Troy Coleman

Troy L Coleman

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Recent Posts

  • The Future of Db2 Documentation: More PDFs, More Frequent Updates.
  • IBM Champions: Nomination Period Ends Soon
  • Planning for a Db2 for z/OS Upgrade: Application Testing
  • Contest Introduces Students to the Mainframe
  • Db2 12 Brings Enhanced Data Validation Capabilities to DSN1COPY
  • More on Safe Access Path Changes

    Last week I discussed some parameters that are designed to prevent poor access path changes following a REBIND. As a follow-up, I want to tell you about another new feature introduced in DB2 11 that allows you to not only see current access paths, but determine if a new REBIND will introduce a poor access path change.

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    Posted: June 30, 2015 |

    Avoiding Problematic Access Path Changes

    This message, with the subject “application performance issues,” was recently posted to the DB2 listserv.

    The gist of it is that an application that once took only a few minutes to run now requires more than 70 minutes to process. The application previously used three indexes, but after the rebind it doesn't. So what's the problem?

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    Posted: June 23, 2015 |

    Computers You Can Wear

    While posting about the new z13 IBM Redbook last week, I discussed some of the hottest topics in the technology marketplace. It's a certainty that more and more devices will continue to drive up data storage on z Systems.

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    Posted: June 16, 2015 |

    z13 Designed for Cloud, Analytics and More

    As a follow-on to last week's post about hosted DB2, I'd like to tell you about a new IBM Redbook.

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    Posted: June 09, 2015 |

    Hosted DB2

    Software as a service (SaaS) is a way of delivering applications over the Internet. Rather than hire an in-house staff to install and maintain the software, company developers simply access the tools they need online.

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    Posted: June 02, 2015 |

    DB2 11 Improves Duplicate Removal in SQL Result Set

    When DBAs tune SQL, one of their priorities is to find SQL that invokes sorts, because sorts are expensive.

    The statements that typically cause sorts are SELECT DISTINCT and GROUP BY. Other causes of sorts include the use of MAX/MIN aggregate functions and certain non-correlated subqueries (not transformed). The latest DB2 release, DB2 11, is designed to bring improved query performance to applications that use these types of statements.

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    Posted: May 26, 2015 |

    A Great Time at IDUG NA 2015

    The recent IDUG NA 2015 conference was, in my opinion, the best IDUG event in years. Attendance was way up, and you could feel the energy and excitement during the sessions. Maybe best moment came out of the opening session. When the first-time attendees in the audience were asked to identify themselves, by my count about 30 to 40 hands went up.

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    Posted: May 19, 2015 |

    Using SQL in a UTS Conversion

    Last week I wrote about converting simple table spaces to partition by growth (PBG) Universal Table Spaces (UTS). This week I'll share some SQL that can be used in this conversion process.

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    Posted: May 12, 2015 |

    Revisiting Universal Table Space

    After seeing recent discussions about converting simple or segmented table space to partition-by-growth (PBG) universal table space (UTS) on the DB2 mailing list,. I thought I'd cover this topic. I've previously written about UTS, but it's been awhile. My first UTS post was back in 2007. Then in 2009 I wrote about IBM's migration path to UTS.

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    Posted: May 05, 2015 |

    A Look at DB2 for z/OS OLAP Functions

    I was recently asked how to calculate the moving average for a given metric. To be honest, I've only done minimal work with OLAP functions, so I consulted the SQL Reference guide for help. I need to see examples to get an understanding of how things work; unfortunately, those were lacking in the reference guide.

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    Posted: April 28, 2015 |

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