Complete Refresh of Materialized View Uses Nested Loops Instead of Hash Joins when Remote Objects Queried over DBLINK
(Doc ID 2052843.1)
Last updated on FEBRUARY 20, 2019
Applies to:Oracle Database - Enterprise Edition - Version 22.214.171.124 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.
The complete refresh of a materialized view with many rows uses nested loops to refresh instead of hash joins. The select statement itself uses hash joins.
Here is an example of an explain plan for the complete refresh. Notice that the estimated cardinality is 1.
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