The IBM® Database Add-Ins provide the option of using a cache to improve performance while you are developing databases and applications. However, the cache is effective only while it remains a reasonable size. When the cache size is relatively small, it is faster to access data from the cache than from the database. But when the cache becomes too large, performance degrades.
The maximum effective cache size is 60 MB. A cache that exceeds 60 MB can cause a slow response time. For example, an application can take a long time to load. At times, a cache that is much larger than 60 MB can cause Visual Studio to stop.
The growth rate of the cache is directly related to the size and the number of objects that you are working with. You can slow the growth of the cache size and help maintain optimum performance by reducing the number of objects that are available to prefetch. When you add a data connection, use one or more of the following filtering options:
- Schema filter
- Only a specific schema or a set of schemas with a common partial schema name are available to prefetch.
- Exclude system schemas
- System schemas are not available to prefetch.
Table type filter- Only the specified types of tables are available to prefetch.
- Object filters
- Only the selected object types or the set of objects with specific names are available to prefetch.
If the size of the cache file (userCache.xml) exceeds 60 MB at the time it is loaded into the Document Object Model (DOM), a message is displayed. The message states that the cache size exceeds 60 MB, and suggests how you can reduce the cache size. The message can be displayed during either of the following events:
- You start Visual Studio and expand an existing connection to an IBM database in the Server Explorer.
- You start Visual Studio and create a Windows application or a Web application (or open an existing application) and then open the Data Source Configuration Wizard.
If you do not use the filtering options or use only some of them, you can change the properties of your connection after the message is displayed. Using the filtering options ensures that when you close Visual Studio, only the filtered information is saved to the cache.
See Also
Customizing the IBM Database Add-Ins for Visual Studio | IBM Database Tools, Options | Adding IBM Data Connections | Changing the Properties of IBM Data Connections | Add/Modify Connection
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