Restful API is not exporting large volumne of data to XLS or XML

Hi

I am able to export smaller files to XML and XLS files with out any issue from CURL and RESTFUL.

I have a report with close to 1 million records. After schedule complete in wid format then exporting report to XML using RESTFul and curl

I am using below code

curl -G -s -H "accept:text/xml" -H "X-SAP-PVL:en_US" -H $token "http://localhost:6405biprws/raylight/v1/documents/$docid" >>tmp/file.xml

and I tried in CSV, XLS and PDF

WIReportServer is running and utilizing more than 80% to 90%. one session and one user and only above script is running in that

environment but data is not exported to the report.

Is there any row imitation for RESTful API ?   or CURL /RESTful wont support for larger data files ? or it is running long time? or this is not the correct approach?

Please help me on this.

Thanks

Satya