[fpc-pascal] How to save a huge XML?

[Michael Van Canneyt]

On Tue, 18 Jun 2013, Marcos Douglas wrote:

> On Tue, Jun 18, 2013 at 10:44 AM, Michael Van Canneyt
> <michael at freepascal.org> wrote:
>>
>>
>> On Tue, 18 Jun 2013, Marcos Douglas wrote:
>>
>>>> No. The writer already uses a fixed buffer. Your problem is the use of
>>>> TXMLDocument.
>>>
>>>
>>> Ideas? Maybe do what Antonio Fortuny said before?
>>>
>>>>
>>>> Simply put: logging to XML (worse: using DOM) is a VERY bad idea.
>>>
>>>
>>> Well, this is a request of my client. Other process will read this XML.
>>
>>
>> Under no circumstances should you use TXMLDocument for this.
>
> So, where is recommended to use TXMLDocument class?

General XML processing. Small documents.

You should be aware that the DOM always has the whole XML document in memory, 
plus a substantial amount of overhead. This is not something FPC specific, but is 
inherent in the DOM model. (a W3 spec)

Regardles of XML or not: keeping logs in memory is simply a bad idea. 
You can buffer them for performance reasons, but after some time you must write to file.

The DOM model does not allow this.

Michael.