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 10g Automatic 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

Automatic Workload Repository (AWR) 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

Automatic Workload Repository (AWR) 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 Plus Plus a lot of more Information

DBA_HIST_xxx Workload Repository V$xxx Statistics SGA Base Statistics, Metrics, SQL- Statistics,Active Session History Automatic Snapshots (Default 1h) “Historic” Data (Default 7 days) Automatic Space Management “Light Weight- Capture” MMON Internal Clients External Clients Automatic Workload Repository (AWR) -ADDM -Advisors -… Tsp: SYSAUX$ -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 Browse and Read Reviews Add item to cart Checkout using ‘ one-click ’ Active Session History (ASH)

DB Time Query for Novels Browse and Read Reviews WAITING State db file sequential readqa324jffritcf2137:38:26 EventSQL IDModuleSIDTime CPUaferv5desfzs5Get review id2137:42:35 WAITINGlog file syncabngldf95f4deOne click2137:52:33 WAITINGbuffer busy waithk32pekfcbdfrAdd to cart2137:50:59 Add item to cart Checkout using ‘ one-click ’ Book by author Active Session History (ASH)

Active Session History - Examples

ASH Report For PROD01/PROD011 DB Name DB Id Instance Inst Num Release RAC Host PROD PROD YES prodx005 CPUs SGA Size Buffer Cache Shared Pool ASH Buffer Size ,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

Active Session History - Examples Top User Events DB/Inst: PROD01/PROD011 (Feb 07 14:45 to 15:00) Avg Active Event Event Class % Activity Sessions enq: TT - contention Other CPU + Wait for CPU CPU enq: HW - contention Configuration 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 enq: TT - contention " ","14","16" name|mode tablespace ID operation " ","14","16" 11.79

Active Session History - Examples Top 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 , CPU + Wait for CPU PROD_APP00 DFSPCC20 834/900 [ 93%] , CPU + Wait for CPU PROD_APP00 DFSPCC20 833/900 [ 93%] , enq: TT - contention PROD_APP00 733/900 [ 81%] , enq: TT - contention PROD_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 SQL Tuning SQL Access Segment … AWR Unified Interface Integration Common Data Source

Automatic DB Diagnostic Monitor (ADDM) Part of Diagnostic Pack Automatic Diagnostic of performance problems Integrating all components Intelligent Infrastructure Application & SQL Management System Resource Management Space Management Backup & Recovery Management Storage Management 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 DBA High-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 Recommendations SQL 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/Linux Storage Management L Linux Guest 1 Linux Guest 2 Linux Guest n XSTOR The Bar Expanded Memory

Oracle 9.2 / 10g on z/Linux Storage Management L Linux Guest 1 Linux Guest 2 Linux Guest n XSTOR VM 5.2