15.00 - MaxJoinTables - Teradata Database

Teradata Database Utilities

Product
Teradata Database
Release Number
15.00
Content Type
Configuration
Publication ID
B035-1102-015K
Language
English (United States)
Last Update
2018-09-25

MaxJoinTables

Purpose  

Influences the maximum number of tables that can be joined per query block.

Field Group

Performance

Valid Values

0, and 64 through 128

Zero means MaxJoinTables will use the system default upper limit of 128.

Default

0

Changes Take Effect

After the DBS Control Record has been written.

Usage Notes  

MaxJoinTables sets a system-wide upper bound on the MaxJoinTables cost parameter used during optimization. The value 0 is mapped internally to 128.

The actual maximum number of join tables in a query block is determined by both this field, and by the MaxJoinTables configuration setting in the Optimizer cost profile.

If the RevertJoinPlanning DBS Control field is set to TRUE, or if the RevertJoinPlanning configuration setting for the cost profile is set to TRUE, the maximum join tables is 64, regardless of the MaxJoinTables setting.

Related Topics

 

For more information on…

See…

RevertJoinPlanning

“RevertJoinPlanning” on page 426.

join planning, optimization, and cost profiles,

SQL Request and Transaction Processing.

database limits

SQL Fundamentals.