Oracle BI Suite Enterprise Edition “Advanced” RPD Modelling BI EE... · Oracle BI Suite...

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Oracle BI Suite Enterprise Edition

Optimising BI EE using Oracle OLAP and Essbase

Antony Heljula

Technical Architect

© Peak Indicators Limited 2

Agenda

Overview

When Do You Need a Cube Engine?

Example Problem : Project DW

Oracle OLAP Demonstration

Oracle Essbase Demonstration

Performance Test

Summary


Overview


Overview

Oracle has two well-established “cube” engines in its product line:

Oracle OLAP

Oracle Essbase

Whilst they are architecturally and functionally quite different, they both offer significant potential for optimising your BI infrastructure

This presentation does not aim to give a detailed feature comparison, but instead to demonstrate from a “solutions architecture” point of view as to:

1. When a cube engine might be of benefit to you

2. How each of the two engines can be most effectively used and integrated with Oracle BI EE

We shall be looking at versions Oracle OLAP 11g and Oracle Essbase 11.1.1.1.1


When do you need a Cube Engine?



Relational Data-Warehouses contain features that offer significant performance improvements compared to an OLTP:

Star-Schema Transformation

Materialized Views / Aggregate Tables

Hierarchy Tables

Denormalisation

Mini-Dimensions

Bitmap Join indexes

etc

BI Tools also have features that can provide further optimisation:

BI Server Caching

BI Presentation Services Caching

Aggregate Navigation

Fragmentation

etc



Sometimes however, data volumes or reporting complexity are such that the level of “optimisation” required goes beyond manageable levels

Oracle BI

MVs



A Cube Engine’s calculation performance is so superior you can sometimes replace the complexity with just a single Cube

Oracle BI

OLAP

Essbase


Example Problem : Project DW


Overview of Problem

Project Data-Warehouse contains a simple “Expenditure Items”star-schema:

3 Measures

5 Dimensions


Overview of Problem

And we have a simple dashboard providing a week/month overview of:

Expenses

Labour (Effort)

Project Margin


Overview of Problem

We have the following factors to consider:

The central fact table stores >5 million records per year

Managers need to report by Week as well as at higher levels of summary

Security implemented as reasonably low level of granularity:

Project Managers can only see data relating to their Projects

Resource Managers can only see data relating to their Resources

So, this means:

Large volumes of data

Reporting required at both low and high levels of summary

Security applied at low level of granularity


Steps Already Taken

Two levels of MVs already created to:

Reduce the number of dimensions

Aggregate to Week and Month levels

Day Level:5M Recordsper year

Week Level:1.7M Recordsper year

Month Level0.5M Recordsper year


But...

With only 1 year’s worth of data and one dashboard, there are already concerns around scalability:

Reporting performance not sustainable in the long term

Need at least 3 levels of summary to achieve anything like acceptable scalability for summary reports

Reporting performance at Week level is still poor though, will significantly degrade over time

Already experiencing scalability issues when multiple users run reports concurrently


Possible Options

Usually the following options are considered: Leverage BI Server caching

Suitable for top-level dashboards only, so not drill-down reports

Create more Materialized Views New MV at Quarter level

Create new MVs dedicated Resource Managers (for reporting at Week level)

Create new MVs dedicated to Project Managers (for reporting at Week level)

Table Partitioning Perhaps at Quarter / Year levels

Not all reports will benefit from “partition elimination”

Purchase additional hardware Increase database memory

Add more CPUs

Stripe database over more disks


Where Are We Heading?

5+ MVs required per Dashboard / Star

Performance is poor for newly created reports (need to wait for a dedicated MV to be created)

Reduced flexibility

Frustration for the report writers

Infrequent roll-out of reports

Slow end-user adoption

Increasing hardware costs

Oracle BI

MVs


What about OLAP or Essbase?

Let’s see if Oracle OLAP / Essbase cubes can help rectify the situation

We are going to see if a single OLAP / Essbase cube will be enough to cater for all our reporting requirements

Ideally what we are looking for is: Performance and scalability with our existing hardware

Decent performance when reporting at low and high levels of summary

Reduced development effort

Less ETL maintenance and administration

Minimal impact to the existing implementation


Oracle OLAP


Oracle OLAP

Oracle OLAP is a calculation engine embedded within the Oracle Database

OLAP cubes and dimensions accessed via SQL interface

No separate servers, users or file systems to manage

Applications can seamlessly switch between Relational and OLAP queries

Oracle Database


Oracle OLAP

There are currently two possible mechanisms through which BI EE can leverage the power of Oracle OLAP engine:

Relational Views (“Cube Views”)

Cube Organized Materialized Views (new with Oracle Database 11g)

Both mechanisms have their pros and cons

Integration with BI EE


Oracle OLAP

Relational Views (“Cube Views”)

A layer of database Relational Views are created on top of the OLAP cube

By querying the Relational Views directly, BI EE can leverage all the OLAP features available

The Relational Views are created automatically

Although the reporting experience is seamless for the end-user, modelling the BI Repository is not easy (so recommended only for “small” cubes)

Integration via Relational Views

Oracle Database

Oracle BI


Oracle OLAP

Reporting via Relational Views is not easy to implement in Oracle BI EE due to the “level filters” that need to be included in each SQL statement

Due to the complex modelling and development overhead required, this approach is suitable if you have relatively small number of Dimensions and Hierarchy Levels to model (e.g. 4 Dimensions with no more than 4 Hierarchy Levels)

A tutorial available on OTN : http://www.oracle.com/technology/obe/olap_biee/CreateBIEEMetadata.htm

Integration via Relational Views

SELECT ……

FROM expense_cubeview

WHERE CATEGORY_LEVEL = ‘TOTAL_CATEGORY'

AND TIME_LEVEL = ‘QUARTER'

AND ORG_LEVEL = ‘ORG LEVEL 2’

AND ORG_LEVEL2_DESC IN ('Northeast Region‘,

'Western Region')

NOTE: We need to include the “Category” level filter even though this dimension is not in the actual report

http://www.oracle.com/technology/obe/olap_biee/CreateBIEEMetadata.htm


Oracle OLAP

Cube Organized Materialized Views (new with Oracle Database 11g) The OLAP cubes are presented as “Materialized Views” and therefore benefit from key

MV features such as Fast Refresh, Query Rewrite and Management of Stale Data

BI EE can take advantage of the “Query Rewrite” feature, where the Oracle Database will automatically rewrite standard relational queries to source from the OLAP cubes

Although this approach requires minimal development effort, not all relational queries are candidates for Query Rewrite and you cannot use any calculations defined in the OLAP cube itself

Integration via Query Rewrite

Oracle Database

Oracle BI

Rewrite


Oracle OLAP

Demonstration



Oracle OLAP

This approach is best suited to the following situations: Performance optimization is required on an Oracle Database / Data-Warehouse

The queries involved only use SUM, MAX, MIN functions

BI Repository “Time Series” calculations are not widely used

There is a good level of Referential Integrity on the database (so PK, FK and Not Null constraints can be used effectively)


Oracle Database

Oracle BI

Rewrite


Oracle Essbase


Oracle Essbase

Oracle Essbase, like Oracle OLAP, is a world-class cube engine

It was acquired through the Hyperion acquisition and is the main data-source for the Hyperion EPM applications

Whereas Oracle OLAP is part of the actual Oracle Database, Essbase is a separate component

Optimising with Oracle Essbase is generally suitable for:

Customers who already have Essbase (or Hyperion EPM)

Customers with heterogeneous environments (where consolidation into an Oracle database is not an option)

Who are looking to implement Hyperion EPM

Oracle BI

Oracle Other DB Other DB

Essbase


Oracle Essbase

Integration Points with BI EE


Oracle Essbase

Oracle BI EE accesses Essbase cubes via “MDX” queries

As the Essbase cube will already contain metadata on Dimensions, Hierarchies and Measures, modelling can be as easy as drag-and-drop!

As a Data-Source for Oracle BI EE


Oracle Essbase

Demonstration

As a Data-Source for BI EE

Essbase Server

Essbase Studio Server

Essbase Administration Services Server

Essbase Studio Client

Essbase Administration Services Client

Shared Services


Performance Test


Performance Test

Linux Virtual Machine

2.5GB RAM

Oracle Enterprise Linux 5

Software running on Linux VM

Oracle Database 11G (500MB memory)

Oracle BI Enterprise Edition 10.1.3.4

Oracle Essbase 11.1.1.1.0

Host Environment

1 CPU Dual-Core 2.53Mhz

4GB RAM

Windows Vista

Environment


Performance Test

3 sets of identical dashboards:

Mview

OLAP 11g

Essbase

Each dashboard consists of 4 pages:

1 report

2 reports

4 reports

8 reports

The sum of “total database time” from the resulting physical SQL/MDX queries was used for scoring

BI Server caching was disabled

Details


Performance Test Results

Dashboard Reports


Performance Test Results

Compared to Oracle White Paper

OTN White Paper


MV vs Cube Initial Build Times

0

5

10

15

20

25

30

35

Mviews OLAP 11g Essbase

OTN White PaperOur Performance Test


Summary


Summary

Oracle OLAP / Essbase cubes can dramatically improve the performance and scalability of a BI implementation, whilst reducing complexity

Options are available for both “Oracle-only” and heterogeneous environments

Build times and performance in both cube engines are comparable

Any BI/DW developer can build and deploy OLAP and Essbase cubes

BI EE 11g......the “planned” future is bright!


Further Information

Oracle Technology Network:

Oracle OLAP

http://www.oracle.com/technology/products/bi/olap/index.html

Oracle Essbase

http://www.oracle.com/technology/products/bi/essbase/index.html

http://www.oracle.com/technology/products/bi/olap/index.html

http://www.oracle.com/technology/products/bi/essbase/index.html


Peak Indicators Training

BI EE “Advanced” Optimisation training courses will be available from 1st

March 2009

For more information please email : [email protected]

BI EE “Advanced” Optimisation

mailto:[email protected]

© Peak Indicators Limited

Helping Your Business Intelligence Journey

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