Amount of memory

The Java process requires more memory than that normally needed for a Blueworx Voice Response environment running only state table applications. When running a Java application, for a system of 120 lines, the Java virtual machine typically needs about 12 to 32 MB, although the exact amount depends on the specific application. For a VoiceXML application using 30 lines, 256 MB of memory would typically be needed, but the following factors can have a significant impact on this requirement, and on performance in general:

• The amount of memory that is allocated to caching VoiceXML pages (cache can be used to avoid having to continuously download pages from a web server). The impact of caching is reduced when running VoiceXML 2.1 applications.
• The efficiency of VoiceXML documents. With VoiceXML documents, there is some impact from tag statements being parsed each time, regardless of whether they are executed. Even though parsing is optimized through the use of cache, it is more efficient to put the tags that are not normally required (for example, those used in error handling) into a separate document that can be called only when needed.
• The number of prerecorded audio files used. A VoiceXML document checks the cache for expiry of audio files, so the more files there are, the longer this takes; for this reason, a document should load into cache only those audio files that it uses.
• The use of ECMA scripts as an extension to VoiceXML. Although this can have a significant impact, the effect can be reduced by using external scripts; these are optimized by the browser, reducing both memory and processor requirements.
• The size of grammar files. These should be kept as small as possible.