awr, ash with em13 at hotsos 2016

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Performance Data with EM13c and DB12cAWR , ASH and Other Performance Data Deep Dive

Kellyn Pot’Vin-GormanConsulting Member of Technical Staff, SCPEnterprise ManagerMarch, 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

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Program Agenda with Highlight

Revisit to AWR

Top Changes




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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.



Revisit to AWR

Top Changes



Rest of the Cool Stuff

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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.



Revisit to AWR

Top Changes




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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



Revisit to AWR

Top Changes




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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



Revisit to AWR

Top Changes




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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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