HASH JOIN RIGHT OUTER
Short Description
A method for joining large data sets. Right Outer joins returned data will include unmatched rows from the table specified after the RIGHT OUTER JOIN clause.
Detailed Description​
As above - used on joining large data sets and can result in table scans occurring.
Non matched and NULL child rows are returned.
The hash table will be built in memory and if insufficient memory is allowed, it will spill to disk in the TEMPORARY tablespaces impacting performance.
Further Reading​
- Oracle Magazine - How to read an execution plan
- Oracle Tuning Guide - Explaining and Displaying Execution Plans
- Oracle Tuning Guide - Comparing Execution Plans Tutorial
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