The MySQL Error Log Is an Excellent Tool for Debugging a Joomla Website

A couple of days ago a client called us and told us that whenever someone tries to click on a link in an ACYMailing newsletter, he was seeing a blank page. The client assured us that he didn’t change anything in the code.

If you have been reading our blog for a while, then you will probably know that a blank page is a sign of an error, and that in order to see that error, you will need to set the Error Reporting level to “Maximum” in your global configuration settings. And so we did that, but we still didn’t see any error. Easily fixable, we thought! But despite using every imaginable way in our guide to display the errors, we still couldn’t see what the error was.

But then, for some reason, we thought about checking the MySQL error log – maybe it can tell us something. And so we ssh’d to the server and we went to the /var/lib/mysql directory, and we opened the error file (the error file is usually called *.err where * is typically the name of the server, appended to the main domain name on that server; an example of an error’s file name is: ). Here’s what we saw:

150303 9:16:45 [ERROR] /usr/sbin/mysqld: Table ‘./[dbname]/jos_acymailing_userstats’ is marked as crashed and should be repaired

Ah ha! So the problem was with a corrupt table. So, in order to fix the problem, we did the following:

  • We logged in to phpMyAdmin (from the WHM interface).
  • We selected the database serving the Joomla website.

  • We clicked on the SQL tab at the top.

  • We pasted the below SQL query in the textarea:

    REPAIR TABLE `jos_acymailing_userstats`;

  • We clicked on GO at the bottom and we waited for a few minutes until the table was repaired.

  • That fixed the problem!

But, what caused the problem in the first place?

The jos_acymailing_userstats table was a heavily active MyISAM table with substantial number of writes per second. Tables that active (write wise) are vulnerable to crashes if a server hiccup occurs during a write activity (for example, during an INSERT or an UPDATE query). A good idea would be to flip such tables from MyISAM to InnoDB (a performance hit may occur if you do this though; you will need to make some modifications to your my.cnf file if this happens).

As you can see, the MySQL error log was crucial in identifying the problem. So, the next time you see a blank page on your Joomla website, take a glimpse at your MySQL error log and see if you can find anything there. If, however, you feel that this whole thing is a bit over your head, then please contact us. We will be able to fix the problem for you in as little time as possible and for a very, very affordable fee!

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