17.00 - Method for Detecting Skew - Teradata Workload Management

Teradata Vantageā„¢ - Workload Management User Guide

prodname
Advanced SQL Engine
Teradata Workload Management
vrm_release
17.00
created_date
June 2020
category
Administration
User Guide
featnum
B035-1197-170K

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.