AWR, ASH with EM13 at HotSos 2016

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Performance Data with EM13c and
DB12c
AWR , ASH and Other Performance Data Deep Dive
Kellyn Pot’Vin-Gorman
Consulting Member of Technical Staff, SCP
Enterprise Manager
March, 2016

DBA Kevlar, the Geek Goth Girl

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.

Why an Updated Session
While building and testing the Performance Tuning DB12c exam, it became
apparent is was needed.

Program Agenda
Revisit to AWR
Top Changes
Automatic Workload Repository
Active Session History
The Rest of the Cool Stuff
1
2
3
4
5

Program Agenda with Highlight
Revisit to AWR
Top Changes
The Rest of the Cool Stuff
1
2
3
4
5

History of AWR and ASH
• 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 Management Diagnostic Pack License from Oracle.

AWR and ASH Architecture
DBA_HIST Views
V$ Views
Along with AWR Data
Memory Buffers write one way, users read the
opposite direction!
and MMON

Why Do We Combine Diagnostic and Tuning Packs?
Tuning Pack includes the Following:
• SQL Monitor
• SQL Access Advisor
• SQL Tuning Advisor
These products source their data from AWR….

Other Important Reports to know:
$ORACLE_HOME/rdbms/admin/awrrpt.sql;
$ORACLE_HOME/rdbms/admin/ashrpt.sql;
$ORACLE_HOME/rdbms/admin/awrsqlrpt.sql;
awrinfo.sql General AWR Info –Very important for AWR Warehouse!
awrddrpt.sql Comparison report between snapshots
awrgrpt.sql RAC Aware AWR Report.

What NOT to DO to the AWR
• Underscore parameter changes to spfile that change the default settings
for ASH samples, intervals, etc.
– DON’T DO IT. Step away….walk away from the keyboard. NOW.

Program Agenda with Highlight
Revisit to AWR
Top Changes
Rest of the Cool Stuff
1
2
3
4
5

A lot of additions for In-Memory!
• Manageability support for In-Memory Column Store
• The new Oracle Database In-Memory Column Store (IM column store)
feature accelerates database performance of analytics, data warehousing,
and online transaction processing (OLTP) applications.
• SQL Monitor report, ASH report, and AWR report now show statistics for
various in-memory operations.

Configuring is Now a Breeze

Managing Even Easier with In-Memory Central

New to ASH Analytics
Average Active Sessions chart
• Click on CPU wait class to see its breakdown by CPU usage for various in-
memory operations
• View various CPU used for operations other than in-memory operations.

Why Are These Changes Important?
In-memory Column store data is very quick to query, but just like other
features, if advanced sorting and “massaging” of the data is required,
complex performance issues can arise.
AWR and Enterprise Manager offers a window into these when challenges
occur.

Report Changes
Top ADDM Findings as Part of the AWR Report

Foreground Events
Displays Top TEN Foreground Events
CPU Should be
top…to a point…

Top Elapsed Time is Still King
Tune for time or you’re wasting time…

Changes in AWR Report for In-Memory
In-Memory Segments Statistics
• Shows in-memory segment consumption based on various attributes,
such as, scans, DB block changes, populate CUs, and repopulate CUs.
• Time Model Statistics section shows statistics related to in-memory CPU
usage and Instance Activity Statistics section shows statistics related to
in-memory activities.

Wait Class by Total Wait Time

The IO Profile
For OLAP and DSS Systems, Great Section in Report

Other New Sections
• Goldengate
• Xstreams
• Resource Stats
• Advanced Queuing Data

Example of Why AWR is Still the Gold Standard
• EM Health Review in Preparation to Upgrade to EM13c
• EM Diagnostics is Run on Repository, OMS and Agents.
• Author of Diagnostics starts from OMS tier, unsure of what is impact
Where do I start in the Diagnostics data as an Optimization DB Specialist?

AWR Data in Part of EM Diagnostics, (OMSVFY)
There are no
mviews in the
OMR!
Never heard of you!

Physical Reads
You both are an
unknown!

The Folly
Created Materialized View
on top of Metric Tables
Used by Enterprise Mgr
Mview created pressure
on roll up processing that
aggregate the data from
source tables.
To eliminate the
overhead, the rollup
jobs were shut off
Mview AND EM console
slow to unusable state as
raw metric tables become
huge.
Creates
own
schema
objects
Loads
more
into own
objects

Time Requirements
Without Using AWR Data for Healthcheck to Diagnose Performance Issues
With Using AWR Data for Healthcheck to Diagnose Performance Issues
8 Months and No Answer
12 Hours and Resolution

The Best of ASH
1. Active Session History work off ASH Time with ASH samples and not
exclusive to AWR snapshots.
2. Small Windows of time to isolate database challenges.
3. Shows the “Forrest for the Trees”. Great for Complex Issues.
4. Includes Blocking, DOP, Procedural calls and session information.

ASH Report Changes
• ASH report header table shows the size of in-memory pool under In
Memory Area column.
• Top Events, Top SQL, and Activity Over Time sections show CPU
consumption by various in-memory operations.

P Value Top Events
Table Presented

Saves You From Having to do This:
The values represent:
P1—The absolute file number for the data file involved in the wait.
P2—The block number within the data file referenced in P1 that is being
waited upon.
P3—The reason code describing why the wait is occurring.
select
p1 "File #“, p2 "Block #", p3 "Reason Code“ from
v$session_wait
where event = 'xxx';

Know the Module, Know the Action
Shows Percentage of Activity for Action

Top SQL and PL/SQL Procedures

Blocking Sessions Displayed Clearly

How Did it Change Over The Time Elapse?

ASH Analtyics, the New Top Activity

Details of SQL and Sessions…Plus More
Capability to update each column to demonstrate different data.

The Chameleon
View Data by Wait Class and Blocking Sessions

Using ASH Analtyics with Search SQL

Searching SQL with ASH Analytics
• Copy SQL_ID from ASH
Analtyics
• Go to Search SQL

Change Defaults
Include AWR, (ALL) and AWR
Baselines. Paste in the
SQL_ID before clicking on
“RUN”

Remember the Tabs
Click on SQL_ID to
proceed to Details

Why ASH shouldn’t be used for Auditing
Thanks to
Graham, Uri and
JB for this
wonderful
graphic!

Why Time is Important
Database Time
• Total time spent by sessions in the database server actively working,
(CPU) or actively waiting, (aka non-idle.)
Active Sessions
• The number of active sessions, (including waiting) in the database server
at a specific time is the rate of change of database time during that
period, (aka workload.)

Understanding ASH Time
DBTime is calculated as an approximate made up by multiplying sampling
interval by the total count of the samples.
Keeping in mind that each sample represents 1 second of DBTime…..
Then ASH Math results in:
COUNT(*) = <DBTime>
GROUP BY <Wait Event>

ASH Mining
Querying ASH, (V$ or
GV$ACTIVE_SESSION_HISTORY)
Data DIRECTLY to Answer a
Question….
• What are the top ten SQL ID’s
in the last ten minutes?

How Often Were SQL ID’s on CPU vs. Waiting on CPU?

Monitoring Database Activity, New School
SQL Monitor:
Is it done yet? Did it use parallel? What important data do we know?

Change My View, Change My Outlook
By updating the “Top 100 by” options, the data returned changes-

Details Top Info
• If it’s Exadata, It will show offload percentage.
• If it’s In-memory, it will include In-memory information.

What Kind of Resources in Layman Terms?
Very little and I can prove it….

SQL Monitor and Adaptive Plans
The Execution plan shows
The Plan Statistics tab contains a drop down list to show current plan, final
plan, and full plan. It also contains Plan Note button, which when clicked,
shows the notes that are generated in the explain plan for the SQL
statement.

Monitoring
Use SQL Monitor.
Execute on DBMS_SQL_MONITOR.REPORT_SQL_MONITOR
View on V$SQL_MONITOR and V$SQL_PLAN_MONITOR

Adaptive Plans in SQL Monitor

ASH Report Running Slow
ASH Report taking over 8 hrs to complete!
Sticking while pulling plan information on top SQL.
Pulled Execution plan- joins to X$ tables to
GV$Active_Session__History
Merge Join Cartesians and million row hash table that wasn’t possible
for amount of data in ash buffer.
Collected fixed stats, (X$ tables) to correct.

Enterprise Manager Slowness
Shut off SQL Baselines, (EM is NEVER GOING TO USE THEM!!
SQL> ALTER SYSTEM SET optimizer_capture_sql_plan_baselines=false SCOPE=both;
SQL> ALTER SYSTEM SET optimizer_use_sql_plan_baselines=false SCOPE=both;
Tune the Job Pool, 1st get recommendation
$ repvfy verify jobs -test 6007 -details
Then update to recommended value:
$ emctl set property -name oracle.sysman.core.conn.maxConnForJobWorkers
-value <recommended> -module emoms

Tips to Tuning the Enterprise Manager-
Java Heap is used heavily with the JVMD built into EM13c.
Update from the default to 8Gb is highly recommended:
$ emctl set property -name JAVA_EM_MEM_ARGS
-value "-Xms256m –Xmx8192m -XX:MaxPermSize=768M -
XX:+UseConcMarkSweepGC
-XX:+UseParNewGC -XX:+CMSClassUnloadingEnabled
-XX:CompileThreshold=8000 -XX:PermSize=128m"

The AWR Warehouse
• 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)

AWR ETL Jobs
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
All data identified by OLD/NEW DBID and
with the EM_ID, (CAW_DBID_MAPPING in
AWR WAREHOUSE)
Source Target
Enterprise Manager
AWR Warehouse

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

New More Efficient Job Interface

ADDM Comparison in AWR Warehouse
Yes, you can compare one
snapshot against another
snapshot in DIFFERENT
database! 

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

How Current AWR Mining 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)

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

Answer Specific IT Questions

Questions?

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AWR, ASH with EM13 at HotSos 2016

AWR, ASH with EM13 at HotSos 2016

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