OBIEE - Stitch Join (Intern Join Operations)

About

Stitch Join are join operations performed by OBIEE with its intern engine: the Oracle BI Server’s join engine.

The BI Server creates TMP (temporary) files in the ORACLEBIDATA/tmp directory

The Oracle BI Server’s join engine is seamlessly invoked when necessary, depending on the following:

• physical location of tables,
• SQL functionality supported by the source database(s),
• and analytical complexity of the original logical query.

Join plans are constructed to maximize collective function shipping down to the source databases. Two types of internal join strategies are currently supported:

• (1) sort-merge,
• (2) nested loop, parameterized query joins.

Articles Related

Implication of the driving Table

The implication of a driving table in a nested loop join : Nested Loop - Driving Table.

The driving table is generally very small and the other table large in the join.

Documentation / Reference

• BI Server Query Parameters – Driving Tables and Parameterized Sub-Queries