Error "missing XML object" [unsolved]

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Error "missing XML object" [unsolved]

Postby jd2066 » 05 Aug 2007, 02:20

Hi,
I'm getting the error "Could not display article (missing XML object)" a lot when I click an article in a feed list.
I can click the article again a few times, it will load the article and clicking the next couple articles works but then I get the error again and then the problem starts again.
Justin

Edit:
A couple notes:
1. I had to shorten the title of this post as the full title gave an SQL error.
2. I have switched ttrss to postgresql since my last post.
Last edited by jd2066 on 06 Aug 2007, 09:53, edited 3 times in total.

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Postby fox » 05 Aug 2007, 10:09

This could be caused by network problems. Are you sure you don't have anything wrong with your connectivity to the server w/ tt-rss - e.g. lost packets, etc.?

Another thing - what browser, version of PHP, etc. are you using?

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Postby jd2066 » 05 Aug 2007, 23:47

fox wrote:This could be caused by network problems. Are you sure you don't have anything wrong with your connectivity to the server w/ tt-rss - e.g. lost packets, etc.?

Another thing - what browser, version of PHP, etc. are you using?

I don't think there is anything wrong with my connectivity to the server, I just pinged it and didn't have any packet loss. My server is a local one within the same room as my laptop at the moment, both are plugged into the same router.
My server runs all the following:
Apache 2.0.58
PHP 5.2.3
Postgresql 8.2.4
ttrss SVN version
Justin

Edit:
I just noticed sometimes when I click an article it displays in the preview pane for about 1 second and then is replaced by the error.

Edit 2:
The browser is Mozilla Firefox 2.0.0.6
I just tried in Internet Explorer 7 and got an error popup when I logged in:
"Exception: [object Error]
Function: init_second_stage()"

Edit 3:
I just downloaded the latest tar file and put it on my server and now it works in IE7.

Edit 4:
I just remembered I had mod_cband to limit file downloads from my server.
It appears it also was causing connection problems with ttrss.

Edit 5:
It appears this still happens sometimes.
I also get "Please wait until operation finishes." sometimes too.
Now I'm getting problem where nothing happens when I click an article.
My best guess is it's still performance problems.
My only other guesses would:
1. A problem with using a converted mysql export in postgresql.
2. Performance problems caused other services like vmware on my server though top doesn't show anything using thaty much cpu.

Edit 6:
I turned on debug mode, clicked a few articles until the error appeared again.
The log is at: http://jd2066.googlepages.com/ttrssdebug.log
It appears it may be a problem with article caching and the xml control.

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Postby fox » 06 Aug 2007, 20:14

What is your article database size? Is it a lot? Because of prefetching, loading headlines also pulls some articles along the way which adds to the overhead.

If your database is big, you'll probably have to tweak PGSQL because defaults are usually _very_ conservative in memory usage.

Just in case, here is my slightly tweaked PGSQL config from tt-rss dev box (amd64, 1gb ram, not only used for tt-rss).

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Postby jd2066 » 07 Aug 2007, 10:23

fox wrote:What is your article database size? Is it a lot?

It's about 2.7 GB.
fox wrote:Just in case, here is my slightly tweaked PGSQL config from tt-rss dev box (amd64, 1gb ram, not only used for tt-rss).

I tried using that config and it may have helped a little bit but I'm still getting errors.
It's weird, I can click a few articles in a row and it will work just fine, then I click another and get an XML error or a "Please Wait" message.
Justin

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Postby fox » 07 Aug 2007, 11:36

You'll have to tweak further, my database is about 4 times smaller. :)

Here are some relevant keywords to get you started.

[url]It's weird, I can click a few articles in a row and it will work just fine, then I click another and get an XML error or a "Please Wait" message.[/url]

Don't forget about prefetching. When articles are ready in cache they show up fine.

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Postby jd2066 » 08 Aug 2007, 05:40

fox wrote:Don't forget about prefetching. When articles are ready in cache they show up fine.

Is there a way to disable the prefetching to see more consistent results?
Justin

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Postby fox » 08 Aug 2007, 08:50

Yep. Comment out contents of cache_inject() function (viewfeed.js:853).

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Postby jd2066 » 09 Aug 2007, 05:24

I tweaked postgresql some more and turned off the caching.
It worked for a little while and then I had problems again.
Right now I have a got a new problem where attempting to go to the ttrss url (http://server/ttrss/tt-rss.php) returns a 0 byte page. I don't know if it's tt-rss, php, apache or what that's causing it but I don't like it.
I think if I can't get this working I may just have to use something like Google Reader (which I don't really like it's UI but it does work).
Justin

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Postby fox » 09 Aug 2007, 10:53

Right now I have a got a new problem where attempting to go to the ttrss url (http://server/ttrss/tt-rss.php) returns a 0 byte page.


I have no idea how PGSQL tweaking can cause that. Did you change something else?

I think if I can't get this working I may just have to use something like Google Reader (which I don't really like it's UI but it does work).


Well, you have a large database. Maybe tt-rss just doesn't scale this way, especially without serious PGSQL tweaking.

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Postby jd2066 » 09 Aug 2007, 12:55

fox wrote:I have no idea how PGSQL tweaking can cause that. Did you change something else?

Nothing I can think of at the moment but I guess something must have changed.

fox wrote:Well, you have a large database. Maybe tt-rss just doesn't scale this way, especially without serious PGSQL tweaking.

I suppose so. I'm starting to wonder weather anything does scale that way. Maybe I just need to set the auto expire to 1 day instead of 30 and use it that way.
Justin

Edit:
Looking at the apache error log appearently the 0 byte problem is a Segmentation fault which still doesn't help much.

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Postby fox » 09 Aug 2007, 14:07

Are you sure there is nothing wrong with your server, software or hardware wise?

Apache should not die like that. You could have been looking for the source of your problems in the wrong place (Apache segfaulting would produce errors in tt-rss just as well).

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Postby jd2066 » 10 Aug 2007, 12:24

fox wrote:Are you sure there is nothing wrong with your server, software or hardware wise?

There is nothing wrong with my server that I know of besides this.
I mean there a few things like virtual machines being slow and Java not working but those should be unrelated.
Justin

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Postby fox » 10 Aug 2007, 13:40

Still, in my experience Apache segfaults can (and usually do) indicate some underlying problem or misconfiguration of PHP and such. I would investigate that if I were you.

You have mentioned Java and virtual machines, are you sure you don't run into memory allocation limits or something now with tweaked for bigger working set PGSQL?

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Postby jd2066 » 10 Aug 2007, 14:15

fox wrote:You have mentioned Java and virtual machines, are you sure you don't run into memory allocation limits or something now with tweaked for bigger working set PGSQL?

It appears that was the case. I just reverted to my old pgsql config file and now ttrss loads.
Justin

Edit:
I decided to dump my existing ttrss database and start again (backing up my feed list too) as I think my existing db may have had problems from my starting out with a converted mysql dump.
I'll how it works during the next month and if I still have problems I will post again.
Last edited by jd2066 on 11 Aug 2007, 08:43, edited 1 time in total.


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