Why does the report designer display less data?

A report uses a dynamic dataset. When a parameter is input, the preset preview is normal. If the parameter is empty, the data previewed by the designer is obviously incorrect and the data is missing. We requested the remote support from our service engineer. After reading the report design, we thought there was no problem, but the data was wrong. Later, Yan Jie's service engineer asked me to deploy the Report to the project because the designer restricts data. Originally, the plug-in has restrictions on data. To reduce the memory occupied by the designer, only the maximum memory is set in the designer. If there is too much data, part of the data is automatically removed. The designer only provides style design and debugging. After deployment, the report can be displayed. However, it is not possible to store an infinite amount of data, and the JVM also has a memory limit. Therefore, it is recommended to set a simple query report for reports with large data volumes, which can be retrieved by page.

Why does the report designer display less data?