Skew Exception Criteria | Teradata Vantage - Skew Exception Criteria - Teradata Workload Management - Database Engine 20

Workload Management User Guide - 20.00

Deployment
VantageCloud
VantageCore
Edition
VMware
Enterprise
IntelliFlex
Product
Database Engine 20
Teradata Workload Management
Release Number
20.00
Published
June 2025
ft:locale
en-US
ft:lastEdition
2025-11-20
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icm1467243640567
Product Category
Teradata Vantage

A skewed request can severely impact the parallel efficiency of the system, eliminating the benefit of multiple AMPs. If the system is processing one skewed request step, all the AMPs with less processing to do must wait until the single skewed AMP with more processing to do completes. Only the skewed AMP runs at capacity while the other AMPs sit idle. In a mixed workload, the skewed AMP cannot respond as quickly as the other AMPs because it is clogged with skewed processing. All requests in the system can slow down when there is a skew.