Managing Performance

Since the iWay Hierarchy Manager plugin can be used to handle large sets of data, the plugin was developed to process data quickly and allow data reusability for all user actions. For example, the iWay Hierarchy Manager plugin contains caching mechanisms, a responsive user interface, and provides sequential data serialization.

Caching

Caching prevents the iWay Hierarchy Manager plugin from sending continuous requests to data sources, since all of the necessary data is stored in memory once it is initially retrieved. After you request run-time data for the first time, it is retrieved from the data source, stored in memory, and then passed along for additional processing. When this data is required again, the iWay Hierarchy Manager plugin retrieves it from memory and does not request it directly from the data source.

However, this caching description does not cover the scenario when data is preserved between Eclipse sessions. When the Eclipse instance is closed, all data stored in memory is released and cannot be reused in a future session. As a result, file system caching is another caching level that is provided.

When an Eclipse session is closed, all of the cached data from memory is persisted to the project cache folder. This data is represented as tables and persisted to files in XML format. Once a new Eclipse session is started (and during the first call to a data source), all of the file system cache is read into memory. If any exception occurs, a message is generated in the log. After that, the file system cache is not used until the Eclipse session has ended.

Configuring Access to Additional Memory

In the event when the design data of a hierarchy is very large (for example, 30,000 nodes or more in design time), the iWay Hierarchy Manager plugin may crash with an out of memory error. This may occur because of a variety reasons, specifically:

Too many memory-consuming user interface elements (nodes) are being used.
A very large data source result.
The model is too large (error during model serialization to a file in the workspace).

To increase memory for the processing of large sets of nodes, you can configure your Java Virtual Machine (JVM) to allocate more virtual memory during Eclipse startup.

You must configure the following parameters in the eclipse.ini file (located in the Eclipse folder):

-Xmx. Specifies the maximum size, in bytes, of the memory allocation pool. This value must be greater than 2 MB. Append the letter k or K to indicate kilobytes, m or M to indicate megabytes, and g or G for gigabytes. The default value is 64 MB. The upper limit for this value will be approximately 1500 MB on a 32-bit Windows system. For example:
```
-Xmx83886080
-Xmx81920k
-Xmx80m
```
-Xms. Specifies the initial size, in bytes, of the memory allocation pool. The declaration is the same as for the -Xmx parameter. For example:
```
-vmargs
-Xms40m
-Xmx1024m
```