Teradata Pro

Teradata Workload Management – The Priority Scheduler

[su_heading]

Overview

[/su_heading] In our previous article we defined the term workload and described how the Teradata workload management classifies requests (queries) into workloads. We mentioned shortly, that resource allocation (CPU seconds and IOs) is one of the main reasons why we are grouping requests.

If you are new to workload management I would highly recommend that you read our first…

Teradata Workload Management – The Basics

Everyone who has some experience with Teradata tuning will have heard the term “workload”. This article will deal with the definition of this term and explain in detail what it is and why it’s helpful to map each request (query or load operation) to a workload.

What is Teradata Workload?

Workload is a group of requests with common characteristics. The grouping of requests into workloads has some…

Express requests are send to the AMP by the Parsing Engine each time it needs access to data dictionary information from the DBC database which is not cached in memory.

While user requests (such as SQL queries you are running) have to pass several stages in the Parsing Engine (resolving, syntax checking, permission checking, optimization), express requests are bypassing all this steps.

Instructio…

Monitoring The Flow Control State on Teradata

The DBC.ResUsageSAWT table is our main tool to analyze the workload when it comes to flow control state. Before going deeper into details, we will talk briefly about the main characteristics of table DBC.ResUsageSAWT:

Many of the measures of this table represent the status at the end of a 10 minute snapshot interval. As the database administrator may have changed the interval,  it could be…

Improve your Teradata Load Performance

Teradata allows only a limited number of bulk loads to be executed simultaneously as they consume a lot of resources.  The concrete limit depends on your Teradata system. It will be somewhere in the lower 2-digit area.

Whenever the utility limit is reached, additional requests will end up in a workload queue. On a heavily loaded system, this will lead to a unstable load behavior: Run times for…

What is Teradata Concurrency Control?

  Concurrency control  prevents that different sessions are updating, deleting or inserting rows at the same time. Two mechanisms are used to for concurrency control: Locking and Transactions.

Teradata Transactions

Transactions define logical units which are encapsulating one or several statements. All statements of the same transaction have to succeed,…