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Message Posted: Sat, 24 Oct 2009 @ 18:46:55 GMT

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Performance tuning is a little vague and could refer to many different things. In my world I would say this relates to the tasks involved in trying to deliver the most "performant" Teradata system possible to the business. This often involves the understanding, analysis and management of every element of the Teradata system (including ETL and backup strategies, mixed workload management, data modelling, hardware / software management and many many more things) with a view to driving the best possible performance from the system.

Query optimisation is more specific to the performance of individual SQL queries. Often there are many different queries which can be written to satisfy a particular requirement and whilst all the different queries may deliver the same results some queries will be more efficient (in terms of system resource usage and response time) than others. Writing SQL queries is relatively simple, writing efficient and optimised queries is an art form.

Spool space errors are a particular type of error which can occur during query execution. They typically occur because either a user does not have enough spool space allocated to execute a valid query, in which case the Teradata DBA can increase the spool space allocated to that user, or a query has been submitted by a user which requires more spool space to execute than the spool limit the user has been allocated because the query has been written in a less than optimum way (in terms of spool space usage). Again, in my world, we only increase a users spool space allocation if we cannot provide an alternate, less spool intensive query to the user (and if we are feeling particularly happy).

My advise to you would be not to apply for the job.

Hope this helps.

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