Reading XML files is 'sometimes' slow

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Hi,

Now before I start explaining my issue, I have read a few articles about issues reading XML files over a GB in size. That is not my issue, or so I believe.

I have two XML files, both about 4MB in size, file A with roughly 10000 elements, file B with 1500. The specific elements are differing in size.

Now quite bizarrely file A takes a fraction of a second to be read using DataSet.ReadXML and yet file B takes over two minutes!

Any one found anything like this before? Am I missing something obvious?

The structure of the XML files is thus

XML

<?xml version="1.0" standalone="yes"?>
<NewDataSet>
    Schema definition here
    <element>
        <id>1</id>
        <datafield1>xxxx</datafield1>
        <datafield2>xxxx</datafield2>
        ....
    </element>
    <element>
        ....
</NewDataSet>

I apologise if my use of the term 'element' is incorrect, alas I am a self-taught C# coder.

Any help is greatly appreciated

Cheers

Posted 27-Oct-12 14:07pm

John_Black

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John_Black 27-Oct-12 22:29pm

Something I have noticed is that my application is significantly quicker when compiled.

Reading the specific xml file only seems slow when running the app within Visual Studio Express either in debug or release mode.

Max Vagner 31-Oct-12 4:34am

What are you using to read XML? Is file located locally? Try System.Xml.Linq.XElement.Load()

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Kuthuparakkal · Answer 1 · 2012-10-27T15:50:00

Solution 1

Try specifying XmlReadMode, this would increase performance.

C#

myDS.ReadXml("C:\\Test\\input.xml", XmlReadMode.ReadSchema);

Posted 27-Oct-12 15:50pm

Kuthuparakkal

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John_Black 27-Oct-12 22:22pm

Thanks for your quick response, however your suggestion made no change in the speed of the ReadXML command unfortunately.

MT_ · Answer 2 · 2012-10-28T00:12:00

Hi,
Since you are saying both the files are around 4 MB, but one has 10000 elements whereas second has 1500 elements, I assume, the structure is different which might be causing multiple table reading.

You may like to try calling BeginLoadData before calling ReadXml method.

C#

foreach (DataTable dataTable in dataSet.Tables)
   dataTable.BeginLoadData();

dataSet.ReadXml("file.xml"); 

foreach (DataTable dataTable in dataSet.Tables)
   dataTable.EndLoadData();

More details and source of the above code is MSDN at http://msdn.microsoft.com/en-us/library/fx29c3yd.aspx[^]

Hope that helps

- Milind