Ghost Comments

dadave · 2007-06-23 17:43:37

greetings,

I am part of a collective that’s using TextPattern to host a relatively large online magazine. We’re using the textdrive host to host our site, and have the latest version of textpattern 4.0.4 installed and running smoothly.

However, that being said, we are having a major problem with comments disappearing, or showing up for a while, and then going away, or showing up not at all. It’s a real problem because one, it’s incredibly hard to figure out when or why it’s happening, and also our readers are accusing us of deleting comments and now no one even bothers because it’s such a hassle to get a comment onto an article.

The only solution we’ve tried is making sure that our textdrive server space has room, and also we tried deleting some comments from an article that had over 350 comments in the hopes of freeing up some space. We think it may have worked, but really we don’t know, and we’re still getting accusiations that we’re deleting comments.

This is a very serious issue, that we suspect may be deep in the inner workings of textpattern and we hope that someone out there can give some insight to help us fix it.

thanks.

Sencer · 2007-06-23 18:17:11

When the comments are selected for display, it’s always the same query:

select *, unix_timestamp(posted) as time from txp_discuss where parentid=9 and visible=1

where obviously “9” is replaced by the id of the article for which the comments are to be displayed. It is highly unlikely that fields in the database randomly switch their visibility status. It’s also unlikely that the loops in PHP have gotten so old, that they forget a comment every now and then.

This would make it seem that the following options are left:

Someone with access to the content->comments interface is changing some comment’s visibility status.
There is something going wrong with the Last-Modified header from time to time (you can turn off sending that in the preferences and see if it makes the problem go away). It’s however unclear if this even fits the problem description, because “comments disappearing, or showing up for a while” is extremely vague and makes it sound like a comment that could be seen by a certain user, disappears for that user. That behaviour could not be explained by Last-Modified Headers.
Are you (or your host) using some kind of reverse-proxy in front of the website when things get hectic?

In any case, the problem description has to be more specific for us to suggest likely causes or look deeper into this. Can very spcificly describe 2 or 3 (types of) occurrences of the problem in list form, with each step of the action and by whom and the result. Like:

a) User A submits comment
b) ~ is redirected to page and sees his own comment
c) ~ notices that the comment he responded to earlier is missing.

etc.

Last edited by Sencer (2007-06-23 18:17:41)

reid · 2007-06-23 19:16:24

Sencer wrote:

There is something going wrong with the Last-Modified header from time to time (you can turn off sending that in the preferences and see if it makes the problem go away).

I’d highly recommend turning this preference off and seeing if it fixes the situation. I have a client on Textdrive who was having problems with comments not showing up at the time they were made in a highly active thread, and that preference solved it.

But as Sencer noted, if the problem is comments first appearing and then disappearing, it is likely another issue.

dadave · 2007-06-23 19:50:35

thanks Spencer I am going to compile the information you requested and get some specifics and post them here.

reid wrote:

I’d highly recommend turning this preference off and seeing if it fixes the situation.

We currently have it set to “yes” are there any drawbacks to having it set to “no” ?

Sencer · 2007-06-23 20:46:43

That setting enables the sending of 304 Not Modified headers, which would somewhat cut down on the load and the traffic when the same user requests the same urls again. Basically it i checked whether the content on the page has changed since the timestamp that is provided by the user’s browser, and if it hasn’t, we don’t have to generate the page and simply tell the user’s browser (via the http status code) that he can display the page from the cache.
A Force-refresh (Ctrl-F5) will always request a fresh page (more specifically the browser will not supply a timestamp, so we definitely create afresh page), so if your users try that when a comment is missing, that would also indicate the problem is related to the Last-Modified headers.

dadave · 2007-06-25 01:12:25

Hey Guys,

I am still waiting on concensus to shut off the last-modified preference, in the meantime here is a clearer description as to the problem.

My guess is that the comment problem lies within some glitch between Firefox and Textpattern. I just tested out a comment. I posted it, it showed up on the page after I posted it, and then I clicked “home” and it was gone. I went back to the article and the comment wasn’t there. However, it did show up in textpattern and when I re-opened the page with Safari it was also there. But then I deleted my own comment from textpattern. If this isn’t THE problem, it’s certainly one of the problems.

Hope this helps.

Sencer · 2007-06-25 08:27:56

After you post a comment, you get redirected to a slightly different url with “?commented=1” appended. So that explains why he sees the comment there (it’s a fresh page with a new url). Once he goes back though to the “regular” article page with the old url, he gets the stale page he viewed before – which shouldn’t be happening, unless there’s something screwy with the times.

I’ll try to replicate the behaviour on my textdrive testsite. But if it’s possible I’d also ask you to send me the url to your site (maybe an old article or an “unknown section” or a test installation if you have oone) where I could test the behaviour in case I can’t reproduce it.

Sencer · 2007-06-25 16:14:35

Quick question, because it came up in another thread: You are familiar with the following setting, and it is set to yes?

http://rpc.textpattern.com/help/?item=comment_means_site_updated&lang=en

New comment means site updated

The database keeps track of when the last change to your site has happened. When this setting is set to yes, a new comment will also update this value. This value is for example used for the “Send Last-Modified header”-functionality.

The-Exit · 2007-06-26 20:14:50

I have turned the e-mail and the last modified header on.

A reader of my blog complained about his comment having “disappeared” after submitting. indeed, he had to hit f5.

steps:

enter comment
preview
submit

reader clicks on “home”-button.

the list of recent comments does not display his comment, nor has the comments_count in the article increased.

Last edited by The-Exit (2007-06-27 10:18:17)

Sencer · 2007-06-28 15:36:17

I’ve been trying to reproduce the error but so far had no luck. Neither on my personal site, nor on a testsite on textdrive. And also unsuccesfully Matthias’ site (sorry for the two test-comments). The Last-Modified and caching headers are always correct, I always get the pages I should get, no lags or anything.

The best would be if somebody who can reproduce the error could log the whole conversation between browser and server across the 5-6 pageviews (vieweing, commenting-vieweing etc.) with something like wireshark and send me the file. Maybe I can find more clues for what might be interfering.
( http://wireshark.org/ )

edit: If you can reproduce the wrong behaviour on this site – http://txd.sencer.de/txp405/ – then it’s definitely a client side problem (we’d still try to find a solution of couse).

Last edited by Sencer (2007-06-28 15:38:15)

The-Exit · 2007-06-28 15:39:57

Well, the problem occured on my personal weblog: blog.the-exit.net and not in the hauptstadtblog where you tested. sorry. but so far i couldn’t reproduce this error neither.

Sencer · 2007-06-28 15:46:20

Well the puzling this is this: The last-update time is updated in the database when a comment is submitted (except if a plugin was installed, that bypassed that code, maybe some kind of “live-preview”-plugin may do that). All timestamps used are generated serverside – so the only two solutions are either that the servertime is randomly jumping backwards and forwards, or the browser (or an intermediate proxy) is configured to not always check the validity of the page.
Hence my suggestion that somebody who can reproduce the problem send me a wirehsark/tcpdump log of the conversation.

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#1 2007-06-23 17:43:37

Ghost Comments

#2 2007-06-23 18:17:11

Re: Ghost Comments

#3 2007-06-23 19:16:24

Re: Ghost Comments

#4 2007-06-23 19:50:35

Re: Ghost Comments

#5 2007-06-23 20:46:43

Re: Ghost Comments

#6 2007-06-25 01:12:25

Re: Ghost Comments

#7 2007-06-25 08:27:56

Re: Ghost Comments

#8 2007-06-25 16:14:35

Re: Ghost Comments

#9 2007-06-26 20:14:50

Re: Ghost Comments

#10 2007-06-28 15:36:17

Re: Ghost Comments

#11 2007-06-28 15:39:57

Re: Ghost Comments

#12 2007-06-28 15:46:20

Re: Ghost Comments

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