DBA’s New Best Friend: Oracle Database 10g and 11g SQL
Performance Analyzer
Kurt Engeleiter
Product Manager
Database Manageability
Outline
• SQL Performance Analyzer (SPA) – Introduction
• Recommended Testing Methodology
• Usage Scenarios
– Evaluating Changes on Production System
– 10.2  11g DB Upgrade
• SPA Enhancements in Oracle Database 11g Release 2
• SPA Exadata Simulation
• Conclusion
SPA Motivation
• Businesses need to adapt to changes to stay competitive, compliant
and evolve
– DB upgrades, schema, optimizer statistics refresh
– SQL performance regressions: #1 cause of poor system perf.
• Current testing landscape and limitations
– Expensive capture, partial workload, non-production optimizer context,
binds
– Large workloads (100Ks SQL stmts are common)
– Manual and time consuming testing and regression tuning
– No end-to-end testing solution
– Test In Production is not too uncommon
SQL Performance Analyzer (SPA)
 Proactively detects ALL SQL regressions, BEFORE actual change is deployed
 Integrated comprehensive solution for end-to-end SQL workload testing
SPA Overview
•
•
Helps users predict the impact of
system changes on SQL workload
response time
Low overhead capture of SQL
workload to SQL Tuning Set (STS)
on production system
SQL Workload
STS
SQL plans + stats
Pre-change Trial
•
Build different SQL trials
(experiments) of SQL statements
performance by test execution
•
Analyzes performance differences
•
Offers fine-grained performance
analysis on individual SQL
•
Integrated with STS, SQL Plan
Baselines, & SQL Tuning Advisor to
form an end-to-end solution
Compare
SQL Performance
Analysis Report
SQL plans + stats
Post-change Trial
SQL Trials
• SQL Trials capture execution performance (plans and statistics) of the
STS under a given environment
• SPA Trials handle the SELECTS and query part of DML, DDL is skipped
• There are 3 methods to build SQL Trials:
– Execute SQL Locally or Remotely
• Test execute statements in actual environment
• For remote execution, database link needs to be specified
– Generate Plans Locally or Remotely
• Generated execution plans have bind visibility, so better than vanilla
“explain”
• Quick way to check if wide-spread changes to SQL plans
– Build from STS
• Convert STS to SQL Trial
• Use for SQL centric analysis with DB Replay or other testing tools
• Use for 9i/10.1 upgrade to higher releases
SPA: Common Usage Scenarios
• Database upgrades and patch-set releases
– 9.2/10.1 10.2 or 11g releases
– 10.2.0.x 10.2.0.y or 11g releases
• Optimizer statistics refresh
• Database parameter changes
• Database schema changes (e.g., add/drop indexes)
• Implementation of tuning recommendations
• I/O subsystem changes (e.g., ASM, Exadata)
SPA can be used for:
 any change that affects SQL execution plan & performance
 in production as well as test environments
Information for use cases on OTN/ML Note: 560977.1
SPA: Enterprise Manager Interface
• Rich GUI through Enterprise Manager – New workflows added!
• DBMS_SQLPA package PL/SQL API
New
Workflows
!
Recommended Testing Methodology
Real Application Testing: Recommended Methodology
1. USE SPA FOR SQL RESPONSE TIME /
UNIT TESTING
DONE?
No
Yes
2. USE DB REPLAY FOR LOAD /
CONCURRENCY TESTING
DONE?
No
Yes
DEPLOY CHANGE &
TUNING
Recommended Testing Methodology with SPA
1. CAPTURE REPRESENTATIVE SQL
WORKLOAD TO STS
2. ESTABLISH BASELINE (SQL TRIAL-1)
WITHOUT CHANGE
3. MAKE CHANGE, ESTABLISH SQL
TRIAL-N
4. COMPARE TRIALS & REVIEW SPA
REPORT, REMEDIATE
5. Deploy Change &
Tuning to PROD OR
further testing thru DB
Replay
Yes
DONE?
No
• Use Production or
identical Test System
• Test one change at a
time to understand
causality
• Reports show
deviations from
production
• Compare Baseline to
Trial-N in the same
environment
• For incremental tuning:
Compare Trial N-1 to
Trial-N
Usage Scenario: Evaluating Changes On
Production
Using SPA For Changes in Production: Example
Prod
+Add
And so on…
indexes
1. Fix Regression
thru SPM
Parameter change
was bad in this case
+Parameter
+Index
Change
Unusable
+New Stats
Change
+Validate
Fix Regression
SQL Profile
+Partitioning
Tuning
+SQL
Profile
• Bubble following the arrow indicates the
delta change on Production
• SPA is used for testing every change
How to Minimize Impact on Production?
• Generate Plan Vs Test Execute
– Use Generate Plan Trial Method to subset SQL with plan changes
– Only test execute SQL with plan changes
• Limit testing scope to private session or schema where possible
– Use alter session set <parameter> = <value>; (Vs system)
– Example usage for SQL Profiles:
• alter session set sqltune_category= ‘TEST’;
– Implement SQL Profiles and test Only sessions with “TEST” sqltune_category
see these Profiles - private scope!!
• alter session set sqltune_category= ‘DEFAULT’; -- Now SQL Profiles
visible globally to all sessions
• Similarly for Invisible Indexes, Pending Stats
• Use SPA time limit to control resource usage
• Test during maintenance window or non-peak activity when spare
resources are available
Using SPA on Production: Evaluating Optimizer
Statistics Refresh and other changes
Scenario:
Can I use SPA to check if any SQL statements
regressed due to optimizer statistics refresh on my
10.2/11g production databases? If so, how?
Goal:
Assess impact of optimizer statistics gathering
on SQL workload performance on production system
using SPA & make sure are no negative effects of the
change
Evaluating Optimizer Statistics Refresh
• Assumptions
–
–
–
–
Statistics refreshed periodically through custom jobs
No test system available, so evaluation is done on production
Should impact end-users minimally
Test using optimizer pending statistics feature
• Use SPA remote trials capability (generate plan and test execute)
to evaluate statistics refresh on 10.2/11g production database
• Analyze SPA report and take appropriate action
– Overall improvement but few SQL regressions
• Solution: Use SQL Profiles or Plan Management
– No improvement and many regressions
• Solution: Revert to old statistics: Use optimizer statistics
retention/history feature. Alternatively, configure optimizer
statistics appropriately*
– For Oracle Database 11g, “publish pending” statistics after evaluation
of statistics
OBE Tutorial on OTN: Gathering and Publishing Stats Independently
Using SPA on Production: Evaluating Optimizer
Statistics Refresh
Production Database (10.2/11g)
No Test Database Used!!
11g SPA System
Prod: Before Stats
Evaluate Opt Statistics Refresh
Remotely Build
SQL Trials
• No app
schema/data
necessary
• Not Mandatory for
11g db
Prod: Stats Refreshed
• Repository for
many tests!
1. Capture SQL workload to STS
2. Import STS
3. Gather Pending Stats
4. Use SPA to detect performance
changes
5. Publish Pending Stats and
Remediate Regressions
Usage Scenario:
End-to-End Case Study for 10.2  11g
Upgrade
10.2 11g DB Upgrade Using Enterprise Manager
Grid Control (EMGC) 10.2.0.5
Scenario:
I want to upgrade from 10.2 to 11g database release to
benefit from 11g functionality. How can I best accomplish the
upgrade?
Goal:
Assess impact of upgrade on SQL workload performance
using SPA so that there are no surprises after upgrade. Once
migrated to 11g new features can be enabled one at a time. Use
EMGC 10.2.0.5 for this purpose…
10.2  11g DB Upgrade
Production Database
Test Database
Prod DB (10.2)
Test DB (11g)
Upgrade
Upgrade
Test DB (10.2)
Send SQL for
Remote
Execution
1. Capture SQL
workload to STS
2. Transport STS
Collect
execution
stats
3. Establish 10.2 and 11g Trials
11g SPA System
5. Deploy Tuning and
Change to Prod
4. Compare performance and
generate SPA report
10.2  11g DB Upgrade
(1) Capture Workload to STS
Steps 1: Capture workload into STS through Incremental Capture
Workload into STS: Preferred method
Other sources for STS also possible: Top SQL in AWR / AWR
Baseline
10.2  11g DB Upgrade
(1) Capture Workload to STS
10.2  11g Upgrade
1. Capture SQL workload to STS
2. Transport STS
3. Establish 10.2 and 11g Trials
4. Compare performance and
Generate SPA report
5. Deploy Tuning and Change to
Prod
10.2  11g DB Upgrade
(2) Transport STS
Step 2:
• Copy STS to SPA system
• Setup Test DB (Copy of Prod) – 10.2
• Upgrade Test DB from 10.2 to 11g
10.2  11g DB Upgrade
1. Capture SQL workload to STS
2. Transport STS
3. Establish 10.2 and 11g Trials
4. Compare performance and
Generate SPA report
5. Deploy Tuning and Change to
Prod
10.2  11g DB Upgrade
(3) Establish 10.2 and 11g Trials
10.2  11g Upgrade
1. Capture SQL workload to STS
2. Transport STS
3. Establish 10.2 and 11g Trials
4. Compare Performance, Generate
SPA Report
5. Tune Regressions, Deploy
Tuning and Change to Prod
10.2  11g DB Upgrade
(4) Compare Performance and Generate Report
3
2
1
4
Note tuning/regression
fix is done on remote test
system that is being
upgraded
5
*
SPA Report
Regressed SQL Statements
10.2 11g Upgrade
1. Capture SQL workload to STS
2. Transport STS
3. Establish 10.2 and 11g Trials
4. Compare performance and
Generate SPA report
5. Tune Regressions, Deploy
Tuning and Change to Prod
10.2  11g DB Upgrade
(5) Regression Remediation
• If SPA system has application data/schema, tuning can be done
locally on the same DB
• If a separate SPA system is used, manually* subset SQL into a
separate STS and then use EM to transport it to remote DB
• Create SQL Plan Baselines: Helps revert to previously known,
stable plans
• SQL Tuning Advisor: Helps explore better execution plans
• All regressed SQL are targeted automatically for remediation
* Code snippet in Real Application Testing Users Guide (11.2), Chapter 11 Page 23
10.2  11g DB Upgrade
(5) Regression Remediation
10.2  11g DB Upgrade
(5) Deploy Tuning and Change in Production
10.2  11g Upgrade
1. Capture SQL workload to STS
2. Transport STS
3. Establish 10.2 and 11g Trials
4. Compare performance and
Generate SPA report
5. Tune Regressions, Deploy
Tuning and Change to Prod
Demo
SPA
SPA Enhancements in Oracle
Database 11g Release 2
SPA Enhancements: Oracle Database 11g Release 2
• Multiple test executes for better trial accuracy – first execution
ignored, averaged stats
• Alternate Plans: New recommendation added for regression
remediation
– If a better execution plan was noticed in AWR or baseline SQL Trial
then a SQL Plan Baseline can be created from it
• Active Reports
– New interactive, offline reports based on Adobe Flash Player UI
– Customers can share reports internally or with Oracle Support
• Save, email, View Reports
• Support can diagnose problems more efficiently
• Get EM UI without installing EM – useful for packaged apps and
internal development teams
– SPA Active Report Example
SPA Exadata Simulation: Estimating
Exadata Server Performance Gains
Predicting performance gains with SPA
•
Existing SPA and Database Replay functionality can be used to
compare non-Exadata to Exadata configurations
–
–
–
–
SPA: Unit test to find SQL response time gains
DB Replay: Stress test with concurrency to find throughput gains
Measure improvements for your workload
This approach requires you to provision Exadata HW
•
Oracle Database Release 11.1.0.7: Adds SPA functionality to
simulate Exadata on existing hardware to predict gains
•
Oracle Database Release 11.2: Adds SPA GUI support
•
Simulation measures reduction in I/O interconnect usage that
will in turn, reduce IO and CPU consumed on the DB server
SPA Exadata Simulation
Workflow
•
SPA Exadata Simulation builds two SQL Trials:
• Trial 1: Current configuration with No Exadata
• Trial 2: Current configuration with Exadata simulation
•
Comparison metric – I/O Interconnect Bytes
– Trial 1 value = I/O Interconnect (disk) bytes
– Trial 2 value is reduced depending on SQL operation
eligibility (for full table scans, index full scans, etc.)
– Plans will not change between trials
SPA Exadata Simulation Workflow
SPA Exadata Simulation: Report
SPA Report: SQL Details
Conclusion
• SPA provides comprehensive and easy-to-use
solution for SQL workload testing
• SPA can be used for many changes both test and
production environments
• Helps adopt technology faster by significantly cutting
down testing costs and production deployment risk
• With SPA and Real Application Testing businesses
can be stay competitive and improve profitability
Important Resources
Oracle Database Manageability
http://www.oracle.com/technology/products/manageability/database/index.html
Oracle Database 2-Day DBA Guide
http://download.oracle.com/docs/cd/E11882_01/server.112/e10897/toc.htm
Oracle Real Application Testing User’s Guide
http://download.oracle.com/docs/cd/E11882_01/server.112/e12254/toc.htm
SPA Active Reports
http://www.oracle.com/technology/products/manageability/database/sqlpa.html