Home > Ask the Data management / BI Experts > DBMS and data warehousing Questions & Answers > VSAM to DB2 migration project design
Ask The Data Management Expert: Questions & Answers
EMAIL THIS

VSAM to DB2 migration project design

Craig Mullins, Years 2005-2006 EXPERT RESPONSE FROM: Craig Mullins, Years 2005-2006

Pose a Question
Other Data Management Categories
Meet all Data Management Experts
Become an Expert for this site


Enterprise IT tips and expert advice
Digg This!    StumbleUpon Toolbar StumbleUpon    Bookmark with Delicious Del.icio.us    Add to Google


>
QUESTION POSED ON: 06 February 2007
I am currently working on a VSAM to DB2 migration project. As part of our data model, we have arrived at about 200 DB2 target tables from around 50 files. There is at least one COBOL program which needs to access 40+ DB2 tables to do core daily processing.

Given the number of tables to be accessed (40+), the idea we currently have is to use the DB2 V8 feature of MQTs. So, we are planning to create 4 to 5 MQTs, which will hold data pertaining to the 40+ DB2 tables we have.

The point is, the MQTs will not really be used as Summary tables, but rather to just enable one SELECT operation to retrieve lots of columns. In terms of volume, we have close to 2.5MM rows.

How good a design is the above in terms of performance?


>
Well, in terms of query performance it sounds like a good decision. With an MQT, the data is gathered and stored physically so that the next time you access the data you do not have to go through the machinations of joining, etc. So the same query going against an MQT query can run faster than going against the base tables.

But a lot depends on how static the data is. Are you aware that an MQT is not updated immediately when the underlying base tables are updated? So if you have an MQT joining EMPLOYEE to DEPARTMENT, and then you delete an employee row, that employee will still show up in the MQT until you run a refresh of the data. If the data in the underlying tables is quite volatile, then MQTs are probably not the appropriate choice for you.

My first question would be this: did you test to make sure that performance will be a problem without the MQTs? It may be, but then again, it might not be. With proper database design and appropriate indexing you might be OK without the MQT. This is not a question that can be adequately addressed in an online forum. I suggest that you consider hiring a skilled DB2 consultant for a couple of days to present your design to him/her, and solicit feedback and suggestions. If you are looking for help on a good consultant, YL&A has some good DB2 talent.


Digg This!    StumbleUpon Toolbar StumbleUpon    Bookmark with Delicious Del.icio.us    Add to Google



RELATED CONTENT
DBMS and data warehousing
Definition of primary, super, foreign and candidate key in the DBMS
What is the difference between a logical and physical warehouse design?
What are some emerging data warehouse and DBMS trends?
How to get data/database independence with a three-tier architecture
How to select an MPP database: DB2 vs. Teradata
What comes first — the data mart or the data warehouse?
What are the top database management systems (DBMS)?
What is the role of DBMS in RDBMS?
Is an Inmon-modeled BI system, like Madison, the future of data warehousing?
What are the benefits and disadvantages of a RDBMS?

Data modeling tools and techniques
Understanding five major enterprise information management benefits
Data modeling concepts: How settings can increase application success
Advantages and disadvantages of XML shredding
How to shred XML with the DB2 XMLTABLE function
Shredding XML docs into relational tables with annotated XML schemas
Examples of single and bulk XML shredding of XML documents
Improving ODBC application performance and coding
How to capture metadata information, ETL rules with CA Erwin Data Modeler
Data Warehouse Platforms Product Directory
Data models serve as blueprint for business intelligence, master data management projects

IBM DB2 management
How to select an MPP database: DB2 vs. Teradata
What are the top database management systems (DBMS)?
Are there benefits to using both Teradata and a DB2 database?
Tips for evaluating top database management systems and choosing a small DBMS
Exec explains IBM's Information On Demand (IOD) initiative
IBM DB2 9 Fundamentals certification (Exam 730): Sample questions about tables, Part 7
IBM DB2 9 Fundamentals certification (Exam 730): Sample questions about tables, Part 6
IBM DB2 9 Fundamentals certification (Exam 730): Sample questions about tables, Part 5
DB2 basics
IBM DB2 basics

RELATED GLOSSARY TERMS
Terms from Whatis.com − the technology online dictionary
data modeling  (SearchDataManagement.com)
predictive modeling  (SearchDataManagement.com)

RELATED RESOURCES
2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems
Search Bitpipe.com for the latest white papers and business webcasts
Whatis.com, the online computer dictionary



Search and Browse the Expert Answer Center
Search and browse more than 25,000 question and answer pairs from more than 250 TechTarget industry experts.
Browse our Expert Advice

About Us  |  Contact Us  |  For Advertisers  |  For Business Partners  |  Site Index  |  RSS
SEARCH 
TechTarget provides technology professionals with the information they need to perform their jobs - from developing strategy, to making cost-effective purchase decisions and managing their organizations' technology projects - with its network of technology-specific websites, events and online magazines.

TechTarget Corporate Web Site  |  Media Kits  |  Site Map




All Rights Reserved, Copyright 2005 - 2009, TechTarget | Read our Privacy Policy
  TechTarget - The IT Media ROI Experts