Database Query Failed - Any way to debug without access to apache error log?

Question

Since a week ago I suddenly get the following error on sr.midneid.at/qa

A Question2Answer database query failed when generating this page.
A full description of the failure is available in the web server's error log file.

Is there ANY possiblity to debug this without access to the apache server log as I am on a shared server without any but basic rights. I really hope there is a way to solve this problem without setting up everything step by step and copying questions out of the database over :(

I already tried to delete all plugins from the plugin folder, it did not change anything so I reverted this.

Edit:Based on pupi1985 and steven2's answers I got the queries, they exceed the 8.000 character length limit for a post so I pasted it to pastebin.

http://pastebin.com/a85Gj2JF

Edit2: With the updated help I get the following query as failing. Please note I replaced the real username with "user". The username was correct but I think it is not a good idea to share that information :)

PHP Question2Answer MySQL query error 1142: INSERT command denied to user 'user'@'localhost' for table 'qa_options' - Query: REPLACE qa_options (title, content) VALUES ('flatbox_author', 'Q2A Market')

Comments

What are you getting in your error log??

Answer 1

It is not a good idea to debug this way (and particularly not in a production environment) but considering you seem to have no access to the error logs then probably this might help.

1. Open file qa-include/qa-db.php

2. Locate this line: https://github.com/q2a/question2answer/blob/9a4ffead73bc07da3a9d980c7875c7a3653b0471/qa-include/qa-db.php#L176

3. Replace it with:

echo 'Question2Answer MySQL query: '.$query;

Awful, but it is still better than nothing :)

Edit: The previous approach would show you all the queries run and, at the end, the one to blame. Considering the one to blame based on your output is a query that seems to be right then I assume your output is not complete for some reason. Then you could follow this approach to output only the failing query with some extra information about it:

0. Undo all previous step changes

1. Open file qa-include/qa-db.php

2. Locate this line: https://github.com/q2a/question2answer/blob/9a4ffead73bc07da3a9d980c7875c7a3653b0471/qa-include/qa-db.php#L94

3. Replace in that line @error_log with echo

That will show you any failing queries.

Comments

To expand on a great idea, and make it production:

Don't replace that line, but **above** it add:
if ( $_SERVER['REMOTE_ADDR'] == '123.33.33.55' ) echo 'Question2Answer MySQL query: '.$query;

replace 123.33.33.55 with your own ip.  This way, you can make it production, and only your ip will see the error code'

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Very creative idea. I got the output but it is quite long, so please apologize if this is not helpful. I have added a link to pastebin with the result. If you just have ANY idea or direction you can further point me, I would be very glad.

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Hi Nox, cannot see the link, please provide.

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I've updated my answer with a slightly better approach

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Thank you very much! Now I got a single failing query (I edited the initial answer above) and It makes much more sense.

@sense Forget about the previous link to pastebin, it was not very helpful anyway, but now I only get the failing query posted above.

Please note that I replaced the real database username with "user" but left everything else unchanged.

Edit2: Based on your help I could find out - that for whatever reason my user lost the privileges of insert. I think I will have to contact the webhoster before I can fix anything here. Interestingly, the same user has still all rights in his second database so there definetly is something broken.

Thank you two very much, I will select your answer as solution as soon as I have got a reply from the provider and was able to verify that.

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Thank you for your help. The problem was that the database began to exceed the providers limit and therefore they stripped my user the INSERT rights.