Method for Detecting Skew - Advanced SQL Engine - Teradata Workload Management

Teradata Vantageā„¢ - Workload Management User Guide

Product
Advanced SQL Engine
Teradata Workload Management
Release Number
17.10
Published
July 2021
Language
English (United States)
Last Update
2021-07-28
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B035-1197
lifecycle
previous
Product Category
Software
Teradata Vantage

In general, TASM detects skew successfully using just the skew percentage metrics. However, some situations can lead to a false detection of skew. In a multi-step request, one step could be very skewed but also short and not indicative of an overall problem with the request. It is important with skew detection that temporary skew within a request not be interpreted as persistent skew and that temporary skew be ignored.

Tip: Do not set the qualification time too low on skew exceptions. The skew condition should persist long enough to qualify as a problem with the request.