This project was done to reveal a memory leak in a widely used component in Delphi called TClientDataset.
The company I work for uses TClientDatasets everywhere. We have written many back end tools to support our data delivery systems. One such tool is a custom Windows service which has a TClientDataset dropped on the Service data module. This service runs 24/7. We started noticing the memory would gradually climb up to a max point then the service would lock up. After restarting the service it would do this again. We obviously thought our code had a bug somewhere so after hours and hours of investigation, we came to the conclusion that we need to test TClientDatasets in a stand alone test harness since everything pointed to this as the culprit.
The project was created with Delphi XE7. It was further tested in Delphi 10.2 Tokyo which still has the bug in it.
Test Params: Record Count=1000. Field count=8. Consecutive test count=1000. Random Edit count=50. Random Delete count=50. LogChanges=FALSE
| Delete 50 random records | Edit 50 random records | Go to first record after test | Results |
|---|---|---|---|
| FALSE | FALSE | FALSE | |
| FALSE | FALSE | TRUE | LEAK |
| FALSE | TRUE | FALSE | |
| FALSE | TRUE | TRUE | LEAK |
| TRUE | FALSE | FALSE | LEAK |
| TRUE | FALSE | TRUE | LEAK |
| TRUE | TRUE | FALSE | LEAK |
| TRUE | TRUE | TRUE | LEAK |
Chris McClenny
Dave Clark