Developer can try to get big data like more than 160000 lines in xlsx report 
Using controllers Get data (To get Data Use Query) and prepare or arrange the data using 

call controllers from python or JS 

import io 
import xlsxwriter

 finally close the workbook and 
change the arranged data has like bytes 

output = io.BytesIO() 
workbook = xlsxwriter.Workbook(output, {'in_memory': True}) 
worksheet = workbook.add_worksheet() 

workbook.close() 
output.seek(0) 
return output.getvalue()

and In controllers return make_response as

@http.route('/big_data_xlsx_report', type='http', auth='user', methods=['POST'], csrf=False) 
def get_report_xlsx(self, model, output_format, report_data, report_name, **kw): 
    uid = request.session.uid 
    report_obj = request.env[model].with_user(uid) 
    load_data = json.loads(report_data) 
    try: 
        if output_format == 'xlsx': 
            cell_data = report_obj.get_report_data(load_data) 
            report_bytes = report_obj.prepare_report(call_data) 
            response = request.make_response( 
                report_bytes, 
                headers=[ 
                    ('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'), 
                    ('Content-Disposition', content_disposition(report_name + '.xlsx')) 
                ] 
            ) 
            response.set_cookie('fileToken', 'dummy-because-api-expects-one') 
            return response 
    except Exception as e: 
        se = _serialize_exception(e) 
        error = { 
            'code': 200, 
            'message': 'Odoo Server Error', 
            'data': se 
        } 
        return request.make_response(html_escape(json.dumps(error)))

with fraction of seconds user can get big data in report

For high volume reporting tasks you should use Aeroo Reports and it's support for deferred tasks. Original reports are usable only with low volume data. Even if normally report would time out, if report is run as a deferred process, it would create background task. Once completed it would store the report along the task.

More over the deferred processing module + Aeroo Reports would work transparently, you can set a threshold for each report, to initiate deferred task, if not exceeded it would run Aeroo report as usual - without creating deferred task.

You can integrate other long running processes to be used as deferred tasks, like mass recalculations etc.

Ok there is one "problem" - you need to redevelop "original" reports into Aeroo.

BR Kaspar

Hi Akhmad,

We upgraded our server and created a swap space of 8GB which allowed us to run a 700+ page long General Ledger Report.

The suggestion of Aeroo reports is good and we were thinking of converting the GL report to HTML (and not PDF). It seems it is convert to PDF which was causing problems and not fetching the data.

HTH Rohit

Hi Rohit did you mean creating swap space of 8GB on the OS/Linux? what is the size of PDF generated in your case?

Thanks