Caching of Query Results within the Graph Editor

 

To improve the performance of the Graph Editor, several caches are used. On the other hand, the use of a cache causes several problems which will be addressed in this section. In particular, the caches of the Graph Editor are not updated automatically if the corresponding data in the server is updated.

Graphical Palette and Graphical Types:

When a connection to a server is established, the Graph Editor loads the graphical palette and all its graphical types including their properties and other information. If an object has to be shown, the server sends only the name of the graphical type, the information about the properties are taken from the cache. Thus, if you change the graphical palette or a graphical type after the Graph Editor has established the connection, this change will not be visible in the Graph Editor. There is currently no method implemented to update the cache manually.

Graphical Types of Objects:

When an object is loaded from the server also the graphical type for this object is retrieved. The graphical type of the object is updated when you invoke the ``Validate and Update'' operation from the ``Current Connection'' menu.

Lists of super/sub classes, classes/instances, attributes:

The lists in the popup menu or in the tree-like view of an object are produced by evaluating queries. To reduce the communication between client and server, each query will only be evaluated once (when the corresponding popup menu should be shown or when the part of the tree should be shown). The result will be stored in a cache for each object. This cache is emptied when you invoke the ``Validate and Update'' operation from the ``Current Connection'' menu.