Cognos 8 Arch and Tune

8/11/2019 Cognos 8 Arch and Tune

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This presentation was given at the September 2006 Chicago and Milwaukee Cognos User Group meetings

Copyright (C) 2006 Cognos, Inc Copyright (C) 2006 BrightStar Partners, Inc

Cognos 8Architecture and Tuning

Pascal Mouchakkaa

Cognos NA Services Domain Manager

Darek DanielewskiBrightStar Partners


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Copyright (C) 2006 Cognos Incorporated

While every attempt has been made to ensure that the information in this documentis accurate and complete, some typographical errors or technical inaccuraciesmay exist. Cognos does not accept responsibility for any kind of loss resultingfrom the use of information contained in this document.

This document shows the publication date. The information contained in thisdocument is subject to change without notice. Any improvements or changes toeither the product or the document will be documented in subsequent editions.

U.S. Government Restricted Rights. The software and accompanying materials areprovided with Restricted Rights. Use, duplication, or disclosure by theGovernment is subject to the restrictions in subparagraph (C)(1)(ii) of the Rights

in Technical Data and Computer Software clause at DFARS 252.227-7013, orsubparagraphs (C) (1) and (2) of the Commercial Computer Software - RestrictedRights at 48CFR52.227-19, as applicable. The Contractor is Cognos Corporation,67 South Bedford Street, Burlington, MA 01803-5164.


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This software/documentation contains proprietary information of CognosIncorporated. All rights are reserved. Reverse engineering of thissoftware is prohibited. No part of this software/documentation may becopied, photocopied, reproduced, stored in a retrieval system,transmitted in any form or by any means, or translated into another

language without the prior written consent of Cognos Incorporated.Cognos, the Cognos logo, Cognos 8, Cognos ReportNet, Axiant,

COGNOSuite, Cognos Upfront, Cognos DecisionStream, Impromptu,NoticeCast, PowerCube, PowerHouse, PowerPlay, Scenario, and4Thought are trademarks or registered trademarks of CognosIncorporated in the United States and/or other countries. All other

names are trademarks or registered trademarks of their respectivecompanies.

Information about Cognos Products and Accessibility can be found atwww.cognos.com


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Agenda

Architecture Overview

C8 Components Architecture Tier Architecture

Request Flow

Logging and 3rd Party Monitoring Solutions

Proven Practices for Tuning

Server JVM Heap and Garbage Collection

Thread and Queue

System/Server

Web Server

Data Base

Report/Model

Local Processing Metadata Caching and Callbacks

Minimized SQL

Parameter Maps

Prompting

Q&A


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Cognos 8 System Architecture


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Web Tier Components

Gateway shuttles requests for Cognos 8 services to and

from dispatcher and relays results to Browser

CGI, ISAPI, Apache Mod, Servlets for iPlanet/Sun One

Avoid CGI unless only supported gateway for Web server

Supports standard TCP/IP sockets or SSL

Single sign-on and SSL


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Application Tier Components

Multi-threaded, distributable components

Multi-platform

Multi Application server

Responsible for dynamically loading services and handlers

Routes requests to Content Manager, Reporting Service,Audit and Presentation/Notification Service

Registers itself in Content Manager at startup, identifies

services it provides

Load balance and fail over

No single point of failure, no single master node


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Content Manager (Application Tier)

Centralizes report and configuration information

Content Store

All definitions, output, content folders, metadata

Results stored in compressed form

Standby capability

Leverages existing RDBMS investment

Oracle and Oracle RAC, DB2, Microsoft SQL Server Windows and SQL

authentication, and Sybase

RDBMS responsible for backup/recovery and tolerance

Connects to RDBMS using JDBC thin client

Responds to requests from Dispatcher services


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C8 Request Flow in Distributed Environment

How do I know where my

request will end up?


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Log View Tool

Built in tool to assist in Log analysis.

Can filter out Cognos 8 errors or focus on component

messaging.


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3rd Party Solutions for Monitoring ProductionEnvironment Performance

Teleran Technologies

i-Guard is a solution to prevent problematic queries, i.e. in ad-hoc

environment

i-Sight is a solution to analyze queries and data access

BI Application Extensions allow collecting Cognos-specific metrics,SQL and performance information

AppFluent Technology

Query Performance is a solution to analyze queries and data access

Query Testing is a solution to identify broken queries

Compliance Audit is a solution to log users accessing specific data

Both solutions only support relational data sources


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Agenda



Request Flow




Thread and Queue

System/Server

Web Server

Data Base

Report/Model


Minimized SQL

Parameter Maps

Prompting

Q&A


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JVM and Garbage Collection

Java Heap will allocate memory required to run and clear

Container

The larger the heap the longer it takes to clear memory

(Garbage Collection) JRE and version determines method of collection at runtime

Recommended Proven Practices are to set heap no larger

than 1024MB


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JVM Multiple Instance

Due to OS Stack memory constraints of 2048MB per running

process.

With systems that have large physical memory cache.

Requires multiple installation of components or clusteringcapability.


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Thread and Queue Tomcat

Limits all Thread execution within JVM Container.

Tomcat predefined is set to 500 in server.xml.

Accept Queue limits amount of threads to queue

Tomcat predefined is set to 500 in server.xml.


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System Tuning

Report Service (interactive usage)

Maximum processes: 2 per processor

High affinity connections: 1 per process

Low affinity connections: 4 per process

No more than 5 per process

Batch Report Service (non-interactive usage)

Same guidelines as above

Remember to set Peak Periods


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Thread and Queue Web Sphere

Thread allocation

Change Max size to 2.5 threads * # of concurrent users

Check Is Growable


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Server Tuning

Unix: HP, AIX, Solaris, and Linux

Cognos 8 patch set following Cognos recommended CONFORMANCE

Permissions

Disk Space

Kernel Parameters and Environment variables

Windows: Registry entries for OS heap size and high load capacityunder HKEY_LOCAL_MACHINE

SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\TCPTimedWaitDelay=30s (default 240s)

SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\MaxUserPort=10000or higher (default = 5000)

SYSTEM\CurrentControlSet\Control\SessionManager\SubSystem\Windowsshared section set to 1024 to 3072 in KB (default = 512)


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Web Server

IIS 5/6 compression.

Use Performance Monitor Tools. If % of Processor Time is greater

than 80% consistently, Dont compress, upgrade Server

HTTP Compression can reduce Web Server file size traffic 30-50%.

Increase download time.

HTTP Compression requires additional Hard Drive Space and CPU

Cycles

Apache tuning is subject to OS and compile method.

Windows default is worker threads

Unix default is prefork


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Data Base

Changes to the CogdmXX.ini must be tested on reasonable volumes of

data and the execution plan examined before and after any changes to

ensure that the changes will improve performance rather than harm it.

Oracle Changes for example:

Oracle Case vs. Decode. Using DECODE may improve performance.Change case_to_decode in Cogdmor.ini to T

Removing an Oracle sub query to a nested inner-join may improve

performance. Change the NESTED_INNER to T in the Cogdmor.ini and

modify the processing location to Database only.

Use Oracle optimization techniques for join strategies. Oracle Optimizer willstill join one at a time. List joins in proper order. Smallest table first.

Calculate and validate statistics on data changes.


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Agenda



Request Flow




Thread and Queue

System/Server

Web Server

Data Base

Report/Model


Minimized SQL

Parameter Maps

Prompting

Q&A


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Identify Local Processing

Is local processing required?

Set processing to Database Only and test query

What is being processed locally and what is processed on

the database? Compare Cognos SQL to Native SQL in Report Studio or FM

How much data is brought to process in the app tier?

Monitor the C8 temp directory when running reports

Watch for files with uda prefix these are temp. files

Everything above 8Mb (UDA temp memory buffer) is written to a

temp file


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Example UDA Temp Files


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Heterogeneous Query

Two or more data sources (not just catalogs) joined in FM model

Introduces local processing compare Cognos SQL to Native

Cognos

select SALES_BRANCH.ADDRESS1 as Address, SALES_BRANCH.CITY as City,

SALES_BRANCH.REGION as Region, COUNTRY.COUNTRY_EN asCountry_Name from gosales.GOSL_C8.dbo.SALES_BRANCH SALES_BRANCH

join goretailers.gort.dbo.COUNTRY COUNTRY on (COUNTRY.COUNTRY_CODE =

SALES_BRANCH.COUNTRY_CODE)

Native

select "SALES_BRANCH"."ADDRESS1", "SALES_BRANCH"."CITY",

"SALES_BRANCH"."REGION", "SALES_BRANCH"."COUNTRY_CODE" from"GOSL_C8"."dbo"."SALES_BRANCH" "SALES_BRANCH" order by 4 asc select

"COUNTRY"."COUNTRY_EN", "COUNTRY"."COUNTRY_CODE" from

"gort"."dbo"."COUNTRY" "COUNTRY" order by 2 asc

Full data sets retrieved on both sides, then joined locally


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Avoiding Heterogeneous Query

Same database but different catalogs - reuse the same CM

connection name to avoid local processing


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Avoiding Heterogeneous Query Contd.

Cognos SQL

select SALES_BRANCH.ADDRESS1 as Address, SALES_BRANCH.CITY as

City, SALES_BRANCH.REGION as Region, COUNTRY.COUNTRY_EN as

Country_Name from gosales.GOSL_C8.dbo.SALES_BRANCH

SALES_BRANCH join gosales.GORT_C8.dbo.COUNTRY COUNTRY on

(COUNTRY.COUNTRY_CODE = SALES_BRANCH.COUNTRY_CODE)

Native SQL

select "SALES_BRANCH"."ADDRESS1" AS "Address",

"SALES_BRANCH"."CITY" AS "City", "SALES_BRANCH"."REGION" AS

"Region", "COUNTRY"."COUNTRY_EN" AS "Country_Name" from

"GOSL_C8"."dbo"."SALES_BRANCH" "SALES_BRANCH" INNER JOIN"GORT_C8"."dbo"."COUNTRY" "COUNTRY" on

"COUNTRY"."COUNTRY_CODE" = "SALES_BRANCH"."COUNTRY_CODE

Native SQL now contains only one Select statement


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Metadata Caching

Stores information on data items and query subjects in the

model.

In most cases information captured by metadata import,

cached with FM model and reused at run-time

Eliminates the need to lookup information from the

database

Allows for faster preparation and validation of query SQL


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Metadata Callbacks When Running Reports

Report Studio Validate with Options / FM Query Information

Thi t ti i t th S t b 2006 Chi d Mil k C U G ti


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RS Validation Output

Shared Dimensions listed for a multi-fact queries

QE-DEF-0469 QE Message RQP-DEF-0433 Shared Dimensions:

[Product dimension].[Product line]

[Product dimension].[Product type]

[Product dimension].[Product dimension]

Metadata Queries listed for specific tables

QE-DEF-0469 QE Message RQP-DEF-0543

Metadata will be retrieved from the database, because a

simple DB query subject definition with matching

metadata does not exist. database='go_data_warehouse'catalog='GOSLDW' schema='dbo' table='PRODUCT_LINE

Cognos and Native SQL included

Review Output File (validation messages.xml)



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Metadata Callbacks

When does C8 have to retrieve metadata at run-time? Changes to imported data source query subjects:

More than one table in the query

More than one select statement

Embedded filters

Embedded calculations Prompts and parameter maps

Hand-written SQL

Enhanced Model Portability option forces metadata callbacks

What can you do to reduce metadata callbacks?

Create a new namespace and import all tables as is

In FM, evaluate and update query subjects in question

Disable the enhanced portability governor

Reference model objects in model query subjects



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Minimized SQL

C8 will attempt to minimize SQL it sends to RDBMS

Makes it easier to leverage aggregated views (i.e. MV)

Example 1:

SELECT ColumnA, SUM(ColumnB)

FROM TableA

GROUP BY ColumnA

Example 2:

SELECT ColumnA, MIN(ColumnC), SUM(ColumnB)FROM TableA

GROUP BY ColumnA, ColumnC



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Minimized SQL Database Optimizers

Original Statement

SELECT T1.ColumnA, T1.ColumnB

FROM (

SELECT ColumnA ColumnA,

MIN(ColumnC) ColumnC,SUM(ColumnB) ColumnB

FROM TableA

GROUP BY ColumnA) T1

Functionally Equivalent

SELECT ColumnA, SUM(ColumnB)

FROM TableA

GROUP BY ColumnA



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When C8 Minimizes SQL?

Minimized by definition

Data source query subject are the lowest level SQL building blocks

Eligible for Minimization

Model query subjects with no relationships or determinants

Model regular and measure dimensions

Not Eligible for Minimization

Model query subjects with relationships and/or determinants

Hand-written SQL will not be minimized

Embedded prompts are evaluated at run-time and not minimized



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Parameter Maps

Allow incorporating session information, user locale and

prompt selections logic to augment model behavior

When using parameter maps be aware that:

Parameter map entries are strings rather then object references Cannot validate all parameter map entries with a single test

Very large, nested parameter maps need to be parsed at runtime and

increase SQL prepare cost

Using parameter maps prevents SQL minimization and metadata

caching



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Parameter Maps Proven Practices

Leave data source query subjects unmodified whenever

possible

Build model calculations and filters on data source query

subjects (not embedded)

Embed model calculations and filters in model query

subjects and/or dimensions

Avoid large, nested parameter maps whenever possible

Evaluate whether a prompt or parameter map is appropriatein the model rather than in a report design technique



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Prompt Performance General Considerations

Look at the overall report spec, not just the prompt

Report spec needs to be parsed, SQL generated in order to determine what

prompts to present to the user

Do you have too many queries on a prompt page?

Split prompts across multiple pages

How much data do your prompt queries return?

Cost of sending thousands of rows to the browser and rendering is often

overlooked

Can a user skip optional prompts?

Position optional prompts towards the end of the wizard, so users have anoption to hit Finish and go directly to the report

Do you have too many prompts?

Case I came across included drill-through report designed to handle any

possible context in a cube



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C i ht (C) 2006 C I C i ht (C) 2006 B i htSt P t I

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Cognos 8 Arch and Tune