Joins that do not require record caches

There are two join cases that do not require record caches:

Switch joins do not do record comparisons and, hence, do not require record caches for their data sources. You can use any type of record server component (record adapter, record cache, record assembler, Perl manipulator, and so on) as a source for a switch join.
For a left join, for which all of the right sources are record caches, the left source does not require a record cache. This special case is useful for optimizing a left join with a large, unsorted data source.