173443 - Loading a large xml document results in a hanging browser

Status: RESOLVED INVALID

(Core :: XSLT, defect)

Description

[André Schild]

When loading a large xml document from a file,
then mozilla just seems to freeze.

The attached 6MB sized xml document is a example of this.
Initialy mozilla takes up more memory, but after ~10-20 secs
no more memory seems to be allocated by mozilla, but cpu
utilization stays at 100%. Even after 10 minutes of waiting 
(933MHz CPU, 400MB Memory, w2k) mozilla still seems to freeze.

IE6SP1 on the same system can display the same file correctly,
but it seems that it renders only 10% of the file and renders 
more when we scroll down.

Comment 1

[André Schild]

Attachment: Ziped large xml file (6MB)

Comment 2

[Heikki Toivonen (remove -bugzilla when emailing directly)]

Hmm, I have never seen us hang on XML docs that don't have stylesheets. Could
someone test on smaller chunks of the file to see if we still hang?

Comment 3

[Oliver Klee]

This might be just a severe performance problem with pretty-printing XML ->
maybe not a hang, but just loooooooooooong rendering time.

Comment 4

[Heikki Toivonen (remove -bugzilla when emailing directly)]

It happens even when pretty print is turned off.

Comment 5

[André Schild]

When I turn pretty printing off in the prefs, then it loads and displays under
build 2002100911.

Loading smaller parts of this same xml file works fine.
From the point of view of the user it's not clear if mozilla hangs
or if it just takes ages to display the content. 

André

Comment 6

[André Schild]

Attachment: XML file with 28 items

This is small subset of the original 6MB xml file.
The 6MB file has 15699 logical items (pricecatalog), this one only 28

Comment 7

[André Schild]

Attachment: XML file with 56 items

This is small subset of the original 6MB xml file.
The 6MB file has 15699 logical items (pricecatalog), this one only 56

Comment 8

[André Schild]

Attachment: XML file with 112 items

This is small subset of the original 6MB xml file.
The 6MB file has 15699 logical items (pricecatalog), this one only 112

Comment 9

[André Schild]

I've made some performance tests on a AMD 850MHz WinXP system with build 2002100911.

Displaying the 28 items xml file takes ~20 seconds
Displaying the 56 items xml file takes ~80 seconds
Displaying the 112 items xml file takes ~420 seconds

So it seems that when the filesize (or better number of xml elements) doubles,
it takes 4-5 times more time to display it.

The original 6MB file has 1207 such items (not xml tags), so it probably takes
about 24 hours to display it.

Here my calculations

Items   Secs.   Mins.   Yours   Days
28	20	0.33	0.01	0
56	80	1.33	0.02	0
112	420	7	0.12	0
224	1680	28	0.47	0.02
448	6720	112	1.87	0.08
896	26880	448	7.47	0.31
1792	107520	1792	29.87	1.24

So in fact it doesn't hang, it just takes ages to display it, and (worst) during
this time the whole mozilla doesn't respond to user interactions.
No way to check mails, open a second browser/tab etc.
No way to cancel this long display processing.
No progressbar indicating that he is still doing something.

So for the user mozilla is just hanging.

Comment 10

[Kurt Weinschenker]

Isn't this related to bug #151380, in a sense?

FWIW, I attached a MacsBug stdlog to that bug as Mozilla went around and around.

Pardon me if I'm being silly here.

Comment 11

[Heikki Toivonen (remove -bugzilla when emailing directly)]

This might be a dupe of some XSLT perf bug. But since XSLT & prettyprint are
both Jonas's area, reassigning.

Comment 12

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

I'm going to mark this invalid as there isn't really a hang here. We are well
aware that the XSLT engine is slow and it is one of our highest priorities to
fix that.

I'll move the bug to the XSLT component though, so that we can use the document
for profiling.