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 – Latch Contention (top 5 latches)

This script will display the top 5 latches with the most sleeps.

Script can be changed to even sort the display on misses instead.

set linesize 120
col name format a30

select * from
 (select name, gets,misses,  sleeps
 from   v$latch
 order by sleeps desc)
 where rownum < 6;

Script – Top SQL (Physical Reads)

This script will list the top 5 SQL statements sorted by the most number of physical reads

set serverout on size 1000000

set feedback off

declare

top5 number;

text1 varchar2(4000);

x number;

len1 number;

Cursor c1 is

select disk_reads,substr(sql_text,1,4000)

from v$sqlarea

order by disk_reads desc;

begin

dbms_output.put_line('Reads'||'  '||'                          Text');

dbms_output.put_line ('-----'||'  '||'----------------------------------------------------');

dbms_output.put_line('      ');

open c1;

for i in 1 .. 5 loop

fetch c1 into top5, text1;

dbms_output.put_line(rpad(to_char(top5),9)|| ' '||substr(text1,1,66));

len1 :=length(text1);

x := 66;

while len1 > x-1 loop

dbms_output.put_line('"         '||substr(text1,x,64));

x := x+64;

end loop;

end loop;

end;

/

Script – Top SQL (Buffer Gets)

This script will list the top 5 SQL statements sorted by the most number of buffer gets or logical reads

set serverout on size 1000000

declare
top5 number;
text1 varchar2(4000);
x number;
len1 number;
Cursor c1 is
select buffer_gets,substr(sql_text,1,4000)
from v$sqlarea
order by buffer_gets desc;
begin
dbms_output.put_line('Reads'||'  '||'                          Text');
dbms_output.put_line ('-----'||'  '||'---------------------------------------------------');
dbms_output.put_line('      ');
open c1;
for i in 1 .. 5 loop
fetch c1 into top5, text1;
dbms_output.put_line(rpad(to_char(top5),9)|| ' '||substr(text1,1,66));
len1 :=length(text1);
x := 66;
while len1 > x-1 loop
dbms_output.put_line('"         '||substr(text1,x,64));
x := x+64;
end loop;
end loop;
end;
/

Script – Segments with highest I/O activity

This script will list the top 10 segments in the database that have the most number of
physical reads against them.
Script can also be changed to query on 'physical writes' instead.

set pagesize 200
setlinesize 120
col segment_name format a20
col owner format a10 

select segment_name,object_type,total_physical_reads
from ( select owner||'.'||object_name as segment_name,object_type,
value as total_physical_reads
from v$segment_statistics
where statistic_name in ('physical reads')
order by total_physical_reads desc)
where rownum <=10;

Script – What Wait Events Are Sessions Waiting On

set linesize 120
col username format a10
col event format a30
 
select sid, serial#,username, event,
seconds_in_wait, wait_time
from v$session where state = 'WAITING'
and wait_class != 'Idle'
order by event
;

Script – 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;

Script – Datafiles with highest I/O activity

col name format a40
set linesize 140
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 <6;