad performance

select 
  SQL_ID 
, PLAN_HASH_VALUE 
, sum(EXECUTIONS_DELTA) EXECUTIONS
, sum(ROWS_PROCESSED_DELTA) CROWS
, trunc(sum(CPU_TIME_DELTA)/1000000/60) CPU_MINS
, trunc(sum(ELAPSED_TIME_DELTA)/1000000/60)  ELA_MINS
from DBA_HIST_SQLSTAT 
where SQL_ID in (
'&sqlid') 
group by SQL_ID , PLAN_HASH_VALUE
order by SQL_ID, CPU_MINS;

Top 5 Queries for past week based on ADDM recommendations

/*
Top 10 SQL_ID's for the last 7 days as identified by ADDM
from DBA_ADVISOR_RECOMMENDATIONS and dba_advisor_log
*/

col SQL_ID form a16
col Benefit form 9999999999999
select * from (
select b.ATTR1 as SQL_ID, max(a.BENEFIT) as "Benefit" 
from DBA_ADVISOR_RECOMMENDATIONS a, DBA_ADVISOR_OBJECTS b 
where a.REC_ID = b.OBJECT_ID
and a.TASK_ID = b.TASK_ID
and a.TASK_ID in (select distinct b.task_id
from dba_hist_snapshot a, dba_advisor_tasks b, dba_advisor_log l
where a.begin_interval_time > sysdate - 7 
and  a.dbid = (select dbid from v$database) 
and a.INSTANCE_NUMBER = (select INSTANCE_NUMBER from v$instance) 
and to_char(a.begin_interval_time, 'yyyymmddHH24') = to_char(b.created, 'yyyymmddHH24') 
and b.advisor_name = 'ADDM' 
and b.task_id = l.task_id 
and l.status = 'COMPLETED') 
and length(b.ATTR4) > 1 group by b.ATTR1
order by max(a.BENEFIT) desc) where rownum < 6;

Blog for DBA Consultants

Thursday, December 1, 2022

Useful Oracle DBA Scripts