Brief summary of the bug. What is it ? Where is it ?

Attempting to export data to CSV from an Optimize report fails when there are more than about a couple of hundred rows in the report. Usually the error returned is “Internal Server Error”, though we have also sometimes seen “Elastic Search Error” and sometimes a blank red error dialog.

Simply running the report (rather than selecting download CSV) also fails with an Internal Server Error message if the page size of the report is set to 500 or 1,000 (it works successfully with a page size of 200).

Note that the issue occurs even for an extremely simple report with only a single column, as in the following reproduction steps.

Steps to reproduce the issue:

1) Log in to Optimize, select the Optimize menu option → Create New → New Report

2) In the Select Process box choose any process that has a lot of instances

3) Select the Blank Report template and click Create Report

4) Give the report a name

5) Under the Report Setup option select “Raw Data”

6) Select the Configuration Options dropdown (the cog), click the Disable All button and uncheck the “Display data from new variables” option

7) Select a single column to include in the report - eg Process Instance Id

8) Click Save

9) Click Download CSV. After a few seconds a red dialog box is shown saying “An Internal Server Error occurred.”.

10) Dismiss the error dialog and select Rows per page → 500 - the system reports “Error loading data An Internal Server Error occurred”.