XML Optimization for the Highest Performance
Improve XML performance in this post on improved optimization practices.
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XML optimization involves the use of a set of techniques that are used to audit the design of metadata from an XML stream. The goal of optimization is to help the producers of XML minimize the side effects of using the language. The most common shortcomings in XML result from the unmanageable overhead size and the lockdown of different versions of XML. An increase in the number of results is likely to demand a higher network bandwidth in order to retrieve an equivalent amount of content. This is also likely to demand more memory space for local storage of XML. In addition, more time will also be required for the XML parser to be able to process the stream. XML optimization generally produces results showing the relevant information that one should manipulate. With this information, an XML produce is able to decide whether to utilize the available XML automation tools or apply transformation techniques in accordance with the set rules of operation. Other producers could even find it appropriate to define the entire schema of the XML metadata.
XML Performance Improvement Approaches
There are a number of techniques through which XML can be tuned to perform much higher than it is doing today. XML documents can be used to specify the number of character encoding in the XML declaration provided. To achieve maximum performance, developers can use US ASCII as the encoding in the XML documents. XML documents that have been developed using the ASCII characters are usually much easier and faster to parse compared to other standards. An XML document encoded in the UTF-8 standard usually has more ASCII characters. Therefore, some parses tend to perform in the same way as they would perform is the ASCII standards were used.
Another strategy that can be used to improve performance is the reduction of the number of new lines as well as the number of whitespaces contained in the document. To make the editing operations easier and more convenient, developers usually tend to organize their documents into lines. Parsing dependent on the number of characters and the overall performance of the XML document is dependent on the number of characters. If a developer adds more whitespaces, the parser ends up processing more characters, and this affects its overall performance. One should avoid using namespaces unless they are absolutely required.
XML can also be tuned to perform in a better way through the use of string internalization techniques. Setting the SAX to true ensures that the parser is instructed to report various XML names and namespaces of the target URLs as internalized strings. Turning on this feature helps to accelerate the equality strings. While in operation, rather than making calls to the equal attribute which makes comparisons between characters, one can easily compare the names reported by the parser against constant string values.
Another optimization method that can be used to improve the performance of XML documents is switching of the content handlers. The most common problem experienced by developers when processing large vocabularies of XML is that they may end up with a large number of
else statements in the callback. Registering a new content handler during a parse could help in reducing both the complexity and the length of the callback.
Developers usually experience problems with the processing of XML documents containing a large number of references to external entities. For each of the entity with an external reference, the parser is expected to look for the resources from the outside world, locate it and read it. The process is even difficult when the resources are not available on the hard disk, and the parser has to open the file to read it. The performance of such XML documents can be improved by loading the entities into the memory of the entity resolver. The entity resolver should be written in such a way that it is able to catch the content of the entity the first time it reads it. Instead of having to incur the retrieval penalty twice, the application will only incur this cost.
In instances where one may not be interested in processing the external entities, it is advisable to apply techniques that will help bypass the unnecessary information and hence improve the performance of the XML. If the features that enable processing of these entities are disabled and the same features encountered, the SAX parser does not report the content of the entity. I will rather report the name of the entity as a skipped entity in the call back of the content handler. If the developer is not interested in processing this information, he can turn them off to optimize the process.
XML optimization can also be achieved by closely checking the node operations on the DOM. Several types of nodes are defined by the DOM including both the attribute and elements. Before retrieving attributes, it is important to perform query operations to determine whether the node contains any attributes. If the attributes are available, the node can be cast to the element node and the
get attribute method used to obtain the list of attributes. This approach helps to avoid unnecessary casting of the node to the elements thus creating an empty name node map. The
normalizeDocument method used in DOM level 3 can also be used to optimize performance during the validation. However, it can be quite expensive because of the availability of a large number of namespaces. Therefore, the parser has to check all the available namespaces when processing the document.
The choice of the parser configuration also has a major impact on the performance of the XML document. The default configuration supports schema validations in XML 1.0/ 1., DTD and W3C XML. If the XML document does not require any validation, improved performance can be achieved through the use of parser configurations that do not support validation. One can set the code to override the default configuration without changing the existing classes. For instance, the system property can be set to use
org.apache.xerces.xni.parser.XMLParserConfiguration to point towards the intended configuration.
The Future of XML as a Powerful Type Message
In my view, XML will remain a powerful type of message due to the nature of its functions. A large number of data structures for the in-house systems are best implemented using XML. The language has a number of characteristics that make the language of choice for data storage. Unlike other languages, XML is primarily hierarchical. This means that it can support data that is primarily hierarchical. Secondly, it has a degree of flexibility especially in the development of various schemas. It can be rigid at the nodes and loose on other nodes. XML language is also evolving rapidly. Unlike some languages that require total migration of old schemas to fit the new developments, XML only requires the modification of the old schema to accommodate the new release.
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