Cannot redeclare class QueryCache ... on line 16

I have just upgraded from 1.5.1 to 1.5.3. Everything went well I thought, but after the database upgrade I am getting blanks pages on my website and admin page. I checked the logs and this is what I'm getting.

PHP Fatal error: Cannot redeclare class QueryCache in /home/xxxxxx/public_html/includes/classes/query_cache.php on line 16

When I check line 16 of query_cache.php this is whats on it.

class QueryCache {

I thought I would try to upgrade the database again, but when I run zc_install all I get now is install button no upgrade. My site is https://www.countryhomemade.com

Thanks,
Randy

You've got leftover files from having installed the old query-cache addon, including in the /includes/auto_loaders and /includes/init_includes folders.
Part of upgrading is removing files that no longer belong.

See same discussion here: http://www.zen-cart.com/showthread.php?200507&p=1252800#post1252800

rtfulk:

... Cannot redeclare class QueryCache in /home/xxxxxx/public_html/includes/classes/query_cache.php ...
Typically indicates some leftover files from a previous install. Can you try the following:

1. Log into your Zen Cart administrative interface.
2. Select "Tools" -> "Developers Tool Kit" from the top menu.
3. Scroll down to "lookup in all files".
4. Enter "QueryCache" for the "Key or Name:".
5. Leave "All Files Look-ups:" set to "All Files - Catalog/Admin".
6. Leave "File type:" set to ".php only".
7. Click the search button to the right.
   This should help locate where the leftover file causing the QueryCache to be loaded twice is located.

Did you know you can search the Zen Cart site using a search engine by using keywords and adding site:zen-cart.com to your search? I personally find this method of searching effective.

NOTE: Beaten to the answer by DrByte while typing :)

rtfulk:

I have just upgraded from 1.5.1 to 1.5.3. Everything went well I thought, but after the database upgrade I am getting blanks pages on my website and admin page. I checked the logs and this is what I'm getting.

PHP Fatal error: Cannot redeclare class QueryCache in /home/xxxxxx/public_html/includes/classes/query_cache.php on line 16

I think the database upgrade aspect may be a bit of a red herring. The PHP error is related to the files, not the database.

rtfulk:

When I check line 16 of query_cache.php this is whats on it.

class QueryCache {

This is what I would be expecting to find here (based on the error message).

rtfulk:

I thought I would try to upgrade the database again, but when I run zc_install all I get now is install button no upgrade. My site is www.countryhomemade.com

Step away from the database for the time being.

What the error message is telling us is "Line #16 of query_cache.php needs to create a 'class' called 'QueryCache' but I can't do this because a class of this name has already been created".

In other words, the message itself isn't particularly helpful because it doesn't tell us where the 'class' was previously declared, so that's really the 1st thing you need to find out.

There aren't many possible causes of classes to be redeclared, and probably the most common cause is because a backup file declaring the same class exists in the same folder as the original file. There are other reasons, but the bottom line is, you have somehow got two different files that both contain a line that reads

"class QueryCache {"

So, the easiest way to tackle this problem is to use the ZenCart Developers Toolkit and perform a case sensitive search on all the .php files for "QueryCache".

On a 'good' system (V1.5.3) there will be a total of four matches, in two different files.

**/includes/auto_loaders/config.core.php
**Line #76 : 'className'=>'QueryCache',

and
**/includes/classes/query_cache.php
**Line #13 : * QueryCache
Line #16 : class QueryCache {
Line #18 : function QueryCache() {

If you find any other files that match the 1st thing to do is rename them so they don't have a .php filename extension (especially if they appear to be a backup file). This is all you will probably need to do to take care of the error being reported. If this is the only error on the site you'll probably find it'll just spring back to life. If it doesn't you'll probably find a different error is now being reported.

I would suggest that when you get to this point that you come back here and report on your findings in regards to the possible duplicated/backup file as well as reporting any further error messages. Avoid the temptation to go any further yourself (unless confident with what you are doing), because the last thing we need at this stage is the possibility of compounding the problem.

Cheers
RodG

RodG:

So, the easiest way to tackle this problem is to use the ZenCart Developers Toolkit and perform a ...
I was going to suggest that too ... but then I remembered that they can't access their Admin:
rtfulk:

... I am getting blanks pages on my website and admin page.

DrByte:

I was going to suggest that too ... but then I remembered that they can't access their Admin:

:blush::blush::blush: Oh yeah. That would make this suggestion a little difficult wouldn't it.

Time for bed. Brain ceased to function.

Cheers
RodG

DrByte:

I was going to suggest that too ... but then I remembered that they can't access their Admin:
:blush: Yup, missed this...

Although a bit strange as QueryCache is not typically loaded (out of box) when accessing the Zen Cart administrative interface... Perhaps some files were accidentally uploaded / merged in the wrong locations (catalog versus admin)?

Thanks for all the suggestions, unfortunately I don't have access to the admin area.

DrByte, I took your suggestion and looked at the 2 folders.
/includes/autoloader had 2 files dated back to 1.5.1 config.query_cache.php and nochex_apc.core.php
/includes/init_includes folders had on file dated back to 1.5.1 init_nochex_apc_sessions.php

Instead of deleting them right now I just renamed with a .bak extension. Now on the web page I get this
Sorry!
There seems to be a problem connecting to our database. Please give us a few minutes to remedy the problem. Thank you.
To verify the site status click here.

When I click it nothing happens.

My question is: Am I on the right track and also should there be any files dated back to 1.5.1 version?

rtfulk:

DrByte, I took your suggestion and looked at the 2 folders.
/includes/autoloader had 2 files dated back to 1.5.1 config.query_cache.php and nochex_apc.core.php
/includes/init_includes folders had on file dated back to 1.5.1 init_nochex_apc_sessions.php

Instead of deleting them right now I just renamed with a .bak extension.Good :)
Yes, you're on the right track.

rtfulk:

Now on the web page I get this
Sorry!
There seems to be a problem connecting to our database. Please give us a few minutes to remedy the problem. Thank you.
To verify the site status click here.
That indicates that the db can't be connected. Specifically, when using the credentials in your admin configure.php the database isn't responding.

One other question I noticed the stylesheet.css and stylesheet_css_buttons.css were updated. I have my own template folder should I merge those 2 css files to my template css files?

DrByte:

Good :)
Yes, you're on the right track.

That indicates that the db can't be connected. Specifically, when using the credentials in your admin configure.php the database isn't responding.

I have checked and double checked the Database username and password just to make sure everything is correct.

Can this be done? Since the database has been updated to 1.5.3. Can I upload the files from 1.5.3 and copy my configure.php files and my custom template over? I only have a couple of mods installed .

rtfulk:

Can this be done? Since the database has been updated to 1.5.3. Can I upload the files from 1.5.3 and copy my configure.php files and my custom template over? I only have a couple of mods installed .
Yes, and that's essentially what I usually do when upgrading anyway ... my process is described here: http://www.zen-cart.com/entry.php?3-How-do-I-rebuild-my-site-on-the-new-version-instead-of-upgrading

rtfulk:

One other question I noticed the stylesheet.css and stylesheet_css_buttons.css were updated. I have my own template folder should I merge those 2 css files to my template css files?

You can certainly compare those files with the same files from the prior version (WinMerge is handy for this) and then make the corresponding updates in your own template.
In fact, that's what upgrading is about.

Thanks for all the help. I have reverted back to 1.5.1 for now. I have ran into one issue The admin area loads now, but the webpage is still blank. Any suggestions?

I have setup a test site and database for 1.5.3 and it is running just the generic Zen Cart stuff right now after I get the site back up I can start working on incorporating my live site into it.

Thanks,
Randy

"webpage blank" means that you've got a debug-log file in your /logs folder. Since it's an admin-related log (the characters -adm- will appear in the filename), make sure to obfuscate your admin-folder's name if/when you post its contents.

The latest error in the log files for admin was from 3 days ago (before I started the upgrade). I was a ZEND error php was changed to 5.4 and should have been 5.2. That has been corrected.

With the database being updated to 1.5.3 and I'm running 1.5.1 that should be an issue should it?

rtfulk:

With the database being updated to 1.5.3 and I'm running 1.5.1 that should be an issue should it?

It is normally not recommended; however, in the case of running v1.5.1 against a v1.5.3 database, there should be no problem ... with one exception: any customer or administrator passwords that were automatically updated to more secure formats will no longer work if you're using v1.5.1.

Update.

First I want to thank everyone for their suggestions and help. Everything is back up and running. I wish I could be more specific in what I done to get it back up and running, but this is what got my website back up.

I started at the beginning I downloaded a fresh copy of 1.5.1 and started comparing and uploading files in the includes folder after each file I checked the website. I got lucky the auto_loader folder had the problem in it. I don't know which file it was since I uploaded the folder completely.

Even though this is a vague answer, I hope it can help someone else that has encountered the blank page problem.

Thanks,
Randy