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1. ASH – Active Session History
Feel the Power
Kyle Hailey
http://perfvision.com

2. #.2
Copyright 2006 Kyle Hailey
ASH
Whole New Paradigm in
Technology
The Power of ASH lies in
Simplifying Performance Tuning
 Totally new and exciting methodology
 Cheaper, Quicker, Richer and better tasting too

3. #.3
Copyright 2006 Kyle Hailey
Why should you care?
Because ASH can Change your life …
 10g immediately Accessible
 Geeks: Via scripts in SQL (?/rdbms/admin/ashrpt.sql)
 Managers : Graphical OEM 10g
 Stuck on Oracle 7,8,9 ?
… my apologies because 10g rocks, but …
no worries, the data is accessible for you too via scripts
http://perfvision.com/sash.php

4. #.4
Copyright 2006 Kyle Hailey
ASH uses Sampling
New Paradigm
 Clear Vision of the future
 Use new sampling technology
 Lets go of the need to know 100%
 Statistical approximation
 Cheaper
 Richer Multidimensional Data
 Much more powerful, identifies
 SQL
 Sessions
 Objects
 Machine
 User

5. #.5
Copyright 2006 Kyle Hailey
To identify Players before ASH
 Sessions
 # sessions x (# wait events + statistics)
 Example (150 x (800+200) = 150,000 )
 SQL
 v$sql
 Could be 10000s
 Takes out latches that compete with other sql executions
 Objects
 V$segstat 9i+
 Could be 1000s of objects
Expensive !

6. #.6
Copyright 2006 Kyle Hailey
ASH – Intelligence for the new
Millennium
 Intelligently Collects Data
 It self adjusts for your needs
 More activity, more data collected
 Less activity, less data collected
 Those old methods collected everything
 Obfuscated the problem, too many statistics too late
 Costly
 Too Granular – once an hour ?! Give me a break

7. ASH Samples Session State
TIME
?
? ?
? ?
? ?
? ?
?
Sessions change a lot quicker but can get the main
picture via sampling by sampling faster
Every second
Every second
10:00:00 10:00:01 10:00:02 10:00:03 10:00:04 10:00:05

8. #.8
Copyright 2006 Kyle Hailey
Sampling is like taking
Pictures

9. #.9
Copyright 2006 Kyle Hailey
If happens a lot or for long …
we’ll catch it, guaranteed
• Long running queries easily found
Long running queries easily found
• Short high execution queries found most of the time
Short high execution queries found most of the time
• Short low execution queries rarely found
Short low execution queries rarely found
Produces a good representation of load on DB
Produces a good representation of load on DB

10. #.10
Copyright 2006 Kyle Hailey
Session States
IO CPU Idle
Wait
Work
Work
Latency
Latency
Contention
Contention

11. #.11
Copyright 2006 Kyle Hailey
IDLE
 Example : SQL*Net Message from Client
 10g
 9i or below – just have to keep track
 Statspack STATS$IDLE_EVENT
select name
from v$event_name
where wait_class='Idle';
58 Rows

12. #.12
Copyright 2006 Kyle Hailey
CPU
 ASH: SESSION_STATE = “ON CPU”
 ASH: wait_time > 0
10g: v$session
9i: v$session_wait
w.wait_time != 0 /* on CPU */ and
s.status='ACTIVE' /* ACTIVE */
Identifying CPU via v$session_wait is
Identifying CPU via v$session_wait is
a huge break through
a huge break through

13. #.13
Copyright 2006 Kyle Hailey
IO
 ASH: SESSION_STATE=‘WAITING’
&
 10g: WAIT_CLASS=‘User I/O’
 9i:
 Look at 10g for ideas
 db file sequential read
 db file scattered read
 db file parallel read
 direct path read

14. #.14
Copyright 2006 Kyle Hailey
WAITING
 ASH: SESSION_STATE=‘WAITING’
 ASH: WAIT_TIME <= 0
 WAIT_CLASS
1. Administrative
2. Application
3. Cluster
4. Commit
5. Concurrency
6. Configuration
7. Network
8. Other
9. Scheduler
10. System I/O
 800+ WAIT

15. Session 1
Session 2
Session 3
Session 4
TIME
Samples for all users
10:15:00 10:15:01 10:15:02 10:15:03 10:15:04 10:15:05 10:15:06 10:15:07

16. #.16
Copyright 2006 Kyle Hailey
v$active_session_history
SESSION_ID NUMBER
SESSION_SERIAL# NUMBER
USER_ID NUMBER
SERVICE_HASH NUMBER
SESSION_TYPE VARCHAR2(10)
PROGRAM VARCHAR2(64)
MODULE VARCHAR2(48)
ACTION VARCHAR2(32)
CLIENT_ID VARCHAR2(64)
EVENT VARCHAR2(64)
EVENT_ID NUMBER
EVENT# NUMBER
SEQ# NUMBER
P1 NUMBER
P2 NUMBER
P3 NUMBER
WAIT_TIME NUMBER
TIME_WAITED NUMBER
CURRENT_OBJ# NUMBER
CURRENT_FILE# NUMBER
CURRENT_BLOCK# NUMBER0
SQL_ID VARCHAR2(13)
SQL_CHILD_NUMBER NUMBER
SQL_PLAN_HASH_VALUE NUMBER
SQL_OPCODE NUMBER
QC_SESSION_ID NUMBER
QC_INSTANCE_ID NUMBER
SAMPLE_ID NUMBER
SAMPLE_TIME TIMESTAMP(3) When
Session
SQL
Wait
SESSION_STATE VARCHAR2(7)
WAIT_TIME NUMBER
State
TIME_WAITED NUMBER
Duration

17. #.17
Copyright 2006 Kyle Hailey
Groupings – Top Consumer
SESSION_ID
SESSION_SERIAL# (signal SID reuse)
SESSION_TYPE (FOREGROUND,BACKGROUND)
CURRENT_OBJ#
CURRENT_FILE#
CURRENT_BLOCK#
USER_ID (SYS, SYSTEM, SCOTT etc)
SERVICE_HASH (OE,GL,HR)
PROGRAM (SQL, JDBC, Forms etc)
MODULE.ACTION(PLSQL tagging)
CLIENT_ID (identifying users in a session pool)
SQL_ID
QC_SESSION_ID - Query Coordinator
QC_INSTANCE_ID – RAC
EVENT + P1, P2, P3

18. #.18
Copyright 2006 Kyle Hailey
Amazing things YOU can do with
ASH
Consumers
 Top Session
 Top User
 Top SQL
 Top Object
 Top Module.Action
 Top Program
 Top Service
 Top Client
 Top Wait
No machine  - collect on logon trigger
X
Resources
• CPU
• Waits
• Event (800*)
• I/O
• File
• Block
• Time
Find top consumers by resource usage

19. #.19
Copyright 2006 Kyle Hailey
Select
session_id,
count(*)
from
v$active_session_history
where
session_state= ‘ON CPU‘ and
SAMPLE_TIME > sysdate – (5/(24*60))
group by
session_id
order by
count(*) desc;
Select
session_id,
count(*)
from
v$active_session_history
where
session_state= ‘ON CPU‘ and
SAMPLE_TIME > sysdate – (5/(24*60))
group by
session_id
order by
count(*) desc;
Top CPU Session
Who is the rogue session ?

20. #.20
Copyright 2006 Kyle Hailey
Results Top CPU Session
SESSION_ID COUNT(*)
---------- ----------
265 256
264 15
257 12
271 12
276 1
SESSION_ID COUNT(*)
---------- ----------
265 256
264 15
257 12
271 12
276 1
SESSION_ID COUNT(*)
---------- ----------
265 256
264 15
257 12
271 12
276 1

21. #.21
Copyright 2006 Kyle Hailey
CPU with Bars
SESSION_ID COUNT(*) % Bar
---------- ---------- ---------- ------------
257 75 25 |*** |
263 62 21 |** |
256 32 11 |* |
264 9 3 | |
277 3 1 | |
258 1 0 | |
280 1 0 | |
SESSION_ID COUNT(*) % Bar
---------- ---------- ---------- ------------
257 75 25 |*** |
263 62 21 |** |
256 32 11 |* |
264 9 3 | |
277 3 1 | |
258 1 0 | |
280 1 0 | |
Bar shows 10% increments
Bar shows 10% increments

22. #.22
Copyright 2006 Kyle Hailey
Select
session_id,
count(*)
from
v$active_session_history
where
session_state=‘WAITING’ and
SAMPLE_TIME > SYSDATE - (5/(24*60))
group by
session_id
order by
count(*) desc;
Select
session_id,
count(*)
from
v$active_session_history
where
session_state=‘WAITING’ and
SAMPLE_TIME > SYSDATE - (5/(24*60))
group by
session_id
order by
count(*) desc;
Top Waiting Session
 Top Waiting Session in last 5 minutes

23. #.23
Copyright 2006 Kyle Hailey
SESSION_ID COUNT(*)
---------- ----------
272 224
254 8
249 5
276 5
277 4
270 1
SESSION_ID COUNT(*)
---------- ----------
272 224
254 8
249 5
276 5
277 4
270 1
Top Waiting Session Results

24. #.24
Copyright 2006 Kyle Hailey
Top SQL from ASH
select
ash.SQL_ID ,
sum(decode(ash.session_state,'ON CPU',1,0)) "CPU",
sum(decode(ash.session_state,'WAITING',1,0)) -
sum(decode(ash.session_state,'WAITING', decode(en.wait_class, 'User I/O',1,0),0)) "WAIT" ,
sum(decode(ash.session_state,'WAITING', decode(en.wait_class, 'User I/O',1,0),0)) "IO" ,
sum(decode(ash.session_state,'ON CPU',1,1)) "TOTAL"
from v$active_session_history ash,
v$event_name en
where SQL_ID is not NULL and en.event#=ash.event#
group by sql_id
order by sum(decode(session_state,'ON CPU',1,1)) desc
select
ash.SQL_ID ,
sum(decode(ash.session_state,'ON CPU',1,0)) "CPU",
sum(decode(ash.session_state,'WAITING',1,0)) -
sum(decode(ash.session_state,'WAITING', decode(en.wait_class, 'User I/O',1,0),0)) "WAIT" ,
sum(decode(ash.session_state,'WAITING', decode(en.wait_class, 'User I/O',1,0),0)) "IO" ,
sum(decode(ash.session_state,'ON CPU',1,1)) "TOTAL"
from v$active_session_history ash,
v$event_name en
where SQL_ID is not NULL and en.event#=ash.event#
group by sql_id
order by sum(decode(session_state,'ON CPU',1,1)) desc

25. #.25
Copyright 2006 Kyle Hailey
Top SQL from ASH Results
SQL_ID CPU WAITING IO TOTAL
------------- ---------- ---------- ---------- ----------
4c1xvq9ufwcjc 23386 0 0 23386
6wjw6rz5uvbp3 99 0 23 122
968dm8hr9qd03 97 0 22 119
938jp5gasmrah 90 0 25 115
cv8xnv81kf582 42 0 9 51
6p9bzu19v965k 21 0 0 21
5zu8pxnun66bu 15 0 0 15
db2jr13nup72v 9 0 0 9
7ks5gnj38hghv 8 0 0 8
SQL_ID CPU WAITING IO TOTAL
------------- ---------- ---------- ---------- ----------
4c1xvq9ufwcjc 23386 0 0 23386
6wjw6rz5uvbp3 99 0 23 122
968dm8hr9qd03 97 0 22 119
938jp5gasmrah 90 0 25 115
cv8xnv81kf582 42 0 9 51
6p9bzu19v965k 21 0 0 21
5zu8pxnun66bu 15 0 0 15
db2jr13nup72v 9 0 0 9
7ks5gnj38hghv 8 0 0 8

26. #.26
Copyright 2006 Kyle Hailey
Top Session
select
ash.session_id,
ash.session_serial#,
ash.user_id,
ash.program,
sum(decode(ash.session_state,'ON CPU',1,0)) "CPU",
sum(decode(ash.session_state,'WAITING',1,0)) -
sum(decode(ash.session_state,'WAITING',
decode(en.wait_class,'User I/O',1, 0 ), 0)) "WAITING" ,
sum(decode(ash.session_state,'WAITING',
decode(en.wait_class,'User I/O',1, 0 ), 0)) "IO" ,
sum(decode(session_state,'ON CPU',1,1)) "TOTAL"
from v$active_session_history ash,
v$event_name en
where en.event# = ash.event#
group by session_id,user_id,session_serial#,program
order by sum(decode(session_state,'ON CPU',1,1))
select
ash.session_id,
ash.session_serial#,
ash.user_id,
ash.program,
sum(decode(ash.session_state,'ON CPU',1,0)) "CPU",
sum(decode(ash.session_state,'WAITING',1,0)) -
sum(decode(ash.session_state,'WAITING',
decode(en.wait_class,'User I/O',1, 0 ), 0)) "WAITING" ,
sum(decode(ash.session_state,'WAITING',
decode(en.wait_class,'User I/O',1, 0 ), 0)) "IO" ,
sum(decode(session_state,'ON CPU',1,1)) "TOTAL"
from v$active_session_history ash,
v$event_name en
where en.event# = ash.event#
group by session_id,user_id,session_serial#,program
order by sum(decode(session_state,'ON CPU',1,1))
select
ash.session_id,
ash.session_serial#,
ash.user_id,
ash.program,
sum(decode(ash.session_state,'ON CPU',1,0)) "CPU",
sum(decode(ash.session_state,'WAITING',1,0)) -
sum(decode(ash.session_state,'WAITING',
decode(en.wait_class,'User I/O',1, 0 ), 0)) "WAITING" ,
sum(decode(ash.session_state,'WAITING',
decode(en.wait_class,'User I/O',1, 0 ), 0)) "IO" ,
sum(decode(session_state,'ON CPU',1,1)) "TOTAL"
from v$active_session_history ash,
v$event_name en
where en.event# = ash.event#
group by session_id,user_id,session_serial#,program
order by sum(decode(session_state,'ON CPU',1,1))

27. #.27
Copyright 2006 Kyle Hailey
Top Session Results
SESSION_ID SERIAL# USER_ID PROGRAM CPU WAITING IO
---------- ------- ---------- ------------------------- ------- ---------- ----------
247 61970 1 sqlplus 11698 0 0
277 1 0 oracle@labsfrh903 (LGWR) 14 21 0
276 1 0 oracle@labsfrh903 (CKPT) 19 10 0
278 1 0 oracle@labsfrh903 (DBW0) 29 0 0
280 1 0 oracle@labsfrh903 (PMON) 19 0 0
254 22617 5 Executor.exe 13 0 3
255 12877 5 Executor.exe 11 0 5
257 33729 5 Executor.exe 15 0 1
255 13417 5 Executor.exe 14 0 2
SESSION_ID SERIAL# USER_ID PROGRAM CPU WAITING IO
---------- ------- ---------- ------------------------- ------- ---------- ----------
247 61970 1 sqlplus 11698 0 0
277 1 0 oracle@labsfrh903 (LGWR) 14 21 0
276 1 0 oracle@labsfrh903 (CKPT) 19 10 0
278 1 0 oracle@labsfrh903 (DBW0) 29 0 0
280 1 0 oracle@labsfrh903 (PMON) 19 0 0
254 22617 5 Executor.exe 13 0 3
255 12877 5 Executor.exe 11 0 5
257 33729 5 Executor.exe 15 0 1
255 13417 5 Executor.exe 14 0 2

28. #.28
Copyright 2006 Kyle Hailey
Top Session w/ Username
select
decode(nvl(to_char(s.sid),-1),-1,'DISCONNECTED','CONNECTED')
"STATUS",
topsession.session_id "SESSION_ID",
u.name "NAME",
topsession.program "PROGRAM",
max(topsession.CPU) "CPU",
max(topsession.WAITING) "WAITING",
max(topsession.IO) "IO",
max(topsession.TOTAL) "TOTAL"
from ( {previous query} ) topsession,
v$session s,
user$ u
where
u.user# =topsession.user_id and
/* outer join to v$session because the session might be disconnected */
topsession.session_id = s.sid (+) and
topsession.session_serial# = s.serial# (+)
group by topsession.session_id, topsession.session_serial#, topsession.user_id,
topsession.program, s.username,s.sid,s.paddr,u.name
order by max(topsession.TOTAL) desc
select
decode(nvl(to_char(s.sid),-1),-1,'DISCONNECTED','CONNECTED')
"STATUS",
topsession.session_id "SESSION_ID",
u.name "NAME",
topsession.program "PROGRAM",
max(topsession.CPU) "CPU",
max(topsession.WAITING) "WAITING",
max(topsession.IO) "IO",
max(topsession.TOTAL) "TOTAL"
from ( {previous query} ) topsession,
v$session s,
user$ u
where
u.user# =topsession.user_id and
/* outer join to v$session because the session might be disconnected */
topsession.session_id = s.sid (+) and
topsession.session_serial# = s.serial# (+)
group by topsession.session_id, topsession.session_serial#, topsession.user_id,
topsession.program, s.username,s.sid,s.paddr,u.name
order by max(topsession.TOTAL) desc

29. #.29
Copyright 2006 Kyle Hailey
Top Session
Finding a Rogue User
STATUS SESSION_ID NAME PROGRAM CPU WAITING IO
--------------- ---------- ---------- ------------------------- ----- ---------- ----
CONNECTED 247 CPU_Monger ChMgr304.exe 11704 0 0
CONNECTED 277 SYS oracle@labsfrh903 (LGWR) 14 19 0
CONNECTED 278 SYS oracle@labsfrh903 (DBW0) 29 0 0
CONNECTED 276 SYS oracle@labsfrh903 (CKPT) 18 9 0
CONNECTED 280 SYS oracle@labsfrh903 (PMON) 20 0 0
DISCONNECTED 255 SYSTEM Executor.exe 11 4 5
DISCONNECTED 257 SYSTEM Executor.exe 13 0 3
DISCONNECTED 255 SYSTEM Executor.exe 14 0 2
DISCONNECTED 257 SYSTEM Executor.exe 13 0 3
STATUS SESSION_ID NAME PROGRAM CPU WAITING IO
--------------- ---------- ---------- ------------------------- ----- ---------- ----
CONNECTED 247 CPU_Monger ChMgr304.exe 11704 0 0
CONNECTED 277 SYS oracle@labsfrh903 (LGWR) 14 19 0
CONNECTED 278 SYS oracle@labsfrh903 (DBW0) 29 0 0
CONNECTED 276 SYS oracle@labsfrh903 (CKPT) 18 9 0
CONNECTED 280 SYS oracle@labsfrh903 (PMON) 20 0 0
DISCONNECTED 255 SYSTEM Executor.exe 11 4 5
DISCONNECTED 257 SYSTEM Executor.exe 13 0 3
DISCONNECTED 255 SYSTEM Executor.exe 14 0 2
DISCONNECTED 257 SYSTEM Executor.exe 13 0 3

30. #.30
Copyright 2006 Kyle Hailey
Act.sql : DB Detailed AAS
@act
Analysis Begin Time : 2007-07-24 11:04:48
Analysis End Time : 2007-07-24 11:19:45
Start time, mins ago: 15
Request Duration : 15
Collections : 528
Data Values : 3327
Elapsed Time: 15 mins
WAIT_EVENT CNT % Active Ave_Act_Sess
-------------------------------------- ---------- ------------
latch free 10 .3 .02
log buffer space 13 .39 .02
buffer busy waits 14 .42 .03
db file scattered read 15 .45 .03
library cache pin 78 2.34 .15
log file sync 213 6.4 .4
ON CPU 726 21.82 1.38
enqueue 855 25.7 1.62
db file sequential read 1399 42.05 2.65
------------
sum 6.3
@act
Analysis Begin Time : 2007-07-24 11:04:48
Analysis End Time : 2007-07-24 11:19:45
Start time, mins ago: 15
Request Duration : 15
Collections : 528
Data Values : 3327
Elapsed Time: 15 mins
WAIT_EVENT CNT % Active Ave_Act_Sess
-------------------------------------- ---------- ------------
latch free 10 .3 .02
log buffer space 13 .39 .02
buffer busy waits 14 .42 .03
db file scattered read 15 .45 .03
library cache pin 78 2.34 .15
log file sync 213 6.4 .4
ON CPU 726 21.82 1.38
enqueue 855 25.7 1.62
db file sequential read 1399 42.05 2.65
------------
sum 6.3

31. #.31
Copyright 2006 Kyle Hailey
Aveact.sql : AAS over time
@aveact
TM NPTS AVEACT GRAPH CPU WAITS
---------------- ------ ------- ---------------------- ---- -----
06-AUG 13:00:00 270 .33 +- 2 29 59
06-AUG 14:00:00 1040 2.24 ++--------2--- 341 1984
06-AUG 15:00:00 623 6.67 ++++------2---------- 438 3718
06-AUG 16:00:00 1088 2.59 ++--------2---- 335 2486
06-AUG 17:00:00 1104 1.26 ++----- 2 349 1043
06-AUG 18:00:00 1093 1.38 +++---- 2 663 842
06-AUG 19:00:00 1012 1.74 ++------- 2 373 1388
06-AUG 20:00:00 1131 .99 +---- 2 304 820
06-AUG 21:00:00 1111 1.22 ++----- 2 344 1012
06-AUG 22:00:00 1010 1.66 ++------ 2 414 1259
06-AUG 23:00:00 1120 1.08 +---- 2 298 913
07-AUG 00:00:00 1024 .83 +--- 2 273 576
07-AUG 01:00:00 1006 1.74 ++------- 2 319 1428
07-AUG 02:00:00 1090 2.47 ++--------2---- 347 2345
07-AUG 03:00:00 687 6.59 +++-------2---------- 382 4142
07-AUG 04:00:00 1004 1.95 ++++++--- 2 1299 659
07-AUG 05:00:00 1104 3.08 +++++-----2------ 1170 2226
07-AUG 06:00:00 1122 1.91 +++++++-- 2 1582 558
07-AUG 07:00:00 1115 1.06 +++--- 2 559 618
07-AUG 08:00:00 1140 .81 ++-- 2 403 519
07-AUG 09:00:00 1128 .88 ++--- 2 386 601
@aveact
TM NPTS AVEACT GRAPH CPU WAITS
---------------- ------ ------- ---------------------- ---- -----
06-AUG 13:00:00 270 .33 +- 2 29 59
06-AUG 14:00:00 1040 2.24 ++--------2--- 341 1984
06-AUG 15:00:00 623 6.67 ++++------2---------- 438 3718
06-AUG 16:00:00 1088 2.59 ++--------2---- 335 2486
06-AUG 17:00:00 1104 1.26 ++----- 2 349 1043
06-AUG 18:00:00 1093 1.38 +++---- 2 663 842
06-AUG 19:00:00 1012 1.74 ++------- 2 373 1388
06-AUG 20:00:00 1131 .99 +---- 2 304 820
06-AUG 21:00:00 1111 1.22 ++----- 2 344 1012
06-AUG 22:00:00 1010 1.66 ++------ 2 414 1259
06-AUG 23:00:00 1120 1.08 +---- 2 298 913
07-AUG 00:00:00 1024 .83 +--- 2 273 576
07-AUG 01:00:00 1006 1.74 ++------- 2 319 1428
07-AUG 02:00:00 1090 2.47 ++--------2---- 347 2345
07-AUG 03:00:00 687 6.59 +++-------2---------- 382 4142
07-AUG 04:00:00 1004 1.95 ++++++--- 2 1299 659
07-AUG 05:00:00 1104 3.08 +++++-----2------ 1170 2226
07-AUG 06:00:00 1122 1.91 +++++++-- 2 1582 558
07-AUG 07:00:00 1115 1.06 +++--- 2 559 618
07-AUG 08:00:00 1140 .81 ++-- 2 403 519
07-AUG 09:00:00 1128 .88 ++--- 2 386 601

32. #.32
Copyright 2006 Kyle Hailey
Aveact.sql

33. #.33
Copyright 2006 Kyle Hailey
“
“-” = WAIT
-” = WAIT
“
“+” = CPU
+” = CPU
which waits ? -> aveactn.sql
which waits ? -> aveactn.sql

34. #.34
Aveactn.sql
Copyright 2006 Kyle Hailey

35. #.35
Copyright 2006 Kyle Hailey
Many Ways to Attack Problems
Confusing
 How to Attack the problem?
 Top SQL?
 Top wait for that SQL?
 Top Waiting Session ?
 Top Waits for that Session
 Top Waits for Database?
 Top Session waiting for that wait
 Top SQL for that wait
Solution - Graphics

36. #.36
Copyright 2006 Kyle Hailey
Mining Data is Non Trivial
 Many Dimensions to consider
 Constantly Varying time frames
 Luckily 10g automates all of this functionality.
 collects all of the data
 analyses all the wait events
 reports on bottlenecks
 supplies solutions
 Graphics add tremendous ease and power

37. Session 1
Session 2
Session 3
Session 4
TIME
Graphical ASH

38. #.38
Copyright 2006 Kyle Hailey
Graph of User States

39. #.39
Copyright 2006 Kyle Hailey
One Second Graph

40. #.40
Copyright 2006 Kyle Hailey
15 Second Averages

41. #.41
Copyright 2006 Kyle Hailey
Maximum CPU Line

42. #.42
Copyright 2006 Kyle Hailey
Idle Users

43. #.43
Copyright 2006 Kyle Hailey
OEM Perf Page

44. #.44
Copyright 2006 Kyle Hailey
OEM Perf Page

45. #.45
Copyright 2006 Kyle Hailey
ASH
vs
Statistics
 Statistics
 are more expensive
 have lag time
 lack clear identification of culprits

46. #.46
Copyright 2006 Kyle Hailey
Statistic Lag Time
Counters
Counters
Samples
Samples
Slight Lags
Slight Lags

47. #.47
Copyright 2006 Kyle Hailey
CPU Lag Problem
 ASH is the only way to see CPU usage
realtime
 V$sysstat reports CPU but
 is only updated at the end of the call.
 Long calls look deceiving like no CPU is being
used

48. #.48
Copyright 2006 Kyle Hailey
CPU in ASH vs Stats

49. #.49
Copyright 2006 Kyle Hailey
ASH Sampling Cheap
Three Methods
1.With PL/SQL it’s less that 1 % CPU with 10
average active sessions
2.DMA - direct memory attach to SGA Using C
code 200x Cheaper
3.ASH in 10g should be even cheaper than
DMA because it’s done in the kernel

50. #.50
Copyright 2006 Kyle Hailey
ASH – In Memory
 Collects active session data only
 History v$session_wait + v$session + extras
 Circular Buffer - 1M to 128M (~2% of SGA)
 Flushed every hour to disk or when buffer 2/3
full (it protects itself so you can relax)

51. #.51
Copyright 2006 Kyle Hailey
ASH Sizing …
 Avg row around 150bytes
 3600 secs in an hour
 ~ ½ Meg per Active Session per hour
 That’s generally over an hour of ASH

52. #.52
Copyright 2006 Kyle Hailey
How ASH works
V$session_wait
+ v$session +
extras
MMON/
MMNL
v$active_session_history
wrh$_active_session_history
Only writes out 1 in 10 rows
via direct path inserts

53. #.53
Copyright 2006 Kyle Hailey
Select reads
backwards
-No latching
-No read consistency
-Index on time Insert point
ASH buffer
Insert one direction
- Touch up wait times

54. #.54
Copyright 2006 Kyle Hailey
Family of ASH Tables
v$session_wait
v$active_session_history
wrh$active_session_history
V$session_wait_history
DBA_HIST_ACTIVE_SESS_HISTORY

55. #.55
Copyright 2006 Kyle Hailey
ASH Tables
v$session_wait
SID
SEQ#
EVENT
P1TEXT
P1
P1RAW
P2TEXT
P2
P2RAW
P3TEXT
P3
P3RAW
WAIT_CLASS_ID
WAIT_CLASS#
WAIT_CLASS
WAIT_TIME
SECONDS_IN_WAIT
STATE
v$session_wait_history
SID
SEQ#
EVENT#
EVENT
P1TEXT
P1
P2TEXT
P2
P3TEXT
P3
WAIT_TIME
v$event_name
EVENT_ID
EVENT#
EVENT_ID
NAME
PARAMETER1
PARAMETER2
PARAMETER3
WAIT_CLASS_ID
WAIT_CLASS#
WAIT_CLASS
v$active_session_history
SAMPLE_ID
SAMPLE_TIME
SESSION_ID
SESSION_SERIAL#
USER_ID
SQL_ID
SQL_CHILD_NUMBER
SQL_PLAN_HASH_VALUE
SQL_OPCODE
SERVICE_HASH
SESSION_TYPE
SESSION_STATE
QC_SESSION_ID
QC_INSTANCE_ID
SEQ#
EVENT#
P1
P2
P3
WAIT_TIME
TIME_WAITED
CURRENT_OBJ#
CURRENT_FILE#
CURRENT_BLOCK#
PROGRAM
MODULE
ACTION
CLIENT_ID
current 10 samples hour
DBA_HIST_ACTIVE_SESS_HISTORY
wrh$active_session_history
SNAP_D
DBID
INSTANCE_NUMBER
SAMPLE_ID
SAMPLE_TIME
SESSION_ID
SESSION_SERIAL#
USER_ID
SQL_ID
SQL_CHILD_NUMBER
SQL_PLAN_HASH_VALUE
SQL_OPCODE
SERVICE_HASH
SESSION_TYPE
SESSION_STATE
QC_SESSION_ID
QC_INSTANCE_ID
SEQ#
EVENT_ID
P1
P2
P3
WAIT_TIME
TIME_WAITED
CURRENT_OBJ#
CURRENT_FILE#
CURRENT_BLOCK#
PROGRAM
MODULE
ACTION
CLIENT_ID
7 days (disk)
1 in 10

56. #.56
Copyright 2006 Kyle Hailey
Wait Time vs Time Waited
 SESSION_STATE
 Waiting, on CPU
 Based on WAIT_TIME
 WAIT_TIME (v$session, v$session_wait, v$ash)
 0 => waiting
 >0 => CPU (value is time of last wait)
 TIME_WAITED
 Actual time waited for event
 0 until wait finishes
 Fix up values (no one else can do this)

57. #.57
Copyright 2006 Kyle Hailey
Oradebug
 Dump to trace file
SQL> oradebug dump ash 5
SQL> Alter session set events ‘immediate
tracename ashdump level 5’;
level 5 = # of minutes
loader file rdbms/demo/ashldr.ctl
SQL> oradebug dump ashdump 5
SQL> Alter session set events ‘immediate
tracename ashdump level 5’;

58. #.58
Copyright 2006 Kyle Hailey
INIT.ORA
statistics_level = Typical (default)
PARAMETER SESSION_VALUE INSTANCE_VAL
----------------------- ---------- ------------
_ash_sampling_interval 1000 1000
milliseconds
_ash_size 1048618 1048618
ASH buffer size
_ash_enable TRUE TRUE
Turn on/off ASH sampling, flushing and the V$ views on ASH
_ash_disk_write_enable TRUE TRUE
Flush to disk
_ash_disk_filter_ratio 10 10
write 1 in 10 points
_ash_sample_all FALSE FALSE
Sample including idle waits

59. #.59
10.2 ASH Extras
 BLOCKING_SESSION
 BLOCKING_SESSION_STATUS
 BLOCKING_SESSION_SERIAL#
 P1TEXT
 P2TEXT
 P3TEXT
 WAIT_CLASS
 WAIT_CLASS_ID
 XID
 FORCE_MATCHING_SIGNATURE
59
01/30/15

60. #.60
Copyright 2006 Kyle Hailey
10.2 Extras
 10gR2 add fields to ASH
 Blocking Session Id, serial# and state ***
 XID, transaction ID
 RAC event Fixup
 Plan Hash Fix up
 10gR1 - during parsing no plan, good way to find parsing
problems
 10gR2 – get plan hash fixup – good but lose some ability to find
parsing problems
 Wait Class, needed this for grouping
 Force_matching_signature – sql profile id

61. #.61
10.2.0.3 ASH Extras
PLSQL_ENTRY_OBJECT_ID
PLSQL_ENTRY_SUBPROGRAM_ID
PLSQL_OBJECT_ID
PLSQL_SUBPROGRAM_ID
61
01/30/15
ALL_PROCEDURES
ALL_PROCEDURES
where object_id = plsql_object_id
where object_id = plsql_object_id
and subprogram_id = plsql_subprogram_id
and subprogram_id = plsql_subprogram_id

62. #.62
62
01/30/15
PLSQL Tracking
Package/Procedure/SQL tracking 10.2.0.3
calling_code SQL_ID COUNT(*)
----------------------------------------------- ----------
ORDERENTRY.NEWORDER 0uuqgjq7k12nf 258
ORDERENTRY.NEWCUSTOMER 0bzhqhhj9mpaa 262
ORDERENTRY.BROWSEANDUPDATEORDERS 41zu158rqf4kf 301
ORDERENTRY.NEWORDER 0yas01u2p9ch4 569
PARSE_SAME 3vjxpmhhzngu4 874
ORDERENTRY.BROWSEANDUPDATEORDERS 05s4vdwsf5802 1669
select
object_name package||.|| procedure_name, sql_id, count(*)
from v$active_session_history ash,
all_procedures procs
where
ash.PLSQL_ENTRY_OBJECT_ID = procs.object_id
and ash.PLSQL_ENTRY_SUBPROGRAM_ID = procs.SUBPROGRAM_ID

63. #.63
Copyright 2006 Kyle Hailey
11g ASH extras
SQL Elapsed
SQL Elapsed
SQL_EXEC_ID
SQL_EXEC_START
IN_CONNECTION_MGMT
IN_PARSE
IN_HARD_PARSE
IN_SQL_EXECUTION
IN_PLSQL_EXECUTION
IN_PLSQL_RPC
IN_PLSQL_COMPILATION
IN_JAVA_EXECUTION
IN_BIND
IN_CURSOR_CLOSE
SQL_PLAN_LINE_ID
SQL_PLAN_OPERATION
SQL_PLAN_OPTIONS
CURRENT_ROW#
EVENT#
QC_SESSION_SERIAL#
CONSUMER_GROUP_ID
FLAGS
ETC
ETC
CPU Analysis – non Timed
CPU Analysis – non Timed
SQL Row Source
SQL Row Source
REMOTE_INSTANCE#
RAC – remote transfers
RAC – remote transfers
TOP_LEVEL_SQL_ID
TOP_LEVEL_SQL_OPCODE
Recursive SQL
Recursive SQL

64. #.64
Copyright 2006 Kyle Hailey
11g ASH extras
Run-time SQL row source information
 Identifies current row source within plan
SQL execution ID
 Is this same execution as last sample?
 can see how long sql has been running
Operation bit vector
 Capture non-timed operations
 Examples: fetch, binding, close
Remote instance id for Cache transfers
 Which instance sourced requested block?

65. #.65
Copyright 2006 Kyle Hailey
How Many Active Sessions?
 How much data does ASH Collect ?
 1 CPU means max 1 Avg Active Session unless
there is a bottleneck
Big site examples:
 Oracle 4 way RAC internal apps
 10,000 connected, 200 active
 One Site
 3000 connected, 30 Active
 Site
 12,000 connected, 100 active

66. #.66
Copyright 2006 Kyle Hailey
Simulating ASH
 ASH is new in 10g
 ASH data exist since V7
 Need Diagnostic Pack License 
 Collect it yourself 
 SASH – Simulated ASH
http://perfvision.com/sash.php
 Graphical Monitor
http://perfvision.com/ashmon.php
Consumes < 1% CPU for 10 active sessions (a lot)

67. #.67
Copyright 2006 Kyle Hailey
Sampling
 Sampling is the future
 Took clean vision to create
 Bit of a leap of faith
 Less Accurate but more powerful than past
 Inaccuracies unimportant for the most part
 Feasible since version 7
 You can implement it yourself
 Graphics are the only way to full harness the
power

68. #.68
Copyright 2006 Kyle Hailey
Summary
 To solve hard problems you need Sampling
 If you have 10g and a license you can use
 V$active_session_history
 OEM 10g (can access some 9 sampling)
 ?/rdbms/admim/ashrpt.sql
 If you are on 7,8,9 or 10g without the license
 Need custom sampling
 SASH – Simulated ASH http://perfvision.com/ash.php
 ASHMON – graphical http://perfvision.com/ashmon.php

69. #.69
Copyright 2006 Kyle Hailey
ASH Summary
Faster, Cheaper, instant (no lag) …
but most importantly
Rich & Multidimensional
 Overview of system load
 Drilldowns into problems
 Sql
 Session
 Wait event
 Details information on problem resolution
 OEM simplifies mining of ASH data