Re: [xml] libxml2, python, reducing memory consumption?

[Daniel Veillard <veillard redhat com>]

On Tue, Dec 23, 2003 at 11:26:34AM -0800, Robin Dunn wrote:
> I have a tool that reads a number of input documents, does some 
> processing and then builds and writes a new document, but it uses about 
> 500MB of RAM when it runs so I am trying to find ways to reduce the 
> memory footprint.  I know that using SAX instead of DOM would do it for 
> me, but the nature of what needs to be done just screams for DOM and 
> XPath do that is the way I have done it.

  Try the xmlReader and expand only the subparts where your really need to
do XPath queries. See the end of http://xmlsoft.org/xmlreader.html#Mixing

> The total size of the input documents is about 100M and each one is 
> about 4-8M.  The total size of the output document is about 1.5M.
> 
> I added a call to doc.freeDoc after I am done with each input document 
> before loading the next one, but that doesn't seem to affect memory 
> consumption at all.

  Then something is wrong...

> Then instead of building the whole output tree in memory I tried only 
> building only the dozen or so children of the root element and 
> serializing each to a file and then calling node.freeNode, but there was 
> still no improvement.
> 
> What am I missing?

  No idea, doc.freeDoc() do free the underlying C structures associated
to the document. Maybe there is something else ...

Daniel

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