Ajax Error 500

Re: Ajax Error 500 - SOLVED!

Fri, 19 Jun 2009 14:41:37 +0000

64 should be OK. If you have some problems (that can appear on very specific pages) you can try if increasing it makes sense.

But sometimes increasing the memory limit means that script will hit the time limit, so probably setting it too high is also not a perfect solution.

Summing up, this all depends on way you use Wikidot.

And yes, upgrading pcre installs the default Debian/Ubuntu version, that uses stack, so you need to recompile it again, to benefit from it.

Re: Ajax Error 500 - SOLVED!

Fri, 19 Jun 2009 14:05:59 +0000

I'm not as embarrassed as I was last night. I just figured out that an update to PCRE reverted the match recursion setting back to using "stack" instead of "heap". I set up a new VM with my rev 393 ISO and found that after applying a bunch of Ubuntu updates (including pcre) that the setting got switched back.

I had previously increased my memory limits a while ago due to a similar error. I blogged about it here. I just increased it to 64M, 4x the default of 16M - I was totally making a guess! ;) Do you think I should crank it up to 200m - 300m as you suggest? Is there any chance of a performance hit if I set it too high?

-Ed

Re: Ajax Error 500 - SOLVED!

Fri, 19 Jun 2009 09:44:51 +0000

So, memory limit didn't have to be raised?

Don't be ashamed, I'm really glad, that this works for you, and we know EXACTLY what is the problem. And the solution is put on wiki page for anyone encountering the same problem in future.

Thanks Ed.

Re: Ajax Error 500 - SOLVED!

Fri, 19 Jun 2009 04:16:14 +0000

OK, now I'm embarrassed. After trying all of your suggestions with no success I decided to double-check my PCRE config (even though I was sure it was correct - NOT!) It did turn out to be a problem with my PCRE config:

root@mywikidot:/usr/src/debian/pcre/pcre3-7.4# pcretest -C | grep 'Match recursion' Match recursion uses stack

Redoing the steps in the PCRE tweaks article gave the correct result and my pages are saving fine now.

root@mywikidot:/usr/src/debian/pcre/pcre3-7.4# pcretest -C | grep 'Match recursion' Match recursion uses heap

The funny thing is that I was extremely careful in documenting my steps to insure that I had a bullet-proof install. I obviously had some kind of error or missed step when I did the PCRE stuff. Thanks for helping me sort it out.

I'm going to do some more testing with rev 466 and then create an updated installable ISO.

-Ed

Re: Ajax Error 500

Thu, 18 Jun 2009 22:41:05 +0000

Unfortunately this can mean almost anything, it's like:

some PHP error appear (probably with PCRE or other library)
therefor PHP dies with no output (Wikidot echoes the content all at once at the end of processing)
the bug is so critical that even no Fatal Error: message appears
the fcgi connection breaks (because backend actually dies)
Lighttpd logs the situation

I have one more idea. Raise memory limit in php.ini (to like 200-300 MB to be sure). I bet this solves the problem (that, I still believe, is connected to regular expressions or some process during compiling page).

You can share what amount of memory you ended with.

Re: Ajax Error 500

Thu, 18 Jun 2009 22:28:44 +0000

Hmmm… I already had PCRE installed - your instructions are exactly the same as those from Michal's early guide and the instructions i copied to my giude. After removing the comments from the 2 lines in php.ini, I still get the same error. BTW, I'm testing this on my VM with rev 466 (which otherwise seems very stable).

I think this is the error generated (from /var/log/lighttpd/error.log)

2009-06-18 17:20:06: (mod_fastcgi.c.2471) unexpected end-of-file (perhaps the fastcgi process died): pid: 6353 socket: unix:/var/run/lighttpd/php-fastcgi.socket-3

2009-06-18 17:20:06: (mod_fastcgi.c.3281) response not received, request sent: 58618 on socket: unix:/var/run/lighttpd/php-fastcgi.socket-3 for /ajax-module-connector.php , closing connection

Does this shed any more light? Anything else I can try?

Thanks for all your help!

-Ed

edit: This is the source of one of the pages I'm trying to save:

-- show code --

Re: Ajax Error 500

Thu, 18 Jun 2009 21:22:53 +0000

Oh, yeah, this seems like pcre regular expression library tweaks.

Check PCRE tweaks

Ajax Error 500

Thu, 11 Jun 2009 05:15:05 +0000

I just ran into an issue with my server at work when trying to save a page with a pretty large "complex" table ([[table]]…[[row]]..[[cell]]…[[/cell]]…[[/row]]…[[/table]]). If I reduce the size of the table, I can eventually get the page to save.

It seems like the the parser can't handle that amount of "wiki syntax" at once. I have pages with a lot more characters, but not as much wiki markup.

On the Pro site a similar error was reported and fixed (http://pro.wikidot.com/ticket:241)

Can you share what the fix was so I can try it on my server?

Thanks,
Ed