Memory for In-Memory Hash Joins | Analytics Database 17.20 | Teradata Vantage - Additional Memory for In-Memory Hash Joins - Analytics Database - Teradata Vantage

Teradata Vantageā„¢ - Analytics Database Release Summary - 17.20 What's New

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2024-10-04
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lifecycle
latest
Product Category
Teradata Vantage

This feature provides additional memory for in-memory hash joins. It is automatically in effect for new customers who enable the in-memory feature. Existing customers that are going to upgrade to release 17.20 must contact Teradata customer support to enable this feature manually.

This feature may change the plan from In-Memory Hash Join (IMHJ) fan-out (FO) to In-Memory Dynamic Hash Join (IMDHJ). This feature may also reduce the number of fan-outs of an IMHJ because of large FO size.

Benefits

  • More applicability for IMHJ. For example, more queries pick up In-Mem hash joins over other join types.
  • More applicability for IMDHJ algorithms, which is the most efficient variation of IMHJ algorithms.
  • Improvement in I/O for applicable queries.
  • Improvement in CPU for applicable queries.
  • Higher throughput (queries-per-hour) for concurrent execution.

Considerations

  • This feature is disabled by default.