Each time the job is executed, a new ExecutionHistoryItem object is created to represent that instance of the job. These history records are periodically purged, based on the job's HistoryRetentionOptions and HistoryRetentionLimit. 

GetExecutionHistory gets all ExecutionHistoryItems for the job. The data is refreshed from the server if necessary to get the latest information. 

Because retrieving the data from the database and transmitting it to the client can be time-consuming, you can limit the number of records returned by using the maxRecords parameter. The returned collection is always sorted in descending order by the instance ID, so if you limit the number of records to n, you will receive the most recent n instances. 

To get the most recent instance, for example, set maxRecords to 1. 

When the method returns foundRecords is set to the number of instances that actually exist for the job. User-interface applications therefore can first call the method with some reasonable value for maxRecords and then, if foundRecords exceeds this number, prompt the user before calling the method again to retrieve all records (this is the approach used by the adTempus Console). 

Each call only retrieves records that have been created since the last time the method was called, so calling the method frequently does not result in the same data being repeatedly sent from the server.