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Internal server errors

Posted: Mon Jan 29, 2007 6:54 pm
by KB
Hi,

I know a few users have reported problems accessing the forums on occasions. I have had the same issue myself - you get a blank page telling you have experienced an "Internal server error". I'm sorry if you have been having problems. I finally contacted my domain hosts today and this is the live chat we had:

- ME: Hi, I have been having problems with my PHPBB forum (self-installed on my Aplus website) where I am getting a lot of server errors. This seems to be at times of high traffic and nothing to do with the PHPBB installation. Are there any known issues here? I am wondering if it is my bandwidth. Thanks...
- HOST: there are certain limitations on running php scripts on our shared hosting
- HOST: that will create intermittent 500 internal server error
- HOST: s
- ME: That is exactly what is happening. What can I do about it?
- HOST: * no more than 4 simultaneous PHP processes per user.
- HOST: * 30 seconds maximum execution time for each PHP process.
- HOST: you can search google for ways to optimise the phpbb forum
- HOST: so it cant have more than 4 simultaneous processes
- HOST: started
- ME: Will do - thanks.
- HOST: thats most probably whats causing you the problems , the 30 seconds are probably enough


So, now I know the problem - uh, except I haven't got a clue what he's talking about, and it was one of those situations (like when you walk into a record shop - think High Fidelity) where you feel like you've got to bluff it out. "Oh yeah, of course - simultaneous PHP processes and 30 seconds max execution time - like, duh, shoulda know that, right?"

If anybody has a clue how to fix this, or knows of any PHPBB sites or hint pages that can help, please do let me know...

Best,
Keith

Posted: Tue Jan 30, 2007 2:10 am
by janra
only 4 simultaneous connections? That's awfully low :-(

Posted: Tue Jan 30, 2007 2:58 am
by janra
I did a quick google around to see if I could spot anything, but I couldn't find anything that I recognized as potentially useful. Since I don't know phpBB at all, I'm afraid I couldn't refine my search at all. From what I was able to glean from the pages I visited, phpBB either doesn't have a configuration file, or doesn't want people to touch it.

At any rate, I *can* try to translate what they said :-)

The simultaneous connections and execution time are actually related. Every time a visitor loads a page, that's a connection, and it takes a certain amount of time to gather the posts, format them, and send them to the visitor. The host has a maximum on this execution time - if something is taking longer than 30 seconds to send, you may have a problem (such as an endless loop) and cutting it off is a reasonable response. As the host said, that isn't likely to be your problem.

If a second visitor loads a page before the first one has finished, you now have a simultaneous connection. Apparently your host has limited you to four simultaneous connections, and that is the problem - so you have to somehow tell phpBB that it is also limited so it can fail a little more gracefully. (That, unfortunately, I don't know how to do.)

Posted: Tue Jan 30, 2007 5:15 pm
by kastorff
I run a small discussion board. The 4 connection limit does seem very restrictive based on my prior experience with shared hosting. These forums aren't that busy (relatively speaking), and if we're seeing issues with this level of loading, it's only gonna get worse...eventually resulting in the forums being unusable. I'd suggest looking for a new hosting provider.

Posted: Tue Jan 30, 2007 6:34 pm
by AmberV
I think that connexions are even compounded in some cases. In response mode, I have had the reply interface load, but the quick reference comment area below fails. Since the reply portion must have a database connexion for part of its content (message notification, login status, and breadcrumb trail), that must mean that whenever a user clicks reply, two connexions are registered where one can fail independently from the other.

Posted: Wed Jan 31, 2007 4:16 am
by janra
Good point Amber - I've clicked post, got an ISE, then found out the comment actually did post, despite the ISE.

Posted: Wed Jan 31, 2007 5:11 pm
by KB
Eek. Thanks for the info. This doesn't sound brilliant. My hosts are brilliant in nearly every other way, too... Cheap with great service and numerous features. Oh well, guess I'll have to look into this when my contract runs out with them in August again...
Thanks again,
Keith

one idea..

Posted: Thu Feb 15, 2007 3:50 pm
by daveyc
i used to run a phpbb forum and one thing that i used to do to improve performance was manually dump the cache table via phpmyadmin or the host interface...might remedy a few issues, not sure...

there's some amazing support on the phpbb forums as well, certainly worth a look.

Posted: Tue Jul 17, 2007 8:59 pm
by Timotheus
I continue to get frequent "Internal Server Errors", when visiting this forum. especially around ten or eleven o'clock in the evening. It looks like ten or at most fifteen simultaneous visitors are the absolute maximum the server and / or the host can handle. And especially late in the evening the simultaneous visitors frequently are more than fifteen.

Posted: Wed Jul 18, 2007 4:10 pm
by Khadrelt
I asked around on another phpBB forum I visit at projectmagma.net, and the answer I got was this:

I'd recommend just switching web hosting companies - a max of 4 simultaneous php processes is a ridiculously low number. That means if your friend had ANY other php scripts (say a photo gallery, or a wiki, or wordpress, or ANYTHING) running ANYWHERE on his site that would reduce the number of people who could get on to the forums at once. Likewise, if 4 ppl are on the forum at the same time no other php script can be run on the entire script.


So yeah, another confirmation that the basic problem is the whole 4 processes thing, as others have said.

Posted: Wed Jul 18, 2007 6:00 pm
by alexwein
Timotheus wrote:I continue to get frequent "Internal Server Errors", when visiting this forum. especially around ten or eleven o'clock in the evening. It looks like ten or at most fifteen simultaneous visitors are the absolute maximum the server and / or the host can handle. And especially late in the evening the simultaneous visitors frequently are more than fifteen.


I get these all the time, even when I'm the only one on the site. I've written Keith (as have others, most likely) and he is aware of the issue. It can be so bad I give up entirely and just check back later.

Posted: Wed Jul 18, 2007 8:22 pm
by Clea
Okay, I'm not sure how relevant this is but while the four processes sounds like an awfully low number I think half of that statement has somehow been lost. What the original reply said was:

- HOST: * no more than 4 simultaneous PHP processes per user.


So, if you are happy with your host in every other way, you may want to look into that more carefully before panicking... just a thought.

Posted: Thu Jul 19, 2007 3:18 am
by janra
Clea wrote:Okay, I'm not sure how relevant this is but while the four processes sounds like an awfully low number I think half of that statement has somehow been lost. What the original reply said was:

- HOST: * no more than 4 simultaneous PHP processes per user.


So, if you are happy with your host in every other way, you may want to look into that more carefully before panicking... just a thought.


I suspect that "per user" is from the host's point of view, i.e., KB is one user, and his website gets 4 connections. Host-side restrictions are usually set up that way.

Posted: Thu Jul 19, 2007 7:32 am
by Timotheus
But coudn't it be simply a capacity problem of the server?

Posted: Thu Jul 19, 2007 12:39 pm
by AmberV
Indeed. In this case, we are considered to be sessions in hosting nomenclature. Not users. Users are the people/person who maintain a web site.