Information About

  • Subscribe to our RSS feed.
  • Twitter
  • StumbleUpon
  • Reddit
  • Facebook
  • Digg

Friday, 6 September 2013

Top Ten Most Pervasive Myths About DB2 for z/OS

Posted on 14:47 by Unknown
Today's blog offers up yet another Top Ten list for DB2 users, perusers, and abusers... This time counting down the most common myths that are perpetrated "out there" regarding DB2 and how it works (or doesn't work)...


1.Use Views to Insulate Programs from Change

              This lie has been told for almost as long as DB2 has been around. I first wrote about this way back in 1991 for Database Programming & Design. Check that article out here if you don't understand why this is a bad idea, in general. 

2.Locking Problems Indicate a Database Problem

              Locking problems are generally caused by bad program design. You should write code to reduce the duration of locks and to COMMIT regularly... and then locking won't be a problem, for the most part.

3.Primary Key is Usually a Good Choice for Clustering

              Actually, the foreign key is likely to be a better choice. When you join PK-->FK there will be one PK to multiple FK. Wouldn't it be best if the FKs were clustered on the same page (or pages)?

4.Just Using the Defaults Should Work Out Well

              Don't rely on defaults. Many of them are outdated or wrong... and even if they aren't it will be better if you review and investigate all options before explicitly specifying the parameter value you want. 

5.Programmers Don’t Need to Know How to Tune SQL

              Programming performance-oriented SQL into your programs from the beginning would go a long way toward improving performance overall... and reducing the length of the application development lifecycle. 

6.Black Boxes Work Well for Performance

              No they don't!!!

7.Using NULLs Can Save Space

              No they can't!!!

8.RUNSTATS Aren’t That Important

              If you don't work with up-to-date RUNSTATS then you are hobbling the DB2 Optimizer and almost assuredly getting sub-optimal access paths for your DB2 SQL. 


9.DB2 is a Hog

              If you don't use it properly, every piece of software can become a resource hog. If you acquire the knowledge on how to work properly with DB2 then it will hum along like a well-oiled machine!

10.It Depends!

              This is the answer that can be used for every DB2 question. But if that answer is not followed up with what "it" depends upon, then it is a useless answer... and whoever gave you that answer is probably just trying to get rid of you instead of helping you with your problems.
Email ThisBlogThis!Share to XShare to Facebook
Posted in COMMIT, DB2, SQL, tips and tricks, views | No comments
Newer Post Older Post Home

0 comments:

Post a Comment

Subscribe to: Post Comments (Atom)

Popular Posts

  • DB2 for z/OS Version 9 Beta Announcement
    On May 2, 2006 IBM announced the beta for the next version of mainframe DB2: namely, DB2 V9.1 for z/OS. You can view the announcement here ....
  • Index on Expressions [DB2 9 for z/OS]
    DB2 9 for z/OS offers, for the first time, the ability to create an index on data that is not technically in the table. At this point, you m...
  • When Not to Index
    Answering a question I got via e-mail on indexing... Every now and then I take the opportunity to blog about a question I get through e-...
  • DB2 Locking, Part 8: LOBs and Locking
    When a row is read or modified in a table containing LOB columns, the application will obtain a normal transaction lock on the base table. T...
  • DBA Rules of Thumb - Part 8 (Being Business Savvy)
    Understand the Business, Not Just the Technology Remember that being technologically adept is just a part of being a good DBA. Although tech...
  • DBA Rules of Thumb - Part 1
    Over the years I have gathered, written, and assimilated multiple collections of general rules of the road that apply to the management disc...
  • Can You Write a Redbook?
    If you've been working with mainframes for any period of time you have almost certainly become familiar with the IBM redbook. These are ...
  • Adding Column Names to an Unload File
    I received an e-mail from a reader asking an interesting question. She wanted to know if any of the DB2 unload utilities are able to include...
  • DB2 Locking, Part 15: Tackling Timeout Troubles
    Many shops battle with locking issues and frequently, the cause of performance issues can be traced back to locking issues, more specificall...
  • UPDATE SCHEMA and CATMAINT [DB2 9 for z/OS]
    Welcome back to my blog as I continue our examination of the new features of DB2 9 for z/OS. Today we will look at the new UPDATE SCHEMA cap...

Categories

  • .NET
  • ACID
  • ALTER
  • analytics
  • articles
  • automation
  • award
  • backup
  • best practices
  • BETWEEN
  • BI
  • Big Data
  • BIND
  • blogging
  • book review
  • bufferpool
  • buffers
  • CASE
  • change management
  • claim
  • Cognos
  • COMMIT
  • compliance
  • compression
  • conference
  • constraints
  • COPY
  • data
  • data breaches
  • data quality
  • data security
  • Data Sharing
  • data types
  • data warehouse
  • database archiving
  • database auditing
  • database design
  • date
  • DB2
  • DB2 10
  • DB2 11
  • DB2 9
  • DB2 Analystics Accelerator
  • DB2 Catalog
  • DB2 conversion
  • DB2 Developer's Guide
  • DB2 X
  • DB2-L
  • DBA
  • DDL
  • developerWorks
  • dirty read
  • DISPLAY
  • DL/1
  • drain
  • DSNZPARM
  • Dynamic SQL
  • eBook
  • education
  • enclave SRB
  • encryption
  • ERP
  • FETCH FIRST
  • Freakonomics
  • functions
  • generosity factor
  • Happy Holidays
  • Happy New Year
  • Hibernate
  • HIPAA
  • history
  • IBM
  • ICF
  • IDUG
  • IFL
  • IMS
  • index
  • Information Agenda
  • Informix
  • InfoSphere
  • infrastructure
  • integrity
  • IOD
  • IOD11
  • IOD2009
  • IOD2011
  • IODGC
  • IRLM
  • ISOLATION
  • Java
  • JDBC
  • load balancing
  • LOBs
  • locking
  • LUW
  • mainframe
  • Malcolm Gladwell
  • manuals
  • memory
  • middleware
  • migration
  • misc
  • monitoring
  • natural key
  • Netezza
  • new blog location
  • NoSQL
  • nulls
  • OLAP
  • optimization
  • Oracle versus DB2
  • packages
  • PCI-DSS
  • performance
  • PIECESIZE
  • poll
  • primary key
  • production data
  • programming
  • Q+A
  • QMF
  • REBIND
  • recovery
  • RedBook
  • regulatory compliance
  • reliability
  • REORG
  • research
  • RI
  • RTO
  • salaries
  • SAP
  • scalability
  • security
  • smarter planet
  • SoftwareOnZ
  • sort
  • SOX
  • specialty processors
  • SPUFI
  • SQL
  • Stage 1
  • Stage 2
  • standards
  • Steelers
  • storage
  • stored procedures
  • stream computing
  • surrogate key
  • SYSADM
  • Sysadmin
  • table expressions
  • table space
  • TechDoc
  • tips and tricks
  • Top Ten
  • trace
  • training
  • triggers
  • Twitter
  • UDFs
  • UNION
  • unstructured data
  • user groups
  • utilities
  • V1
  • V10
  • V2
  • V3
  • V4
  • V5
  • V6
  • V7
  • V8
  • V9
  • variables
  • views
  • VOLATILE
  • Web 2.0
  • webinar
  • Wordle
  • XML
  • z/OS
  • zAAP
  • zIIP

Blog Archive

  • ►  2014 (2)
    • ►  January (2)
  • ▼  2013 (50)
    • ►  December (6)
    • ►  November (6)
    • ►  October (5)
    • ▼  September (5)
      • Using the DISPLAY Command, Part 2
      • Using the DISPLAY Command, Part 1
      • Answering a Question: Dealing with Different Data ...
      • Top Ten Most Pervasive Myths About DB2 for z/OS
      • Top Ten Common SQL Mistakes (with DB2 for z/OS)
    • ►  August (3)
    • ►  July (7)
    • ►  June (4)
    • ►  May (4)
    • ►  April (5)
    • ►  March (1)
    • ►  February (2)
    • ►  January (2)
  • ►  2012 (17)
    • ►  December (1)
    • ►  November (2)
    • ►  October (3)
    • ►  August (2)
    • ►  July (1)
    • ►  May (1)
    • ►  April (1)
    • ►  March (2)
    • ►  February (2)
    • ►  January (2)
  • ►  2011 (27)
    • ►  December (1)
    • ►  November (1)
    • ►  October (6)
    • ►  September (2)
    • ►  August (3)
    • ►  July (2)
    • ►  June (3)
    • ►  May (2)
    • ►  April (3)
    • ►  March (1)
    • ►  February (3)
  • ►  2010 (29)
    • ►  December (1)
    • ►  October (6)
    • ►  September (1)
    • ►  August (2)
    • ►  July (2)
    • ►  June (1)
    • ►  May (3)
    • ►  April (3)
    • ►  March (3)
    • ►  February (4)
    • ►  January (3)
  • ►  2009 (43)
    • ►  December (5)
    • ►  November (4)
    • ►  October (6)
    • ►  September (2)
    • ►  August (1)
    • ►  July (3)
    • ►  June (2)
    • ►  May (3)
    • ►  April (2)
    • ►  March (4)
    • ►  February (5)
    • ►  January (6)
  • ►  2008 (44)
    • ►  December (1)
    • ►  November (4)
    • ►  October (4)
    • ►  September (6)
    • ►  August (1)
    • ►  July (4)
    • ►  June (3)
    • ►  May (5)
    • ►  April (4)
    • ►  March (4)
    • ►  February (2)
    • ►  January (6)
  • ►  2007 (51)
    • ►  December (2)
    • ►  November (3)
    • ►  October (5)
    • ►  September (3)
    • ►  August (6)
    • ►  July (4)
    • ►  June (4)
    • ►  May (5)
    • ►  April (8)
    • ►  March (5)
    • ►  February (4)
    • ►  January (2)
  • ►  2006 (60)
    • ►  November (4)
    • ►  October (8)
    • ►  September (4)
    • ►  August (11)
    • ►  July (7)
    • ►  June (2)
    • ►  May (7)
    • ►  April (3)
    • ►  March (6)
    • ►  February (4)
    • ►  January (4)
  • ►  2005 (11)
    • ►  December (3)
    • ►  November (6)
    • ►  October (2)
Powered by Blogger.

About Me

Unknown
View my complete profile