In some implementations, there is provided a method that includes receiving a query request including a top k query operator for query plan generation, optimization, and execution, wherein k defines a threshold limit of query results for the top k query operator; inserting into a query plan a check operator associated with the top k query operator; in response to executing the query plan, checking, by the check operator, whether an early exit occurs due to the top k query operator reaching the threshold limit; in response to the early exit occurring due to the top k query operator reaching the threshold limit, stopping processing, by the check operator, including opening of another fragment of a database table; and in response to the early exit not occurring, allowing, by the check operator, the opening of the other fragment of the database table.