1. Kurt Engeleiter Product Manager Database Manageability
DBA’s New Best Friend: Oracle Database 10g and 11g SQL Performance Analyzer
Kurt Engeleiter
Product Manager
Database Manageability

2. SQL Performance Analyzer (SPA) – Introduction
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

3. 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

4. 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
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
SQL Workload
STS
SQL plans + stats
SQL plans + stats
Pre-change Trial
Post-change Trial
Compare
SQL Performance
Analysis Report

5. 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 Trials do not alter the data. Therefore, SPA is amenable for testing some changes in production

6. SPA: Common Usage Scenarios
Database upgrades and patch-set releases
9.2/10.1 10.2 or 11g releases
x  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:

7. SPA: Enterprise Manager Interface
Rich GUI through Enterprise Manager – New workflows added!
DBMS_SQLPA package PL/SQL API
New Workflows !

8. Recommended Testing Methodology

9. 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

10. Recommended Testing Methodology with SPA
1. CAPTURE REPRESENTATIVE SQL WORKLOAD TO STS
Use Production or identical Test System
Test one change at a time to understand causality
2. ESTABLISH BASELINE (SQL TRIAL-1) WITHOUT CHANGE
Reports show deviations from production
3. MAKE CHANGE, ESTABLISH SQL TRIAL-N
Compare Baseline to Trial-N in the same environment
For incremental tuning: Compare Trial N-1 to Trial-N
4. COMPARE TRIALS & REVIEW SPA REPORT, REMEDIATE
5. Deploy Change & Tuning to PROD OR further testing thru DB Replay
Yes
DONE? No

11. Usage Scenario: Evaluating Changes On Production

12. Using SPA For Changes in Production: Example
+Add
indexes
And so on…
Parameter change was bad in this case
1. Fix Regression thru SPM
+Index
Unusable
+Parameter
Change
+New Stats
Change
+Validate
Tuning
+Partitioning
Fix Regression SQL Profile
+SQL
Profile
Bubble following the arrow indicates the delta change on Production
SPA is used for testing every change

13. 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

14. 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

15. 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

16. Using SPA on Production: Evaluating Optimizer Statistics Refresh
Production Database (10.2/11g)
No Test Database Used!!
11g SPA System
Prod: Before Stats
No app schema/data necessary
Not Mandatory for 11g db
Repository for many tests!
Remotely Build SQL Trials
Evaluate Opt Statistics Refresh
Prod: Stats Refreshed
Capture SQL workload to STS
2. Import STS
3. Gather Pending Stats
Use SPA to detect performance changes
5. Publish Pending Stats and Remediate Regressions

17. Evaluating Optimizer Statistics Refresh
Tips!
On production, first use SPA to generate execution plans only, then test-execute SQLs with changed plans
If you’re creating remote trials, you will need a logon trigger to set optimizer_use_pending_statistics = TRUE private to the second trial (SPA establishes the connection itself, over db link, so you cannot run alter session yourself)
To test-execute only those SQLs with changed plans, subset your STS after doing trial 2, then do a new SPA experiment on that STS
Script to subset STS is on Notes slide
Note: this matches the script for subsetting an STS found in the Performance Tuning Guide, Chap 11, except that here we select SQLs with changed plans (‘8’ bit) rather than regressed SQLs (‘2’ bit)
DECLARE
tname varchar2(100);
exec_name varchar2(100);
dest_sts varchar2(100);
sqlset_cur DBMS_SQLTUNE.SQLSET_CURSOR;
src_sts varchar2(100);
src_sts_own varchar2(100);
BEGIN
tname := 'SPA_TASK1';
exec_name := 'COMP';
dest_sts := 'SUB_STS1';
src_sts := 'FULL_STS';
src_sts_own := 'IMMCHAN';
DBMS_SQLTUNE.CREATE_SQLSET(dest_sts, 'test purpose');

18. Usage Scenario: End-to-End Case Study for 10.2  11g Upgrade

19. 10. 2 11g DB Upgrade Using Enterprise Manager Grid Control (EMGC) 10
Scenario:
I want to upgrade from 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 for this purpose…

20. 10.2  11g DB Upgrade Upgrade Send SQL for Remote Execution
Production Database
Test Database
Prod DB (10.2)
Test DB (11g)
Upgrade
Collect execution stats
3. Establish 10.2 and 11g Trials
4. Compare performance and generate SPA report
Send SQL for Remote Execution
Upgrade
Test DB (10.2)
2. Transport STS
Capture SQL workload to STS
11g SPA System
5. Deploy Tuning and Change to Prod

21. 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

22. 10.2  11g DB Upgrade (1) Capture Workload to STS

23. 10.2  11g Upgrade 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

24. 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

25. 10.2  11g DB Upgrade 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

26. 10.2  11g DB Upgrade (3) Establish 10.2 and 11g Trials

27. 10.2  11g Upgrade 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

28. 10.2  11g DB Upgrade (4) Compare Performance and Generate Report3
Note tuning/regression fix is done on remote test system that is being upgraded 2 5* 1 4

29. SPA Report Regressed SQL Statements

30. 10.2 11g Upgrade 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

31. 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

32. 10.2  11g DB Upgrade (5) Regression Remediation

33. 10.2  11g DB Upgrade (5) Deploy Tuning and Change in Production

34. 10.2  11g Upgrade 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

35. Demo
SPA

36. SPA Enhancements in Oracle Database 11g Release 2

37. 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, , 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

38. SPA Enhancements: Oracle Database 11g Release 2 Using SPA With Other Testing Tools – Build Trials from STS
Allows comparing two different STS and generate SPA report
Eliminates re-executing SQL for trial data
Performance statistics picked up from the STS
Multiple plans even those with different binds/env picked up for comparison
Use cases: Perform SQL-centric analysis
Database Replay
SQL workload capture into STS-1 during Database Replay - Workload Capture
STS-2 during Database Replay – Workload Replay
Use SPA to build trials from STS-1 and STS-2 and generate report
Similarly with Oracle Application Testing Suite or home-grown scripts
Reporting: SPA Report + Additional information
Common SQL, Missing/New SQL, Plan Changes
Overall Workload and Individual SQL Statistics
Available in 11.2 database release, API only

39. SPA Exadata Simulation: Estimating Exadata Server Performance Gains

40. 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 : 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 40

41. 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 41

42. SPA Exadata Simulation Workflow

43. SPA Exadata Simulation: Report

44. SPA Report: SQL Details

45. 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

46. Oracle Database Manageability
Important Resources
Oracle Database Manageability
Oracle Database 2-Day DBA Guide
Oracle Real Application Testing User’s Guide
SPA Active Reports