Systems and methods are described for determining a record generation estimate related to a particular processing task. The system obtains a sample set of data that includes multiple records. The system applies a processing task, such as a transform or regular expression rule to the sample set of data and determines how many records are generated by the processing task. Based on the number of records generated, the system determines a record generation estimate. The system can use the record generation estimate to allocate compute resources or determine a query execution time for at least a portion of the query based on the record generation estimate.