Efficient searching in a large XML file for specific elements

Hi
How can I search in a large XML file for a specific element efficiently (fast and memory savvy?) I have a large (approximately 32MB with about 140,000 main elements) XML file and I have to search through it for specific elements. What stable and production-ready open source tools are available for such tasks? I think PDOM is a solution but I can't find any well-known and stable implementations on the web.
Thanks in advance,
Behrang Saeedzadeh.

The problem with DOM parsers is that the whole document needs to be parsed!
So with large documents this uses up a lot of memory.
I suggest you look at sometthing like a pull parser (Piccolo or MPX1) which is a fast parser that is program driven and not event driven like SAX. This has the advantage of not needing to remember your state between events.
I have used Piccolo to extract events from large xml based log files.
Carl.

Similar Messages

How to search XML file for specific attributes ...

Hi, Im trying to design a XML driven billboard. Is there an easy way to seach attributes of all elements using DOM parser and return the element with attribute that matched search criteria?

Yes. Are you using jsdk1.4? If true then look at the XPathAPI.
I wrote a package for working with XML vocabularies. If you are interested on it, here is an example that uses amic-util.jar to find nodes with the id-user attribute:
XmlReader xr = new XmlReader("vocabulary.xml");
NodeSet ns = new XPathFinder(xr).findNodes("*[@id-user]");
while(ns.hasNextNode()) {
XmlReader node = ns.nextNode();
}Send me an e-mail and I will send you back the amic-util.jar and the javadocs.

Validating large xml files

In our application we have a requirement to validate large xml file (around 40 mb) against a simple schema file.
I have tried all options(Sax and Dom) mentioned in below article on sun site -
http://java.sun.com/developer/EJTechTips/2005/tt1025.html
but with all of these approches the validation process just hangs for hours.
Even i am running my test case for this validation by allocating 1 GB memory to test case, on latest processor(core-2 duo) but still it just hangs and returns after a long duration.
If needed i can provide sample test case, schema file and xml file.
Please help me to know if its a problem with JAXP 1.3 Schema Validation Framework (SVF) to handle large files, or if there is any other efficient way of validating large xml file.
Regards
Rahul

you may want to split the XML to 10MB each and parse the XML's separately or store in a database and read the XML using XQuery.
I am sure there may be better ways to do this, will see experts opinions here.

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

1. Is there a way to import large XML files into HANA efficiently?
2. Will it process it node by node or the entire file at a time?
3. Are there any data services provided to do this?
This for a project use case i also have an requirement to process bulk XML files, suggest me to accomplish this task

Hi Patrick,
I am addressing the similar issue. "Getting data from huge XMLs into Hana."
Using Odata services can we handle huge data (i.e create schema/load into Hana) On-the-fly ?
In my scenario,
I get a folder of different complex XML files which are to be loaded into Hana database.
Then I gotta transform & cleanse the data.
Can I use oData services to transform and cleanse the data ?
If so, how can I create oData services dynamically ?
Any help is highly appreciated.
Thank you.
Regards,
Alekhya

I want to load large raw XML file in firefox and parse by DOM. But, for large XML file the firefox very slow some time crashed . Is there any option to increase DOM handling memory in Firefox

Actually i am using an off-line form to load very large XML file and using firefox to load that form. But, its taking more time to load and some time the browser crashed. through DOM parsing this XML file to my form. Is there any option to increase DOM handler size in firefox

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.

What are the best tools for opening very large XML files and examining the tree and confirming they are valid?

I am generating some very large XML files (600,000+ lines, 50MB+ characters). I finally have them all being valid XML and valid UTF-8.
But the files are so large Safari and Chrome will often not open them. FireFox will though.
Instead of these browsers, I was wondering if there are there any other recommended apps for the Mac for opening and viewing the XML, getting an error message if they are not valid for some reason and examing the XML tree?
I opened the file in the default app for XML which is Xcode, but that is just like opening it in a plain text editor. You can't expand/collapse the XML tree like you can with a browser, and it doesn't report errors.
Thanks,
Doug

Hi Tom,
I had not seen that list. I'll look it over.
I'm also in touch with the developer of BBEdit (they are quite responsive) and they are willing to look at the file in question and see why it is not reporting UTF-8 errors while Chrome is.
For now I have all the invalid characters quashed and things are working. But it would be useful in the future.
By the by, some of those editors are quite pricey!
doug

What program would I use in creative cloud to search a large audio file for sounds.

I have sleep apnea and want to search large audio files for my snoring. what program would I use and any other tips would be great.
thank you

Moving this discussion to the Audition forum.
VTX1300C Audition is the sound editing program included with your Creative Cloud Membership. The users in this forum may have some additional Audition specific tips or an alternate workflow which you can utilize.

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 ?
All help/suggestions appreciated.

Forgot to add:
after carrying out validation the data is put into some RDBMS tables.
One approach would be to convert the XML files into SQL Loader compatible flat files (using a tool). Load these flat files into staging tables. Perform business validations on staging table data and then finally move the data into the main tables. All the validating logic could either be in stored procedures or java code.
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.

Loading, processing and transforming Large XML Files

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.
The difference from what we have in our hands to other related issues posted is that the XML isn't big because it has a largly branched tree of data, but rather because it includes large base64-encoded files in the xml itself. The size of the 'clean' xml is relatively small (a few hundred bytes to some kilobytes).
We had to deal with transferring the xml to our application using a webservice, loading the xml to memory in order to read values from it, and now we also need to transform the xml to a different format.
We solved the webservice issue using XFire.
We solved the loading of the xml using JAXB. Nevertheless, we use string manipulations to 'cut' the xml before we load it to memory - otherwise we get OutOfMemory errors. We don't need to load the whole XML to memory, but I really hate this solution because of the 'unorthodox' manipulation of the xml (i.e. the cutting of it).
Now we need to deal with the transofmation of those XMLs, but obviously we can't cut it down this time. We have little experience writing XSL, but no experience on how to use Java to use the XSL files. We're looking for suggestions on how to do it most efficiently.
The biggest problem we encounter is the OutOfMemory errors.
So I ask several questions in one post:
1. Is there a better way to transfer the large files using a webservice?
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.
I assume this is an important piece of information: We currently use JDK 1.4.2, and cannot upgrade to 1.5.
Thanks for the help.

I think there may be a way to do it.
First, for low RAM needs, nothing beats SAX. as the first processor of the data. With SAX, you control the memory use since SAX only processes one "chunk" of the file at a time. You supply a class with methods named startElement, endElement, and characters. It calls the startElement method when it finds a new element. It calls the characters method when it wants to pass you some or all of the text between the start and end tags. It calls endElement to signal that passing characters is over, and to let you get ready for the next element. So, if your characters method did nothing with the base-64 data, you could see the XML go by with low memory needs.
Since we know in your case that the characters will process large chunks of data, you can expect many calls as SAX calls your code. The only workable solution is to use a StringBuffer to accumulate the data. When the endElement is called, you can decode the base-64 data and keep it somewhere. The most efficient way to do this is to have one StringBuffer for the class handling the SAX calls. Instantiate it with a big enough size to hold the largest of your binary data streams. In the startElement, you can set the length of the StringBuilder to zero and reuse it over and over.
You did not say what you wanted to do with the XML data once you have processed it. SAX is nice from a memory perspective, but it makes you do all the work of storing the data. Unless you build a structured set of classes "on the fly" nothing is kept. There is a way to pass the output of one SAX pass into a DOM processor (without the binary data, in this case) and then you would wind up with a nice tree object with the rest of your data and a group of binary data objects. I've never done the SAX/DOM combo, but it is called a SAXFilter, and you should be able to google an example.
So, the bottom line is that is is very possible to do what you want, but it will take some careful design on your part.
Dave Patterson

Query in a large xml file

Hello,
I'm trying to work with very large xml files which are created from csv files. These files may be very large - up to 1 GB ! Untill now I have managed to do several validations on these big xml files, and the only thing that works for me is SAX parser, DOM is out of the question because it fills up memory.
My next task is to do queries on these files, smth like:
select field1,field2 from file.xml
where field3 = 'A'
and (fileld4>'B' or field1='C')
order by field2.
I searched the net about finding out how to make queries on xml files (since I have never done queries on xml before), but I couldn't find which "query language" is best for large files. If I use XPath (XSLT) will that not cause me memory problems because XSLT represents the file as a memory object?
My idea is to parse the file with SAX and check every row if it fits the where condition and then write it immediately to a result xml file. But validating the where statement can be very complicated without using some tool. Also the order by statement is another problematic issue.
Does anyone have some more intelegent ideas about how I can do this? Please help! :(
The xml file looks like this:
<doc>
<row id ="1">
<column id="1" name="column1">value</column>
<column id="N" name="columnN">value</column>
</row>
<row id ="M">
<column id="1" name="column1">value</column>
<column id="N" name="columnN">value</column>
</row>
</doc>

Hi all,
Thank you very much for your replies.
First, saxon didn't work because it uses an in-memory parser, and that is what I was trying to avoid.
Different database is also out of the question, because the customer insist on XML, and also there are some files that can never be converted to a database table, because eventually with some transformations thay are changed and are not completely like the standard csv format.
I think that maybe http://exist.sourceforge.net is the rigth solution for me, but I will probably try it in the next version of my project.
For now I have managed to make the project with only SAXParser and a lot of back - end programming and it works ok, althoug it was very hard to make it, and will be harded to maintain, so I will try to look at the eXist project.
Thanks everyone for the help.

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

Import Large XML File to Table

I have a large (819MB) XML file I'm trying to import into a table in the format:
<ROW_SET>
<ROW>
<column_name>value</column_name>
</ROW>
<ROW>
<column_name>value</column_name>
</ROW>
</ROW_SET>
I've tried importing it with xmlsequence(...).extract(...) and ran into the number of nodes exceed maximum error.
I've tried importing it with XMLTable(... passing XMLTYPE(bfilename('DIR_OBJ','large_819mb_file.xml'), nls_charset_id('UTF8'))) and I gave up after it ran for 15+ hours ( COLLECTION ITERATOR PICKLER FETCH issue ).
I've tried importing it with:
insCtx := DBMS_XMLStore.newContext('schemaname.tablename');
DBMS_XMLStore.clearUpdateColumnList(insCtx);
DBMS_XMLStore.setUpdateColumn(insCtx,'column1name');
DBMS_XMLStore.setUpdateColumn(insCtx,'columnNname');
ROWS := DBMS_XMLStore.insertXML(insCtx, XMLTYPE(bfilename('DIR_OBJ','large_819mb_file.xml'), nls_charset_id('UTF8')));
and ran into ORA-04030: out of process memory when trying to allocate 1032 bytes (qmxlu subheap,qmemNextBuf:alloc).
All I need to do is read the XML file and move the data into a matching table in a reasonable time. Once I have the data in the database, I no longer need the XML file.
What would be the best way to import large XML files?
Oracle Database 11g Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
"CORE     11.2.0.1.0     Production"
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production

This (rough) approach should work for you.
CREATE TABLE HOLDS_XML
        (xml_col XMLTYPE)
      XMLTYPE xml_col STORE AS SECUREFILE BINARY XML;
INSERT INTO HOLDS_XML
VALUES (xmltype(bfilename('DIR_OBJ','large_819mb_file.xml'), nls_charset_id('UTF8')))
-- Should be using AL32UTF8 for DB character set with XML
SELECT ...
FROM HOLD_XML HX
       XMLTable(...
          PASSING HX.xml_col ...)How it differs from your approach.
By using the HOLDS_XML table with SECUREFILE BINARY XML storage (which became the default in 11.2.0.2) we are providing a place for Oracle to store a parsed version of the XML. This allows the XML to be stored on disk instead of in memory. Oracle can then access the needed pieces of XML from disk by streaming them instead of holding the whole XML in memory and parsing it repeatedly to find the information needed. That is what COLLECTION ITERATOR PICKLER FETCH means. A lot of memory work. You can search on that term to learn more about it if needed.
The XMTable approach then simply reads this XML from disk and should be able to parse the XML with no issue. You have the option of adding indexes to the XML, but since you are simply reading it all one time and tossing it, there is no advantage to indexes (most likely)

Parsing large xml file and display using swing

Hi all,
I want to read a large xml file and display graphically in swing as a tree structure.
I implemented it and works fine for files of 5MB size after increasing the jvm heap size (-Xmx). If the file size is larger than 5MB it throws out of memory error. I'm creating a custom datastructure from the xml and I'm using sax parsing.
After displaying the datastructure, the user could do some operation on this, like search etc.
Can any of you suggest a method, to support larger files ? What I'm looking for is create the datastructure in file system, rather than in memory.
Any other tips for memory management would be greatly appreciated
Thanks in Advance.
Nisha

Use a memory-mapped file?
http://javaalmanac.com/egs/java.nio/CreateMemMap.html

Help in creation of XML file for IDOC postings

Hi All,
Need help if anyone has knowledge/experience in creating XML files for IDOC processing.
We need to design an input file (in XML format) for creation of IDOCu2019s for purchase Invoices through Interface.
We have an existing input file, which is working correctly. We are trying to modify this existing input file for a new Tax Code (Non-deductible inverse tax liability). This tax code is working fine for manual postings. But, through IDOC, tax postings are not correctly triggering.
Could you please confirm if any one has experience on this, so that I can share more details for resolving.
Thanks & Regards,
Srini

Hello,
you can use CALL TRANSFORMATION id, which will create a exact "print" of the ABAP data into the XML.
If you need to change the structure of XML, you can alter your ABAP structure to match the requirements.
Of course you can create your own XSLT but that is not that easy to describe and nobody will do that for you around here. If you would like to start with XSLT, you´d better start the search.
Regards Otto

Efficient searching in a large XML file for specific elements

Similar Messages

Maybe you are looking for