Altair® Panopticon


File Upload Size Limits Settings in Tomcat and Panopticon

Starting with version 2020.0 and the introduction of web authoring, any connection to a file data source involves uploading the file first to the server then loading its data into Panopticon. The upload happens as part of using the data connector for the file.

Setting the limit of the file upload sizes are done in the following properties:

q  maxSwallowSize

This setting is part of the overall Tomcat configuration, particularly for the HTTP connector, and is found in the <tomcat>/conf/server.xml file.

maxSwallowSize controls how much data Tomcat will accept for upload before it is cancelled or terminated. If the file size is larger than the file.upload.size.max.bytes, and the limit of maxSwallowSize is hit, then Panopticon will never get a chance to send a proper error message about the file being too large. The upload will simply be terminated with a message about an unknown error. It is therefore recommended to set the maxSwallowSize value high enough to the file size that Panopticon users are expected to load.

Any minus value (e.g., -1), means unlimited. Setting a minus value for maxSwallowSizecreates a risk of getting the Tomcat connection saturated by a very large file upload or being stuck in an infinite file upload. A reasonable setting would be something between one to two times of the Panopticon file.upload.size.max.bytes  property value.


<Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" maxSwallowSize="100000000"/>

q  file.upload.size.max.bytes

This property is part of the Panopticon specific settings found in the  file in the PanopticonAppdata folder (i.e., c:\vizserverdata).

This size limit property (in bytes) controls how large are the files Panopticon will accept to connect to for loading data.

If the file exceeds the size limit, there will be an informative error message that indicates the current size limit. The size limit check can only take place on the condition that the file has already been successfully uploaded to the server. The upload success depends on the limit set in maxSwallowSize.