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
  • Minimizing the Processing Cost of DB2 Traces

    In a recent blog post, Denis Tronin discussed DB2 for z/OS performance monitoring.
    Denis provides a nice introduction to this topic by examining the different types of trace information. To me, the single most important take-away comes toward the end of the article, when he says: “It is important to understand that traces bring an overhead to your DB2 subsystem, so they should be used wisely.”

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    Posted: April 21, 2015 |

    Fun with SQL

    In writing about the upcoming IDUG DB2 tech conference last week, I noted that the event includes expanded content for developers. This is no isolated occurrence. The IDUG organization has been expanding its focus to include greater education and support for developers (in addition to its traditional audience of DB2 systems programmers and database administrators). With this in mind, I want to mention the "online SQL challenge" that's going on throughout April.

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    Posted: April 14, 2015 |

    A Look at the Upcoming IDUG NA Conference

    The IDUG DB2 North American Tech Conference is May 4-8 in Philadelphia. This year's conference has been expanded by a day to more conveniently spread out the technical education and labs.

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    Posted: April 07, 2015 |

    DB2 Analytics Accelerator for z/OS Resources

    I’ve written extensively about the DB2 Analytics Accelerator. My most recent post, from January, covered IBM's future plans for the product.

    Because the accelerator is becoming a critical tool for DB2 professionals, I wanted to share a couple of resources I’ve recently come across. The first is the IBM Support Portal for DB2 Analytics Accelerator for z/OS. It contains dozens of links to IBM documentation about the accelerator (installation, configuration, maintenance, education, etc.) and business analytics in general.

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    Posted: March 31, 2015 |

    Authorization Checking During Auto Rebind

    Last week I discussed the factors that cause a package to be marked invalid and go through AUTOREBIND. My recommendation was to always REBIND the package manually once the changes have been implemented.

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    Posted: March 24, 2015 |

    Changes that Invalidate Packages

    Certain DB2 changes can cause your application package to be marked invalid. When this occurs, the VALID column of SYSIBM.SYSPACKAGES will contain a value of other than “Y.” Then the next time the package is executed, automatic rebind will occur. If the rebind is unsuccessful, the package remains invalid and the OPERATIVE column is changed to “N.” At this point when the package is executed, an SQLCODE -904 will be returned with a reason code of 00E30305.

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    Posted: March 17, 2015 |

    BIF_COMPATIBILITY Eases Data-Conversion Process

    Software vendors that develop products for the IBM z/OS mainframe know that when new DB2 features are introduced, the old features must still be able to function so that applications running on z/OS aren't affected. Over the past few releases, controlling these changes and their impact on applications has made DB2 migrations much more difficult. Some customers have delayed migrations for years, while others that have migrated needed a year or more to implement the necessary changes and conduct application testing.

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    Posted: March 10, 2015 |

    Time Travel Views Not Supported in DB2 11?

    In 2012 I wrote about new DB2 10 support for temporal tables. Just recently, while reading the DB2 11 for z/OS Application Programming and SQL Guide, I came across this disturbing paragraph found on Page 4 in Chapter 1, under the sub-topic, “Views, materialized query tables, and SQL table functions with period specifications”:

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    Posted: March 03, 2015 |

    Avoiding Indirect References in DB2 11

    When designing the physical structure “table space” used to store table data, DBAs must understand the types of processing that will occur against the table. Will the table have lots of inserts, updates or deletes, or is it mainly read-only? Will the table rows be variable length due to either VARCHAR columns or data compression? Answering these questions helps DBAs choose the appropriate table space storage options during the creation.

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    Posted: February 24, 2015 |

    How to Control Statistics Feedback

    DB2 11 introduced a feature to help identify missing or conflicting statistics that can help the optimizer choose a more efficient access path. I wrote about this feature here, however, I've since learned that two DB2 subsystem parameters can be used to reduce the amount of information collected and control how frequently information is written to memory.

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    Posted: February 17, 2015 |

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