object storage past, present, and future douglas k. barry principal barry & associates, inc....

Object Storage Past, Present, and Future

Douglas K. BarryPrincipal

Barry & Associates, Inc.13504 4th Avenue SouthBurnsville, Minnesota 55337 USA

voice: +1-952-892-6113 fax: +1-952-892-5966email: [email protected]: http://www.barryandassociates.com

Barry & Associates, Inc.

Full disclosure

Background• Training and industry practice in relational DBMSs• Got involved in object DBMS technology in 1987

Current Practice• Consultant in the area of selecting object DBMS

and object-relational mapping products• Serve as the Executive Director of the Object

Data Management Group (ODMG)


We will cover ...

Why object storage started the way it did

What is the current state of the industry

What impacts good object storage decisions

What distinguishes current object storage products

What will happen with object storage in the future

What standards will be important

What will characterize the major players in object storage


Why object storage started the way it did

Need for high performance on complex data

Need for multi-user database access to

replace flat file single-user systems

Computer-Aided Design (CAD) drove many of

the requirements


Complex data

often lacks unique, natural identification

often has a significant number of many-to-many relationships

often requires traversing a graph structure in the application(s)


Why not relational DBMSs?

Provided the desired multi-user database access

But performance was terrible on complex data


Why performance was terrible

ServerClient

Objects in theapplication

Tuples stored on disk

Impedancemismatch


Model mapping

ObjectApplication

DBMSServer

ModelMapping

Object programminglanguage uses one datamodel (object model)

Model mapping translatesthe two data models

DBMS server uses anotherdata model (relational model)


C++ entered the scene

Object-oriented languages existed for some time

The most notable language was Smalltalk Others included Lisp (CLOS), Objective-C,

and Eiffel C++, however, captured the market


C++ binding for object DBMSs

ServerClient

Objects in theapplication

Objects stored on disk

No impedancemismatch


C++ binding for object DBMSs

Possible to store any C++ data structure directly with no mapping code

One model for both the application and database

No impedance mismatch Cache management Performance was 100 to 1000 times faster

the relational DBMSs on complex data Less code to write -- lower development costs


Object DBMS cache management

ObjectApplication

DBMSServer

Cache

Object programminglanguage uses an object model

Cache management ispart of the binding with nomodel mapping

DBMS server uses the sameobject model as the objectprogramming language


Object DBMSs use

Aerospace Design Financial Manufacturing Publication Telecommunications Transportation


Object DBMS market size

0

200

400

600

800

1000

1200

1400

1600

1998 1999 2000 2001 2002 2003 2004 2005

$ M

illio

ns

Source: Frost & Sullivan, www.frost.com

Compound Annual Growth Rate (1998-2005): 46.9%


Effect of Y2K on object DBMS market

1998 and 1999 were low-growth years for object DBMS products

A significant portion of new development money went into Y2K fixes during these years

This had a major impact on the object DBMS market since object DBMSs are primarily used for new development


What is the current state of the industry

Relational DBMSs have maintained their market

The relational DBMS market has effectively become the object-relational market

Object DBMSs have exhibited a healthy growth rate

Large disparity between market size for Object DBMSs and Relational market

XML is entering the scene


And Java has entered the scene

Significant use in new development

Created new demands for object storage

options


And XML has entered the scene

XML model is basically an object model And like Java, XML has:

• Significant use in new development

• Created new demands for object storage options


XML

<?xml version="1.0"?><?xml-stylesheet href="catalog.xsl" type="text/xsl"?><!DOCTYPE catalog SYSTEM "catalog.dtd"><catalog> <product description="Cardigan Sweater" product_image="cardigan.jpg"> <catalog_item gender="Men's"> <item_number>QWZ5671</item_number> <price>39.95</price> <size description="Medium"> <color_swatch image="red_cardigan.jpg">Red</color_swatch> <color_swatch image="burgundy_cardigan.jpg">Burgundy </color_swatch> </size> <size description="Large"> <color_swatch image="red_cardigan.jpg">Red</color_swatch> <color_swatch image="burgundy_cardigan.jpg">Burgundy . . .


XML is complex data

some nodes lack unique, natural identification

has a significant number of many-to-many relationships

requires traversing a graph structure in the application(s)

CardiganSweater

description

Men's

Women's

item numberprice

description

Medium

description

Large

description

Small

description

Medium

description

Large

description

Extra Large

Red

Navy

Burgundy

Black

Product CatalogItem

Size ColorSwatch

ProductImage

item numberprice


Java and XML are going to drive object storage

Java appears to be the language of choice for new development

XML will be used more extensively as time goes on

The Java and XML object models will drive the need for efficient object storage – particularly in the middle tier


Three-tier or n-tier architecture

Internet

Middle tier

Bottom tier

XML

XML and Java

Existing data


Object storage growth will be primarily in the middle tier

Internet

Middle tier

Bottom tier

XML

XML and Java

Existing data


Middle-tier object storage options

Object DBMSs (ODBMSs)

Object-relational mapping (OR Mapping)

Relational DBMSs (RDBMSs)

Native XML DBMSs


What impacts good object storage decisions

Need to know your application needs – especially the nature of your data and how you will use the data

Need to study the features of the various products

Need to analyze how the features of products fit or modify your application needs


What distinguishes current object storage products

Object DBMSs (ODBMSs)

Object-relational mapping (OR Mapping)

Relational DBMSs (RDBMSs)


Object DBMSs

ObjectApplication

DBMSServer

Cache

Tight binding with object programming language

Application cache (some also have a server cache)

No model mapping DBMS and application

use same model Highest performance on

complex data Lowest development cost


Object-relational mapping

ObjectApplication

DBMSServer

Cache

ModelMapping

Tight binding with object programming language

Application & server cache

Model mapping DBMS and application

use different models Moderate performance

on complex data Moderate development

cost


Relational DBMSs

ObjectApplication

DBMSServer

ModelMapping

Loose binding with object programming language

No application cache Model mapping DBMS and application

use different models Lowest performance on

complex data Highest development

cost


More on model mapping

Product

Catalog Item

Product Image Size Color Color Swatch

Size

ProductImage

Product

CatalogItem

Size

Color Swatch

Tables Objects

XML


Product classification summary

Product Type Performance on complex data

Development Cost

ODBMSs Highest – there is caching and no model mapping

Lowest – there is only one model

OR Mapping Moderate – cost of model mapping depends on ratio of reads to writes

Moderate – model mapping is separate from application

RDBMSs Lowest – model mapping and no caching

Highest – model mapping is not separate from application


Consider ODBMSs when...

You have a new application that needs high performance on complex data• 10 to 1,000 times faster than relational DBMSs

depending on data complexity• Allows for lower hardware costs to achieve

performance

You have a new application, but the data is not necessary complex• Allows for reduced development costs


Consider OR Mapping when…

You have a new application that uses existing data from one or more existing databases

You have a new application that uses complex data, that has a high read to write ratio• Need to 10 to 100 reads of an object for every

write to meet performance of ODBMSs, or• Plan on running with more powerful hardware to

meet the performance of ODBMSs• Higher development costs than with ODBMSs


Consider RDBMSs when...

You want to add some object characteristics to an existing application/database to improve performance

You want to develop a new application, but your data is not complex• Development cost, however, is higher than with

ODBMSs or OR Mapping products since you will have more code to write

• Nevertheless, you probably have people who are familiar with the RDBMS on staff


Some architectural options

Internet

Middle tier

Bottom tier

XML and Java


Options for new data

Middle tier

Bottom tier

ObjectApplication

DBMSServer

Cache

ObjectApplication

DBMSServer

CacheModel

Mapping

ObjectApplication

DBMSServer

ModelMapping

Object DBMS RDBMS OR Mapping


Options for using existing data directly

Middle tier

Bottom tier

DBMSServer

ObjectApplication

CacheModel

Mapping

RDBMS OR Mapping

ObjectApplication

DBMSServer

ModelMapping


Object DBMS with relational DBMS

Middle tier

Bottom tier

ObjectApplication

DBMSServer

Cache

Object DBMS Object DBMS and RDBMS

ObjectApplication

DBMSServer

ModelMapping

Cache


Object DBMS with object-relational mapping

Middle tier

Bottom tier

ObjectApplication

DBMSServer

Cache

Object DBMS Object DBMS and OR Mapping

ObjectApplication

DBMSServer

Cache CacheModel

Mapping


Middle-tier ODBMS/RDBMS example

The Chicago Stock Exchange uses the Versant ODBMS for its trading system in the middle tier. The trading system stores data at the end of the trading day in Oracle for running existing back-office programs. There is a description of the trading system along with architectural diagrams at www.howstevedidit.com. This URL will re-direct you to a Microsoft site that provides several choices. Follow the Technical Roadmap choice.


What will happen with object storage in the future

RDBMS vendors will universally adopt parts of SQL: 1999 (SQL3) • Will still have impedance mismatch with object

programming languages since the SQL: 1999 object model does not match with Java or C++

Tight object language bindings with caching will become universal• The JDO specification is the most likely candidate

for a standard


What standards will be important

SQL-1999 (www.incits.org) ODMG 3.0 (www.odmg.org) Java Data Objects or JDO

(access1.sun.com/jdo)


More on SQL: 1999

Overriding principle is backward compatibility with SQL-92

As a result of this principle, the SQL: 1999 object model does not match either Java or C++ object models


More on ODMG 3.0

Overriding principle is transparent persistence for object languages

As a result of this principle, the ODMG 3.0 object model matches both the Java and C++ object models


More on Java Data Objects

Overriding principle is to provide transparent persistence to both object and relational DBMSs

As a result of this principle, the JDO object model matches both the C++ and Java object models and provides an automatic mapping to relational DBMSs where needed


What will characterize the major players in object storage

Ease of Java use Performance with Java Ease of XML use Performance with XML Ease of use with J2EE-compliant application

servers, including both container-managed and bean managed-persistence


Free online overview articles

Object databases: www.odbmsfacts.com/articles

Object-relational mapping: www.object-relational.com/articles


Thoughts? Questions?

object storage past, present, and future douglas k. barry principal barry & associates, inc....

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