Load, Unload, or Stop Loading a Composition
The Load and Unload Composition toggle icon on the Composition Editor toolbar is used to stage complex test compositions prior to clicking Play. Using Load Composition can help identify any problems with the staged components of a given test. This pre-staging of compositions is particularly useful in cloud environments such as Amazon EC2.
Stopping the load process once begun is useful because if there are multiple servers involved it can sometimes take a significant length of time to complete the loading process. Stop the load if you change your mind, or if there are a handful of servers that are taking a long time to load (because of network, configuration, or other issues) and you wish to not wait any further and play the Composition with the number of servers that have been loaded so far.
To stop the Load, click the Load/Unload icon a second time whenever it displays the red stop icon superimposed over the load icon (as shown below).
Clicking Stop the Load can, in some cases, still result in a usable composition. For example if 100 servers are configured for a composition, but Stop the Load is clicked when only 92 have been loaded, the result will be a loaded composition that can play with 92 servers using a partial load.
It is possible to proceed with a partial load, for example, when there are one or more servers having trouble. If a partial load is undesired, click Unload.
If Stop the Load is clicked early enough in the load process, before any servers at all have been successfully loaded, then there won't be a loaded composition to play.