The General tab on the Record Cache editor has a Combine Records setting. With the setting enabled for record caches, equivalent records in data sources are combined.
The setting controls how the cache handles records that have equivalent values for the record index key, and it is turned off by default. Care should be taken if you choose to use it.
Consider performing a left join on the following two data sources, assuming the record index key is the property Id. Both sources have records with redundant keys. For example, Source 1 has three records with Id=A and two records with Id=B. Source 2 has three records with Id=A and two records with Id=B.
Without the Combine Records setting enabled, the results of a left join on these two data sources look like this:
With the Combine Records setting enabled for the record caches, equivalent records in the data sources would be combined, so the new data sources would look like this:
The results of a left join on these two combined data sources would look like this:
