This diagnostic alert warns you when a long running task has exceeded a set time limit. For example if it took more than 5 minutes to export a space. 

The following appears in the application log:

WARNING ; JOB ; JOB-1001 ; Long running task exceeded time limit ; System ;  ; com.atlassian.confluence.importexport.actions.ExportSpaceLongRunningTask ; {"...}

This alert is enabled by default in Confluence 6.11 or later. 

To resolve this issue

There's no action required for this alert. However, this information may be helpful when investigating an outage or issue such as a slow performing add-on.

What will happen if I ignore this alert? 

This alert is for information only. There's no direct action required.

Can I change the threshold?

Yes, you can change the threshold of this alert using the following system property:

diagnostics.slow.long.running.task.secs

See Configuring System Properties for more information on setting system properties.