TechNote (Archived)

ColdFusion MX: 'Image Expired' error when using cfchart in a clustered environment

Issue

When using cfchart in a clustered environment, the following error may be encountered:

 Image Expired Please refresh the page to view the image

This problem occurs if the cluster manager does not send the user back to the same server where the chart was originally generated by the cfchart tag. To display charts generated by the cfchart tag, ColdFusion creates a temporary SWF, PNG or JPG file on the server. In a clustered environment where there is no session affinity, a user may end up on a server within the cluster that doesn't have the temporary file holding the image. When this occurs and the image cannot be found, ColdFusion assumes that the image has expired and throws the error message.

Solution

To avoid this situation, you must ensure that the cluster forces each client to remain with the same server for each request in the client's session. You do this by enabling session management. Depending on your clustering software, this is called either session affinity or sticky sessions.