When dotConnect for Salesforce executes a SQL query locally (either because some of the queried tables are cached, or because the SQL statement cannot be translated to SOQL), the data for the tables, that are not cached, is cached in a temporary database. This cache exists only for the time of query execution, and is cleared after the query is executed. This temporary database usually stays in RAM, however it might be partially flushed to disk if it becomes too large or there is not enough memory, thus providing optimal memory usage and high performance.