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29 May 2012

There’s a comment on an earlier blog posting of mine from 2009 titled Controlling the Flow of Work in Teradata.  The comment poses a question that is more reasonably answered by making second posting on flow control. 

10 May 2012

A common problem with web applications is that sorting results are inconsistent between the front-end and back-end because the browser and server collation tables differ. These differences force a developer to do all sorting either in the front-end or back-end, which is not very good solution. An application should not have to pay a penalty of a network call just to sort and the server should not get pinged for every sort either. A developer should have the ability to select the best solution for a given problem.

03 May 2012

This is the final installment of a four part series on modularizing the Backbone.js Todos application using Require.js. It examines porting the application to the Pokki platform. 

29 Apr 2012

A quintillion is 10 raised to the power of 18 (that is, 1 followed by 18 zeros).  9.2 quintillion (or more precisely, 9,223,372,036,854,775,807) is the new limit in Teradata Database 14.0 for the number of combined partitions.  Note that this is the same as the maximum BIGINT value (which is a signed 8-byte integer).  While tables that are defined with 65535 or less combined partitions still use 2-byte partitioning, if the number of defined combined partitions exceeds 65535 for a table, the table is created with 8-byte partitioning.

25 Apr 2012

AMP worker tasks are the dedicated tasks inside each AMP that get the database work done.  As there are a limited number, this important resource is actively monitored by DBAs on busy systems.  TASM system-level events can take care of the monitoring for you, and based on a threshold you have set set, will trigger changes in workload management setup to manage the AWT shortage.  How AMP worker task events do their monitoring has changed in Teradata Database 13.10, and this posting describes those changes.

23 Apr 2012

This blog entry provides a brief introduction to underscore.js mixins.

20 Apr 2012

The Teradata Database has support for several data types where there is no equivalent Framework Class Library (FCL) type.  For these types, the Teradata Data Provider has a corresonding Provider Specific Type.  All the provider types support:

06 Apr 2012

One of the more infamous data usage stories over the last week concerned the removal of the iPhone app, “Girls Around Me.”  This app aggregated Foursquare and Facebook data via their respective APIs to generate a map, with pictures, of women in the immediate vicinity that had checked in their locations using Foursquare.  Note that this is not the only app that uses gender specific Foursquare location data, but it was the first to also automatically pull and display the Face

02 Apr 2012

Statistical information is vital for the optimizer when it builds query plans.  But collecting statistics can involve time and resources.  By understanding and combining several different statistics gathering techniques, users of Teradata can find the correct balance between good query plans and the time required to ensure adequate statistical information is always available.

The following statistics collection recommendations are intended for sites that are on any of the Teradata 13.10 software release levels.  Most of these recommendations apply to releases earlier than Teradata 13.10, however some may be specific to Teradata 13.10 only.

21 Mar 2012

With row partitioning (for a PPI or column-partitioned table), the Teradata Database makes sure rows are placed in their appropriate partitions.  When the row partitioning for the table is altered, rows may need to move from one partition to another so they are in their appropriate partitions according to the altered partitioning.  The partitioning expression must be deterministic (always computes the same value for the same value of the partitioning column) to properly place and retrieve the row.

For instance if the table has RANGE_N partitioning, ALTER TABLE will move rows automatically from NO RANGE to newly-added ranges as needed.  Also, if a range is dropped, rows from that partition are moved to the NO RANGE, NO RANGE OR UNKNOWN partition or a newly-added range that covers the dropped range.