Export to Excel generating a Blank File

Products

• Clarity PPM On Premise

Issue/Introduction

When users attempt to export grid data to an Excel file, the export fails or generates an empty file.

Upon reviewing the application logs, the following frequent error message is observed:

ERROR [date/time] [thread] grid.ExcelTransformer (clarity:[session_id]:npt.gridExcelExport) ([uuid]) Unable to process grid as input was null or not found

This issue is typically observed in multi-node environments utilizing a Load Balancer

Environment

Clarity PPM 16.x

Cause

Clarity utilizes a two-step approach to generate and serve Excel files:

1. Data Preparation: Clarity prepares the requested data and stores it locally in the JVM memory of the specific Clarity application node handling the user's session.

2. File Download: The user's browser triggers a subsequent request to download the prepared file once step 1 is complete.

If the Load Balancer does not enforce sticky sessions—or if the sticky session duration is set too low (e.g., 1 second)—the Load Balancer may route the Step 2 "File Download" request to a completely different application node.

Because the newly assigned node does not have the prepared dataset in its local JVM memory, the application evaluates the dataset as "NULL," throwing the error and returning an empty file.

Resolution

To resolve this issue, the infrastructure team must ensure that requests from a single user session are consistently routed to the same application node.

1. Enable Sticky Sessions: Ensure that session stickiness (session persistence) is actively enabled on the Load Balancer routing traffic to the Clarity nodes.

2. Increase Duration: Configure the sticky session duration so that it is equal to or slightly greater than Clarity's configured "Inactive Session Timeout" setting.

   • Note: If a generic value is required by the infrastructure team, 60 minutes is a recommended baseline duration. A duration of 1 second is effectively the same as having stickiness turned off.