症状

Downloading a large attachment, or when a user goes to the attachments view and clicks Download All, the zip file is created and starts to transfer, but appears to hang and never completes.

atlassian-confluence.log に次のエラーが返される。

com.atlassian.plugin.servlet.DownloadException: ClientAbortException: java.net.SocketException: Connection timed out
at com.atlassian.confluence.servlet.download.ServeAfterTransactionDownload.serveFile(ServeAfterTransactionDownload.java:68)
at com.atlassian.plugin.servlet.AbstractFileServerServlet.doGet(AbstractFileServerServlet.java:30)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
 :
 :
Caused by: java.net.SocketException: Connection timed out
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)

原因

In the Standalone version, the Tomcat's connectionTimeout value is set to 20000 milliseconds (20 seconds). Depending on your connection speed, if you require to have a connection longer than 20 seconds then you need to increase the value. It's a good idea to consider the geographic location of your users to gauge the suitable length of time.

ソリューション

Increase the connectionTimeout. See Tomcat's relevant documentation.