17.10 - SkewAllowance - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - Database Utilities

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Configuration
Publication ID
B035-1102-171K
Language
English (United States)

Makes allowance for data skew in the build relation. SkewAllowance specifies a percentage factor used by the Optimizer in choosing the size of each hash join partition.

SkewAllowance reduces the memory size for the hash join specified by HTMemAlloc. This allows the Optimizer to take into account a potential skew of the data that could make the hash join run slower than a merge join.

Field Group

Performance

Valid Range

20 though 80%

Default

75%

This is the recommended setting.

Changes Take Effect

After the DBS Control Record has been written.

Related Information

See HTMemAlloc.