oracle 10.2 for z/os and z/linux performance update

Oracle 10.2 for z/OS and z/Linux

Performance Update

Agenda

• Introduction• Tuning – Why• Diagnosis

• Statspack• Oracle 10g Automatic Workload Repository(AWR)

• Oracle 10.2 Features• AWR - Enhancements• ASH• Workload Repository compare Report

• Oracle 10g Advisors • Miscellaneous

• z/OS - WLM• VM

Why do we need to tune ?

• Users report „bad“ response times because of

• CPU Time + Wait Time

• Poor performing queries • SQL-Tuning

• „bad“ database parameters

• Bottlenecks in „system“ (Operating system, WLM, IO/Subsystem etc.)

Diagnostics

Statspack – a short overview

spcreate.sql - installs Statspack (run only once)

statspack.snap - data capture (procedure)

spreport.sql - reporting

spdoc.txt - user documentation

sppurge.sql - delete Statspack data

spdrop.sql - drop Statspack

Statspack – Content

Environment Section

Load Profile

Instance Efficiency

Top 5 Timed Events

TOP SQL

I/O Statistics

Oracle 10gAutomatic Workload Repository

(AWR)

Automatic Workload Repository (AWR)

• Automatically collects database instance statistics

• An “automated” STATSPACK with less overhead and enhanced functionality • On by default in Oracle Database 10g

• Stores data in SYSAUX tablespace

• Provides DBA_HIST (historical) views


• Automatically collects database instance statistics

• Licensed in the Diagnostics Packs

• Captures statistical data• Used by

• AWR-Reports • Oracle database advisors • self-management features• Coordinated across RAC instances


• Text and HTML Version available

• Reports can be generated / viewed by

• OEM• Scripts

• awrrpt.sql• awrrpti.sql• ashrpt.sql (10.2)• awrddrpt.sql(10.2)

• Contains information comparable to Statspack• PlusPlus a lot of more Information

DBA_HIST_xxx

Workload

RepositoryV$xxx

Statistics

SGA

• Base Statistics, Metrics, SQL-Statistics,Active Session History

• Automatic Snapshots (Default 1h)

• “Historic” Data (Default 7 days)

• Automatic Space Management

• “Light Weight-Capture”

MMON

Internal Clients

External Clients


-ADDM-Advisors-…

Tsp: SYSAUX$

-SQL*PLUS-EM-…

Oracle 10g SQL Statistics

• SQL_id – unique hash value• SQL statement statistics

• Wait class time• PLSQL time• Java time

• Sampled bind values (v$sql_bind_capture)• Default=900

• Efficient top SQL identification using Δs in the kernel, by 6 dimensions:

• CPU• Elapsed• Parse• ...

Active Session History (ASH)

Sampled history of v$session_wait

• Samples active sessions every second into memory (v$active_session_history)

• Direct access to kernel structures• Selected samples flushed to AWR• Data captured includes:

• SID • SQL ID• Program, Module, Action • Wait event# • Object, File, Block• actual wait time (if captured while waiting)

Active Session History• Part of AWR

• Helps to analyze

• Short term problems (minute history)• Isolation of the cause by SQL_ID, SESSION_ID, MODULE etc.• Blocking Sessions (Enqueue, buffer busy wait)

• Called by• ASH Report (ashrpt.sql or Enterprise Manager)• Hang Analyze

DB Time

Query for Novels

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DB Time

Query for Novels

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WAITING

Statedb file sequential readqa324jffritcf2137:38:26

EventSQL IDModuleSIDTime

CPUaferv5desfzs5Get review id2137:42:35

WAITING log file syncabngldf95f4deOne click2137:52:33

WAITING buffer busy waithk32pekfcbdfrAdd to cart2137:50:59

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Active Session History - Examples


ASH Report For PROD01/PROD011

DB Name DB Id Instance Inst Num Release RAC Host------------ ----------- ------------ -------- ----------- --- ------------PROD01 2608917897 PROD011 1 10.2.0.2.0 YES prodx005

CPUs SGA Size Buffer Cache Shared Pool ASH Buffer Size---- ------------------ ------------------ ------------------ ------------------ 4 8,192M (100%) 6,224M (76.0%) 1,899M (23.2%) 8.0M (0.1%)

Analysis Begin Time: 07-Feb-07 14:45:21 Analysis End Time: 07-Feb-07 15:00:21 Elapsed Time: 15.0 (mins) Sample Count: 6,215 Average Active Sessions: 6.91 Avg. Active Session per CPU: 1.73 Report Target: None specified


Top User Events DB/Inst: PROD01/PROD011 (Feb 07 14:45 to 15:00)

Avg ActiveEvent Event Class % Activity Sessions----------------------------------- --------------- ---------- ----------enq: TT - contention Other 47.59 3.29CPU + Wait for CPU CPU 43.56 3.01enq: HW - contention Configuration 4.39 0.30 -------------------------------------------------------------

Top Background Events DB/Inst: PROD01/PROD011 (Feb 07 14:45 to 15:00)

No data exists for this section of the report. -------------------------------------------------------------

Top Event P1/P2/P3 Values DB/Inst: PROD01/PROD011 (Feb 07 14:45 to 15:00)

Event % Event P1 Value, P2 Value, P3 Value % Activity------------------------------ ------- ----------------------------- ----------Parameter 1 Parameter 2 Parameter 3-------------------------- -------------------------- --------------------------enq: TT - contention 47.59 "1414791172","14","16" 35.80name|mode tablespace ID operation

"1414791174","14","16" 11.79

Active Session History - ExamplesTop Sessions DB/Inst: PROD01/PROD011 (Feb 07 14:45 to 15:00)-> '# Samples Active' shows the number of ASH samples in which the session was found waiting for that particular event. The percentage shown in this column is calculated with respect to wall clock time and not total database activity.-> 'XIDs' shows the number of distinct transaction IDs sampled in ASH when the session was waiting for that particular event-> For sessions running Parallel Queries, this section will NOT aggregate the PQ slave activity into the session issuing the PQ. Refer to the 'Top Sessions running PQs' section for such statistics.

Sid, Serial# % Activity Event % Event--------------- ---------- ------------------------------ ----------User Program # Samples Active XIDs-------------------- ------------------------------ ------------------ -------- 1067,10368 13.44 CPU + Wait for CPU 13.42PROD_APP00 DFSPCC20 834/900 [ 93%] 0

1059,30273 13.42 CPU + Wait for CPU 13.40PROD_APP00 DFSPCC20 833/900 [ 93%] 0

1052,36644 12.98 enq: TT - contention 11.79PROD_APP00 733/900 [ 81%] 0

1055, 3522 12.87 enq: TT - contention 11.79PROD_APP00 733/900 [ 81%] 0

Workload Repository Compare Report

Oracle 10g Advisors

Advisors : Overview

ADDM

SQL Tuning

SQL Access

Space

Mttr

Undo

Memory

PGA

SGA

Buffer Cache

Shared Pool

Segment

Obsolete if using SGA_TARGET

• Self optimizing PGA• PGA_AGGREGATE_TARGET

• Self optimizing SGA• SGA_TARGET

sort

PGA Pool

sort

PGA Pool

SQL Cache

Online

Buffer Cache

Java Pool

SGA Pool

Batch

Java Pool

SQL Cache

Buffer Cache

SGA Pool

SGA_TARGET

Advisors: Integration

Advisor Infrastructure

ADDM SQLTuning

SQLAccess

Segment …

AWR

UnifiedInterface

Integration

Common

Data Source

Automatic DB Diagnostic Monitor (ADDM)

• Part of Diagnostic Pack• Automatic Diagnostic of

performance problems• Integrating all components

Intelligent Infrastructure

Application & SQLManagement

System ResourceManagement

SpaceManagement

Backup & RecoveryManagement

StorageManagement

Database Management

Proactive and effective tuning

ADDM - Overview

• Database-wide performance diagnostics, including RAC

• Tuning Metric: Reduce DB-Time • Throughput centric, top down• Root Causes with impacts

• Differentiation of causes and symptoms

• Actionable, detailed recommendations with benefit• Runs automatically every hour (AWR-Snap) or manually• May recommend calling other advisors

SQL Tuning Advisor: Automatic SQL Tuning

I can do it for you !

SQL Tuning Advisor

DBAHigh-Load

SQL

ADDM

SQL

Workload

Automatic SQL Tuning Overview

Add Missing Indexes

Modify SQL Constructs

Create a SQL Profile

Automatic Tuning Optimizer

SQL Structure Analysis

Access Path Analysis

SQL Profiling

Statistics Analysis

Gather Missing or Stale Statistics

DBA

SQL Tuning

RecommendationsSQL Tuning

Advisor

Automatic Tuning Optimizer (ATO)

It is the query optimizer running in tuning mode– Uses same plan generation process but performs

additional steps that require lot more time

It performs verification steps– To validate statistics and its own estimates

Uses dynamic sampling and partial executions

It performs exploratory steps– To investigate the use of new indexes that could

provide significant speed-up– To analyze SQL constructs that led to expensive

plan operators

Miscellaneous

z/OS WLM• Everything works fine without peaks (e.g.CPU

30%)• Common Problems we had with WLM(during

peak periods) • The „Everything is important syndrom“

• User didn´t classify any discretionary goals• Everything had the same importance

• Enclave(Sess) with response time goals

• Enclave goes to last period (which was discretionary) shortly after Logon

• No default service class for OSDI

• Mistake in classification rules will result in SYSOTHER being used – discretionary goal

Oracle 10g on z/Linux

• Async-I/O

- Process passes I/O-request to OS- work is processed in parallel- OS sends an interrupt when the work is finished

• Direct-I/O

- Unix Filesystem Buffer Cache is not used- no double buffering

Oracle 10g on z/Linux

Async I/O changes on init.ora.

•Raw devices

- DISK_ASYNCH_IO = TRUE

•Filesystem

- FILESYSTEMIO_OPTIONS=ASYNC - FILESYSTEMIO_OPTIONS=SETALL

Async I/O + Direct I/O

Oracle 9.2 / 10g on z/LinuxStorage Management

L

Linux Guest 1

Linux Guest 2

Linux Guest n

XSTOR

The Bar

Expanded Memory

Oracle 9.2 / 10g on z/LinuxStorage Management

L

Linux Guest 1

Linux Guest 2

Linux Guest n

XSTOR

VM 5.2

oracle 10.2 for z/os and z/linux performance update

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