Large Documents tutorial
Processing a large XML files XML persistent storage

## Preliminaries

- The PL varchar variable has a limit of 10Mb.
- This means that variables that may contains a large document for XML processing cannot keep over 10Mb data.
- Using a temp file with xml_persistent does not have this limit.
- The xml_persistent() can process the large documents using the temporary file for storing the data.

## Caution: Paths used in that sample are evaluted in the server file system. Specify correct server filesystem paths.

## Example

- The example converts a file to persistent XML and back to a file.
- The file is then traversed by XSLT and the result is stored into a string output.
- This is then stored into a file.
- The input of the sheet is checked against a DTD.
- The page shows these steps and the lengths of the files and intermediate data.
- The data is an excerpt of dmoz with some extra repetition to make 5MB of data. This is not itself above the varchar limit but is large enough for this example.
- The results can be seen in the result file in the directory.
- The vsp page will show fragments of the data, e.g. part of the first subtree.