Handling large xml files using tree

hi,
I have an issue with a tree having xml data as the
dataprovider. The front end makes a http service call to a servlet
at a server to get the string representation of an xml file . The
string format is changed to xml in the flex front end and made to
display as a tree. Everything works fine when the xml data is small
but as xml data grows in size the handling of data into the tree is
very slow and the application does not respond sometimes..Can
anyone tell me how i could get this issues solved or is there a
better way to solve it. Or is there a way that the tree gets
displayed only when all the nodes or loaded properly and there are
no lags while user tries to navigate through it..
Thanks in advance...

Hi,
Did you get a reply for this? If so,can you pl share it with me too?
i need to send a XML +also need to set 2 parameters over Http Post to a servlet...
Thanks,
-uday.
[email protected]

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NodeList list=doc.getElementsByTagName("Information");
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Node newsampTopNode = doc.createElement("Top");
Text tnNode = doc.createTextNode("0.50");
newsampTopNode.appendChild(tnNode);
Element newsampRef = doc.createElement("Ref");
Text tsr = doc.createTextNode("0");
newsampRef.appendChild(tsr);
Element newsampType = doc.createElement("Type");
Text tt = doc.createTextNode("z");
newsampType.appendChild(tt);
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newsampNode.appendChild(newsampRef);
newsampNode.appendChild(newsampType);
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Hi all,
I realize this may have been asked before, but searching the history of the forum isn't easy, considering it's not always a safe bet which words to use on the search.
Here's the situation. We're trying to load and manipulate large XML files of up to 100MB in size.
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2. Is there a better way to load and manipulate the large XML files?
3. What's the best way for us to transform those large XMLs?
4. Are we missing something in terms of memory management? Is there a better way to control it? We really are struggling there.
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Dave Patterson

Is JAXB suitable for large XML files ?

Hi,
I have a very large XML file (~700 MB) (schema available). I need to unmarshall this into java objects and carry out some (business validation rules) on it.. These buisness rules may involve validating data from content objects that correspond to different sections of this large XML file.
I am uncertain whether JAXB will help me here. (just started on it) Does JAXB build the entire content tree for the XML document during Unmarshaller.unmarshall ? Is there anyway of asking it to build content objects on demand as opposed to building the whole content tree immediately ?
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Forgot to add:
after carrying out validation the data is put into some RDBMS tables.
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The above is very long-winded. It would be great if JAXB can handle very large XML files (without loading the whole XML file into memory) so that business validations can be done by java, without any intermediate format conversion.
I hope the above is somewhat clear.

Is there a way to import large XML files into HANA efficiently are their any data services provided to do this?

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3. Are there any data services provided to do this?
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Hi Patrick,
I am addressing the similar issue. "Getting data from huge XMLs into Hana."
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Best technology to navigate through a very large XML file in a web page

Hi!
I have a very large XML file that needs to be displayed in my web page, may be as a tree structure. Visitors should be able to go to any level depth nodes and access the children elements or text element of those nodes.
I thought about using DOM parser with Java but dropped that idea as DOM would be stored in memory and hence its space consuming. Neither SAX works for me as every time there is a click on any of the nodes, my SAX parser parses the whole document for the node and its time consuming.
Could anyone please tell me the best technology and best parser to be used for very large XML files?

Thank you for your suggestion. I have a question,
though. If I use a relational database and try to
access it for EACH and EVERY click the user makes,
wouldn't that take much time to populate the page with
data?
Isn't XML store more efficient here? Please reply me.You have the choice of reading a small number of records (10 children per element?) from a database, or parsing multiple megabytes. Reading 10 records from a database should take maybe 100 milliseconds (1/10 of a second). I have written a web application that reads several hundred records and returns them with acceptable response time, and I am no expert. To parse an XML file of many megabytes... you have already tried this, so you know how long it takes, right? If you haven't tried it then you should. It's possible to waste a lot of time considering alternatives -- the term is "analysis paralysis". Speculating on how fast something might be doesn't get you very far.

How to parse large xml file

I need to parse large xml file which contains following tag. The size of the file is upto 10MB-50MB or more.
<departments>
<department>
<a_depart id="124">
<b_depart id="Bss_253">
<bss_depart id="253">
<attributes>
<name_one>abc</name_one>
</attributes>
</bss_depart id="253">
</b_depart id="Bss_253">
</a_depart id="124">
</department>
<department>
<a_depart id="124">
<b_depart id="Bss_254">
<mss_depart id="253">
          <attributes>
          <name_one>abc</name_one>
          <name_two>xyz</name_one>
          </attributes>
     </mss_depart>
     </b_depart>
</a_depart>
</department>
<department>
<a_depart id="124">
<b_depart id="Bss_254">
<mss_depart id="255">
          <attributes>
          <name_one>abc</name_one>
          <name_two>xyz</name_one>
          </attributes>
     </mss_depart>
     </b_depart>
</a_depart>
</department>
<department>
<a_depart id="125">
<b_depart id="Bss_254">
<mss_depart id="253">
          <attributes>
          <name_one>abc</name_one>
          <name_two>xyz</name_one>
          </attributes>
     </mss_depart>
     </b_depart>
</a_depart>
</department>
I want to get the infomation for that xml file. like mss_depart id=233, building xpath dyanmically for every id and loading
that using dom4j. which is very very slow.
Is there any other solution for that to read the data using sax parser only.
I want to execute the xpath or data for the following way.
//a_depart/@id ------> all the ids of a_depart tags if it returns 3 values say 123,124,125
after that i want to execute
//a_depart[@id='123']/b_depart/@id like this ...to retrive the values of all the levels ...
     I am executing following xpath for every unique ids at all levels.
     List l = doc.selectNodes(xPathForID);
     List l1 = doc.selectNodes(xPathForAttributes+attributes.get(j)+"/text()");
But it is very slow and taking lot of time.
Is there any other way to solve this problem. If any please mail me it is urgent.
I am using jdk1.4 and jdk1.5
Is there any support for sax parser to execute xpath in jdk1.5 direclty, with out using dom4j
Thanks in advance....

I doubt you will find a preexisting solution to your problem.
SAX is usually recommended for processing big files (where "big" is undefined"). It works on big files by avoiding the messy problem of storing the data -- that is left as an exercise to you.
DOM (and its variants) works by building a Document object as the head of the tree of objects for the entire contents. With DOM, you can then use XPath, because there is something to search that is already in memory. To use XPath, you seem to have two choices, build a DOM-ish tree, or if you can find an XPath processor (I'm not sure if one exists) that can process the XML file directly, but it will be slow, since you are looking for "all" occurences of an attribute, and this means you have to read the entire file each time.
It might be worth exploring a hybrid approach -- use SAX to get some information, and build your own objects to store the data. Maybe a HashMap as the main index. But, that will keep you from using XPath, since you do not have the data structures it expects.
A third alternative would be to look at JAXB. It builds Java code from a Schema of your data and then when you import the data, it creates the necessary objects and fills in values. But, I don't think XPath woll work there either.
Dave Patterson

Problem with parsing large xml files

Hello All,
I am parsing a large xml file of 20MB and I use DocumentBuilder.parse(File). This method works for small xml files with size less than 20MB but the application hangs and doesn't through any error message when parsing 20MB xml files. Please let me know what I have to do at this point ?
Thanks & Regards,
Kumar.

Well... i can't agree.
If you have such structure:
<task>
<task/>
<task>
     <task>
        <task/>
     </task>
     <task/>
</task>
</task>
...you may always keep stack of tasks (at startElement push to top, and at endElement pop), so at every leaf of tree you will have all parents of that leaf.
for such structure:
<task id="1" parent="0"/>
<task id="2" parent="1"/>
<task id="3" parent="1"/>
<task id="4" parent="2"/>
<task id="5" parent="3"/>
...it will be much faster to go thro document by sax several times to build tree of tasks, than to load all document into memory...

Problems with Large XML files

I have tried increasing the memory pool using the -mx and -ms options. It doesnt work. I am using your latest XML parser for Java v2. Please let me know if there are some specific options I should be using.
Thanx,
-Sameer
We have a number of test files that are that size and it works without a problem. However using the DOMParser does require significantly more memory than your doc size.
What is the memory configuration of the JVM that you are running with? Have you tried increasing it? Are you using our latest version 2.0.2.6?
Oracle XML Team
Is there a restriction on the XML file size that can be loaded into the parser?
I am getting a out of memory exception reading in large XML file(10MB) using the commands
DOMParser parser = new DOMParser();
URL url = createURL(argv[0]);
parser.setErrorStream(System.err);
parser.setValidationMode(true);
parser.showWarnings(true);
parser.parse(url);
Win NT 4.0 Server
Sun JDK 1.2.2
===================================
Error output
===================================
Exception in thread "main" java.lang.OutOfMemoryError
at oracle.xml.parser.v2.ElementDecl.getAttrDecls(ElementDecl.java, Compi
led Code)
at java.util.Hashtable.<init>(Unknown Source)
at oracle.xml.parser.v2.DTDDecl.<init>(DTDDecl.java, Compiled Code)
at oracle.xml.parser.v2.ElementDecl.getAttrDecls(ElementDecl.java, Compi
led Code)
at oracle.xml.parser.v2.ValidatingParser.checkDefaultAttributes(Validati
ngParser.java, Compiled Code)
at oracle.xml.parser.v2.NonValidatingParser.parseAttributes(NonValidatin
gParser.java, Compiled Code)
at oracle.xml.parser.v2.NonValidatingParser.parseElement(NonValidatingPa
rser.java, Compiled Code)
at oracle.xml.parser.v2.ValidatingParser.parseRootElement(ValidatingPars
er.java:97)
at oracle.xml.parser.v2.NonValidatingParser.parseDocument(NonValidatingP
arser.java:199)
at oracle.xml.parser.v2.XMLParser.parse(XMLParser.java:146)
at TestLF.main(TestLF.java:40)
null

You might try using a different JDK/JRE - either a 1.1.6+ or 1.3 version as 1.2 in our experience has the largest footprint. If this doesn't work can you give us some details about your system configuration. Finally you might try the SAX interface as it does not need to load the entire DOM tree into memory.
Oracle XML Team

Handling large xml files using tree

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