UKOUG

AWR and ASH Deep Dive with
Enterprise Manager 12c and
Beyond
Kellyn Pot’Vin
Consulting Member of Enterprise Manager Technical Team
Strategic Customer Program
December, 2014
Copyright © 2014 Oracle and/or its affiliates. All rights reserved. |
Oracle Confidential

Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
Oracle Confidential 4

Program Agenda
1
2
3
4
5
ASH/AWR Reports in EM12c
Compare ADDM
SQL Monitor
ASH/AWR Reporting from the Command Line
Search SQL, (Least Used Feature of EM)
ASH Queries
AWR Warehouse
6
7

When Someone Does’t Use AWR and ASH

Brief History
• ASH= Active Session History
• AWR= Automatic Workload Repository
• Introduced in Oracle 10g
• Evolution to statspack, requests for performance reporting improvements.
• “Always on” approach to performance metrics with requirement of non-locking
collection process.
• Requires Tuning Management Pack License from Oracle.

Where We Will be Spending our Time Today…

Running ASH Report from EM
• ASH is by time, not snapshot.
• Set start date and time.
• End date and time
• Generate report

HTML Format ASH

Main ASH Info

Top SQL, Top Sessions

Top SQL Details

Top Parallel, Top DB Files

How Often Are We Asked, “What Changed?”
• It ran fine last week, now it doesn’t!
• ETL loads have changed, but no one has released any new code!
• The DBA says there hasn’t been any parameter changes to this database,
but I’m sure there have been.
• Compare ADDM Comparison Resolution

What is in an ADDM Compare?
• Report Includes Following:
– Clear Demonstration of impact of change.
– Recommendations to address issue.
– Identifies causes behind change, (with limitations.)
– Lists Regressed SQL, too!
– Tip: If Installing to database for first time, (simple installation, nothing to concern
about, just pkg to fulfill views) you must have preferred credentials SET of install will
fail!

Executing a Report from EM12c
• Choose focus period
• Choose to compare to an Offset, Baseline or Custom

A Comparison ADDM Report…
• Report Includes Following:
• Clear Demonstration of impact of change.
• Recommendations to address issue.
• Identifies causes behind change, (with limitations.)
• Lists Regressed SQL, too!
Tip: If Installing to database for first time, (simple installation, nothing to
concern about, just pkg to fulfill views) you must have preferred credentials
SET of install will fail!

Performing a Comparison
Yes, you can compare one
snapshot against another
snapshot in DIFFERENT
database if you are using this
in AWR Warehouse! 

2-3pm, Compared on the 12th vs. the 13th
• Familiar interface with visual wait event comparisons.
• Average # of sessions during each period are displayed.

Detailed Report
High level data, highlight for analysis and recommendations

Regression SQL
Any performance degradation is noted with the down arrow icon:

Top Segments Causing IO Waits
• High Level data
• Click on “Show Hot Object Breakdown” to see more detail.

Resource Comparisons
• Comparisons of Memory, CPU, IO and Interconnect.
• Memory Is there Virtual paging?
- Memory Base Period
- Memory Comparison Period

Dashboard Provided for CPU, Memory, IO and Interconnect
• Is something OTHER than Oracle the cause?

IO Bound Dashboard
• Base vs. comparison period
• Temp reads/writes specified
• Single block read latency

SQL Monitor in EM12c
Status of Statement
Wait Events
Degree of
Parallelism
SQL_ID
SQL Text

Exadata and Offloading
• Drill down to specific statement within SQL Monitor will display offload
efficiency per statement.

Full Detail of SQL Execution

View Report

SQL Monitor Report CLI
SET LONG 1000000
SET LONGCHUNKSIZE 1000000
SET LINESIZE 1000
SET PAGESIZE 0
SET TRIM ON
SET TRIMSPOOL ON
SET ECHO OFF
SET FEEDBACK OFF
SELECT DBMS_SQLTUNE.report_sql_monitor(
sql_id => '5vh6y3b7tnv8r',
type => 'TEXT',
report_level => 'ALL') AS report
FROM dual;

Text Output of SQL Monitor

One of the Best & Least Used Features in EM(10g, 11g, 12c)
Search SQL
Problem Query

We Have the SQL_ID, What Next?
4v2tsp8dz0nhn is our SQL_ID
Go to the EM Console, (Example is EM12c)

Search SQL Interface
• Choose AWR Snapshots, (change Time Period), AWR Baselines and put
SQL_ID

Click on Search
• SQL_ID link for SQL Details
• Split up by tabs for Cursor, AWR, Baselines and SQL Tuning Sets
• Plan Hash Value
• Elapsed Time

AWR Data

Snapshot IDs
• Click on Snapshot ID and gather valuable data on resource usage during
snapshot time or choose to view report.

AWR Report or Run ADDM Report

AWR and ASH from the CLI
All DBAs should know how to do this,
(plus, Thor commands it!)

Running Reports, Command Line
$ORACLE_HOME/rdbms/admin/awrrpt.sql;
$ORACLE_HOME/rdbms/admin/ashrpt.sql;
$ORACLE_HOME/rdbms/admin/awrsqlrpt.sql;
Less Known AWR Reports:
awrinfo.sql General AWR Info
awrddrpt.sql Comparison report between snapshots
awrblmig.sql Migrates pre-11g baseline data into 11g Baseline tables.
awrgrpt.sql RAC Aware AWR Report.

AWR Info Report
• Snapshot Interval Information
• Basic Info on Instances and Nodes
• No User or Application Schema info.
• Space Usage by SYSAUX
• WRH$ and Non- AWR Objects, ordered by size
• Snapshot info and if any errors.
• Advisor Tasks
• Use for sizing AWR Warehouse estimates.

AWR Info Report

ASH Report
@$ORACLE_HOME/rdbms/admin/awrrpt.sql;
-Report Format: Text or HTML
-Days to view snapshot IDs
-Beginning and Ending Snapshot ID’s
- Name of Report

ASH Report
@$ORACLE_HOME/rdbms/admin/ashrpt.sql;
-Report Format: Text or HTML.
-Timestamp to being report from.
-Duration in minutes.
-Name of report.

SQL_ID Specific AWR Report

“Interesting Part”

Finale!
Select * from table(dbms_xplan.display_awr(‘43mp3mjufgnkg’));

Querying ASH Data Directly
• More defined reporting
• No need to pull full report
• Detail on waits that are of interest
• Join to non-AWR objects
• Examples and Ideas…

V$ACTIVE_SESSION_HISTORY
• SAMPLE_ID- This is a unique identifier within an ASH sample.
• SAMPLE_TIME- A unit of time used by Active Session History, (not to be confused with DB_TIME)
• USER_ID- Identifier for a user that’s executing the session.
• SESSION_ID- Same as the SID or Session ID and can be used to join to SID in other views/tables.
• SESSION_STATE- What was the state of the session when ASH recorded the sample.
• ON CPU/WAITING- The two session states in Active Session History. ON CPU is Active, vs. Waiting, which
is self-explanatory.
• EVENT- Type of event that the session is currently active or waiting on.
• TIME_WAITED- How long the session has been waiting if waiting.
• WAIT_TIME- Confusing- but this is populated by any wait time if the session is currently active and for
the previous waits.
• SQL_ID- The unique identifier for the SQL statement being executed.
• SQL_CHILD_NUMBER-The cursor child number.

Session Averages
select
ROUND(RATIO_TO_REPORT(SUM(1)) OVER () * 100 ,2) PERCENTAGE, ash.session_type
SESS_TYPE,
session_state STATUS, decode(nvl(sql_id,'-1'),'-1','nonsql','sql') SQL_TYPE,
count(distinct to_char(session_id)|| to_char(session_serial#)) SESS_CNT from
v$active_session_history ash
where
sample_time > sysdate - 30/(24*60) and (( ash.session_state = 'ON CPU' )
or ( ash.session_type != 'BACKGROUND' ))
group by
ash.session_type,
ash.session_state, decode(nvl(sql_id,'-1'),'-1','nonsql','sql')
order by count(*)
/

Session Avg. Output
• Note the % of Background processes

Inspecting What
select * from (select
ash.SQL_ID , ash.SQL_PLAN_HASH_VALUE Plan_hash, aud.name type,
sum(decode(ash.session_state,'ON CPU',1,0)) "CPU",
sum(decode(ash.session_state,'WAITING',1,0)) "WAITING",
sum(decode(ash.session_state,'WAITING', decode(wait_class, 'User I/O',1,0),0))
"IO WAIT" ,
sum(decode(ash.session_state,'WAITING', decode(wait_class,'User I/O',1,0),0))
"IO" ,
sum(decode(ash.session_state,'WAITING', decode(wait_class, 'Concurrency',1,0)))
"CONCURRENCY" ,
sum(decode(ash.session_state,'WAITING', decode(wait_class, 'Application',1,0)))
"Application" , sum(decode(ash.session_state,'ON CPU',1,1)) "TOTAL“
from v$active_session_history ash, audit_actions aud
where SQL_ID is not NULL
and ash.sql_opcode=aud.action and ash.sample_time > sysdate - &minutes /( 60*24)
group by sql_id, SQL_PLAN_HASH_VALUE , aud.name
order by sum(decode(session_state,'ON CPU',1,1)) desc) where rownum < 5;

10 Min. View of Waits by SQL_ID
• Choose Time in Minutes To Review, (10 in our example)
• SQL_ID and Plan Hash Value Shown
• Waits for CPU, Wait, IO Wait and others.

Quantity of Events Occurred Over Small Amounts of Time
Col event for a50
select event, count(1)
from v$active_session_history
where sample_time between
to_date('21-FEB-14 01.43.00 PM','dd-MON-yy hh:mi:ss
PM')
and
to_date('21-FEB-15 01.53.00 PM','dd-MON-yy hh:mi:ss
PM')
group by event
order by event;

Results, Where to Focus?

Transaction Wait Detail
select
to_char(sample_time,'HH:MI') st, substr(event,0,20) event,
ash.session_id sid, mod(ash.p1,16) lm, ash.p2,ash.p3,
nvl(o.object_name,ash.current_obj#) objn,
substr(o.object_type,0,10) otype, CURRENT_FILE# fn,
CURRENT_BLOCK# blockn, ash.SQL_ID,
BLOCKING_SESSION bsid
from v$active_session_history ash, all_objects o
where event like 'enq: TX%'
and o.object_id (+)= ash.CURRENT_OBJ#
and sample_time > sysdate - 10/(60*24)
order by sample_time;

Transaction Lock Output
• What TX row locks are occurring!

Knowing What’s in the ASH Buffer
• Deters from making assumptions on what data is being queried.
• Know your samples!

Wait Events Across Nodes

Query top
10 SQL_ID’s
in the last
10 minutes?

SQL_ID and CPU Usage

IO Waits by Object from ASH

SQL Text with ASH
• SQL for most recent five minutes of sample data from ASH

SQL Results
• SQL_ID, SQL Text, Sample Time that Process was captured in.

Average Activity- Graphed

SELECT
to_char(to_date(tday||' '||tmod*&v_secs,'YYMMDD SSSSS'),'DD-MON HH24:MI:SS') tm, samples npts,total/&samples aas,
substr(substr(substr(rpad('+',round((cpu*&v_bars)/&samples),'+') || rpad('-',round((waits*&v_bars)/&samples),'-') ||
rpad(' ',p.value * &v_bars,' '),0,(p.value * &v_bars)) || p.value || substr(rpad('+',round((cpu*&v_bars)/&samples),'+')
|| rpad('-',round((waits*&v_bars)/&samples),'-') || rpad(' ',p.value * &v_bars,' '),(p.value * &v_bars),10) ,0,30)
,0,&v_graph)graph,total,cpu, waits
FROM (
SELECT to_char(sample_time,'YYMMDD')tday, trunc(to_char(sample_time,'SSSSS')/&v_secs) tmod,
sum(decode(session_state,'ON CPU',1,decode(session_type,'BACKGROUND',0,1))) total, (max(sample_id) - min(sample_id) + 1 )
samples, sum(decode(session_state,'ON CPU' ,1,0) cpu,
sum(decode(session_type,'BACKGROUND',0,decode(session_state,'WAITING',1,0))) waits
FROM v$active_session_history
WHERE sample_time > sysdate - &v_hours/24
GROUP BY trunc(to_char(sample_time,'SSSSS')/&v_secs), to_char(sample_time,'YYMMDD')
UNION ALL
SELECT
to_char(sample_time,'YYMMDD')tday, trunc(to_char(sample_time,'SSSSS')/&v_secs) tmod, sum(decode(session_state,'ON
CPU',10,decode(session_type,'BACKGROUND',0,10))) total, (max(sample_id) - min(sample_id) + 1 ) samples,
sum(decode(session_state,'ON CPU' ,10,0))cpu,
sum(decode(session_type,'BACKGROUND',0,decode(session_state,'WAITING',10,0))) waits
FROM dba_hist_active_sess_history WHERE sample_time > sysdate - &v_hours/24 AND sample_time < (select min(sample_time)
FROM v$active_session_history)
GROUP BY trunc(to_char(sample_time,'SSSSS')/&v_secs), to_char(sample_time,'YYMMDD')) ash, v$parameter p
WHERE p.name='cpu_count‘ ORDER BY to_date(tday||' '||tmod*&v_secs,'YYMMDD SSSSS');

Pivot the Wait Events

Digging into History
• DBA_HIST_ACTIVE_SESS_HISTORY
– SNAP_ID
– SAMPLE_ID
– SAMPLE_TIME
– SESSION_ID
– USER_ID
– SQL_ID
–WAIT_CLASS
– SESSION_STATE
– PGA_ALLOCATED

Process Information
SELECT * FROM (
SELECT /*+ PARALLEL(4) */
count(*) AS count,
user_id, program, module, sql_id
FROM SYS.DBA_HIST_ACTIVE_SESS_HISTORY
WHERE sample_time > TO_DATE('19-FEB-2014 03.00.00 PM','dd-MON-yy hh:mi:ss PM')
AND sample_time < TO_DATE('19-FEB-2014 08.00.00 PM','dd-MON-yy hh:mi:ss PM')
AND program LIKE 'oracle@%'
GROUP BY user_id, program, module, machine, sql_id
ORDER BY count(*) desc
)
WHERE rownum <= 20
/

Results of Process History

Tyler Muth ASH Mining Query

ASH Mining Output
Additional Options:
• Physical Read Averages
• Physical Writes, (Max/Averages)
• Redo Info
• Login Info
• Hard Parsing, etc.

Best Practice When Querying ASH Data
• Keep it Simple and don’t reinvent the wheel.
• Samples are an alias for time, not for counts.
• Understand what is valuable and compare to packaged reports.
• Be aware on RAC of node specific data.
• Take care when querying Obj#, File# and Block#, (still issues in different
versions…)
• Check the time that is available in buffer, don’t assume!

AWR/ASH Links/Blogs
• Tyler Muth: http://tylermuth.wordpress.com/
• Kyle Hailey, John Beresniewicz, Graham Wood: http://ashmasters.com/
• Mine- “For the Love of ASH and AWR” http://dbakevlar.com/2011/02/for-the-
love-of-awr-and-ash/
• Karl Arao- http://karlarao.tiddlyspot.com/
• Guy Harrison- http://guyharrison.squarespace.com/opsgsamples/

Why an AWR Warehouse?
1. Centralized location offers space savings to retain AWR data in local
SYSAUX tablespace.
2. Ability to offload resource demands when doing deep analysis and
historical trending of AWR data on source database.
3. Centralizing the data, identified by Database identifier, host, allows
analysis on more than one database without database links.

AWR Warehouse in EM12c
• Automatic Workload Repository
(AWR) is the de facto
performance repository for
Oracle databases since 10g
• Default retention period of 8
days prevents diagnosis of long
term performance problems
(“Compare performance during
this quarter’s books close with
last quarter’s”)
• Increasing AWR retention
period increases overhead and
cost in critical production
environments
Finance CRM Supply Chain
120%
90%
60%
30%
0%
120%
90%
60%
30%
0%
120%
90%
60%
30%
0%

Requirements
• AWR Warehouse Repository -11.2.0.4 or higher.
• Preferred Credentials set up for all targets involved.
• Discover the database you will use for your repository in the EM12c
• Pre-discover any source database before able to add.
• For a RAC target or AWR Warehouse, ensure you’ve set up a shared
location for the ETL load files.

AWR Warehouse - Architecture
• Central warehouse configured for
long term AWR data retention
• Historical and ongoing AWR
snapshots collected from databases
enabled for AWR warehouse
• ETL jobs moves snapshots from
source databases into AWR
warehouse
• Retention period configurable for
weeks, months, years or forever
(default)

Requirements
• AWR Warehouse Repository database must be 11.2.0.4 with patch or
12.1.0.2 with patch.
• Will support source databases 10.2.0.4  12.1.0.x
• EM12c 12.1.0.4 with
• Requires diagnostic and tuning pack. With these, limited EE license for use
of AWR Warehouse Repository database.
• As long as no additional, (RAC, Dataguard, etc.) on AWR Warehouse
repository database, the limited EE license will support.

All data identified by OLD/NEW DBID and
with the EM_ID, (CAW_DBID_MAPPING in
AWR WAREHOUSE)
AWR ETL Jobs
Oracle Confidential – Internal/Restricted/Highly Restricted 82
DBMS Job on Source Database
to directory
Job in EM Job Service that
pulls file from Source
Target and then pushes to
AWR Warehouse Target
Directory Final DBMS Job Inserts data
into AWR Warehouse
Source Target
Enterprise Manager
AWR Warehouse

Source Database ETL Job
DBMS Scheduler Job Name: MGMT_CAW_EXTRACT
Exec Call: begin dbsnmp.mgmt_caw_extract.run_extract; end;
How Often: 3 Hour Intervals if “playing catch up”, otherwise, 24 hr interval.

EM12c EM Job
• Agent to agent push.
• No other interaction with
EM12c outside of interface.

AWR Warehouse ETL Load Job
DBMS Scheduler Job Name: MGMT_CAW_LOAD
Exec Call: begin dbsnmp.mgmt_caw_load.run_master;
How Often: 5 Minute Intervals
Biggest Resource Demand from the “run_master”:
begin dbms_swrf_internal.move_to_awr(schname => :1); end;

New DBSNMP Objects
CAW_EXTRACT_PROPERTIES : Information on ETL job, dump location and
intervals.
CAW_EXTRACT_METADATA : All data about extracts- times, failures, details.

Accessing
• First access, will be asked to set up AWR Warehouse to database.
• Request to add first source database to repository.

AWR Warehouse Interface
• Warehouse dashboard tracking
ETL jobs
• All AWR features available on long
term AWR data
• Performance page
• AWR report
• ASH analytics
• Compare Period ADDM
• Compare Period Report
• Integrated seamlessly into EM UI
• Zero runtime overhead on source
Production databases

How Do You Know You are Using it?
• Upper right hand corner drop down
• Can switch between and if non-existent, console will inform the user.

AWR Warehouse Configurations
Along with AWR Warehouse Basics-
• Configuration Status
• Version of Repository Database
• Host Information
• Connect Info, (SID/Service Name, Port)
• Space Usage, Upload Interval and Retention

Databases and Reports
Considerable report options
Add or remove source databases to the warehouse.

Snapshots
View snapshot loads per day
High loads due to catch up, new source db’s.

Database Details
• Database, go to DB Details Page
• DB Type, DB Name, Version, Owner, Enabled
• Snapshot Information

Upload Information
• Add
• Highlight, Remove
• Highlight, View Errors
• Privileges to Manage
Snapshots

Snapshot Information
• Oldest
timestamp
• Newest
timestamp
• Days of
Snapshots
• Count

Database List
Clicking on Target Name will TAKE YOU TO DB Performance
Home Page!

Menu

ETL Load Errors

Managing Snapshot Privileges
• Viewing Access
• Manage Snapshots
• Retention Time
• Removal of Snapshots

Centralized AWR Warehouse Objects
Simple and clean schema edition to the DBNSMP.

What Can I do with the AWR Warehouse?
Oracle Confidential – Internal/Restricted/Highly Restricted 101
400000
350000
300000
250000
200000
150000
100000
50000
0
June 10, 2013
l_reads_s read_iops_max read_iops_direct read_iops_direct_max
600000
500000
400000
300000
200000
100000
0
June 10, 2014
l_reads_s read_iops_max read_iops_direct read_iops_direct_max

CPU Usage Issues
“Nothing’s changed in
months…”

Using the AWR Warehouse for Capacity Planning
“Do we really need more
partitioning and pruning?
Our disk usage hasn’t
increased this last year….”

CAW_DBID_MAPPING Table
Most important table for anyone querying the AWR
Warehouse!

Querying the AWR Warehouse Tips
Update Scripts with DBID identified to filter.
Join:
• CAW_DBID_MAPPING on OLD_DBID/NEW_DBID=DBID
• CAW_DBID_MAPPING on TARGET_NAME=TARGET_NAME

How Current AWR Queries Change
from dba_hist_sys_time_model stm, dba_hist_snapshot s, gv$parameter p, dbsnmp.caw_dbid_mapping m
where stm.stat_name in ('DB CPU','background cpu time')
and LOWER(m.target_name)= '&dbname'
and s.dbid= m.new_dbid and s.snap_id = stm.snap_id
and s.dbid = stm.dbid and s.instance_number = stm.instance_number
and p.name = 'cpu_count' and p.inst_id = s.instance_number)

Answer Specific IT Questions

Updating Existing AWR Queries to Go Across Hosts
select * from (
select
m.target_name,
sum(CPU_TIME_DELTA),
sum(DISK_READS_DELTA),
count(*)
from
DBA_HIST_SQLSTAT a, dba_hist_snapshot s, dba_hist_database_instance di, dbsnmp.caw_dbid_mapping m
where di.host_name='&host'
and di.dbid in m.new_dbid
and m.new_dbid = a.dbid
and a.snap_id = s.snap_id
and s.begin_interval_time > sysdate -120
group by m.target_name
order by
sum(CPU_TIME_DELTA) desc)

Graphing CPU Usage Per DB for One Host

AWR Warehouse Scripts at DBAKevlar.com
More scripts added as time
goes by…

Want to Learn More?
Oracle Screenwatch: https://www.youtube.com/watch?v=StydMitHtuI
DBAKevlar Blog Posts:
http://dbakevlar.com/2014/06/awr-warehouse-in-em12c-rel-4/
http://dbakevlar.com/2014/06/awr-warehouse-in-em12c-rel-4-part-ii/
Scripts: http://dbakevlar.com/scripts/

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