SQL Performance & Dynamic parameters

Hello guys

I am working on a module that uses Oracle Public APIs for EBS R12. One of the interesting factors I have noticed while executing queries from the custom forms those refer seeded table was the performance gains immediately after the first execution.

For example, I am searching for AR tables for open invoices for customer XYZ. The first time when I query (We've 11 years old data) it take almost a 40 seconds to fetch the results (a consolidation of open invoices). However, when I execute the query for another customer 'ABC' the result is almost instant. I know bit about cache mechanism, however the knowledge is not adequate enough to satisfy my curiosity. I believe the performance gains are mainly due to the tables/views those referred in the query are already loaded in to the memory, thus querying the objects gain