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31 Oct 2011

Reserving AMP worker  tasks (AWT) for tactical applications is a technique to protect business-critical, short queries, when the platform is experiencing AMP worker task exhaustion.   If you are thinking about reserving AWTs, there are two different settings for which you will be required to provide values.  This posting discusses what these two settings are and how to be smart about setting them.

21 Oct 2011

It's about time to start considering the use of Aggregate Join Indexes (AJI) instead of aggregate summary tables and/or aggregate views.

Teradata 13 contains new cool enhancements on the Teradata Optimizer to improve the utilization of the AJI's as listed below. But I have been using successfully AJI's with great results on V2R6 and Teradata 12 too.

18 Oct 2011

Let's start by understanding what a primary index does.  A primary index (PI) is used to distribute the rows of a table to the AMPs and on each AMP to order the rows by hash value within the combined partitions defined by a PARTITION BY clause (if this clause is not specified, there is just one partition, that is, the entire table).

13 Oct 2011

Recently, I was presented with a situation to move several Terabytes of data from one machine to another. So FastExport/FastLoad really wasn’t feasible. I didn’t have the hard drive space to hold the flat files because they were so big. So then I tried to archive the database, but again, the archive file was too big. So digging a little deeper, I found that you can move a database from one machine to another using a named pipe archive.

11 Oct 2011

If you are using Teradata on one of the 1xxx or 2xxx platforms, be aware that query demotions are automatically built into your workload management scheme.   Because I’ve had a few questions about what these so-called "query milestones" are and how they actually work, I’d like to explain this functionality and discuss its trade-offs. 

10 Oct 2011

I was lucky enough to be able to attend Partners in San Diego last week.  As part of that, I did have an opportunity to speak a time or two and discussed a few performance issues.

I discussed swapping, SegIO Reads, and measuring I/O bandwidth but wasn't able to provide detail or queries, etc. at the time.

They are below.

28 Sep 2011

You know how we at DevX World HQ like to keep up with the times... Well, you can now "like" or "plus-one" articles, blogs and forum posts on DevX. This replaces our old "thumbs-up" mechanism. To show the love, just click the appropriate icon in the toolbar at the top of the content page. 

27 Sep 2011

Teradata 14.0 introduces Teradata Columnar – a new option to organize the data of a user-defined table or join index on disk.

Teradata Columnar offers the ability to partition a table or join index by column.  It introduces column-storage as an alternative choice to row-storage for a column partition and autocompression.  Column partitioning can be used alone in a single-level partitioning definition or with row partitioning in a multilevel partitioning definition.

26 Sep 2011

This blog post provides an explanation of Viewpoint portlet date/time stamp behavior. The rationale for the blog post is that often new customers conclude that their portlets are not working correctly as the time stamp does not match the current time or rewind time. So let's do a quick review on the intent of the portlet time stamp.

16 Sep 2011

At the beginning of our current release, the Viewpoint engineering team decided to split itself into multiple cross-functional, self governing scrum teams. Each team consists of 5-10 members that are able to perform all the functions needed to produce working software: from design to development to test.  The Delta Force scrum team was focused on updating Viewpoint to support new Teradata 14.0 database features.  This article talks about some of our challenges and successes in transitioning to a more agile, scrum oriented team.