WordPress › Support » [Plugin: DB Cache Reloaded] getting a fatal error

Ovidiu
Member
Posted 2 months ago #

after activation seeing this in my log and the blog goes white:

PHP Fatal Error: cannot redeclare class wpdb in ....../db.php on line 83

http://wordpress.org/extend/plugins/db-cache-reloaded/
sirzooro
Member
Posted 2 months ago #

Do you get this error every time? Or only once, e.g. after activating plugin?
Ovidiu
Member
Posted 2 months ago #

let me rephrase:

I activate the plugin all looks good, but after activating it, the back end and the front end, both display a blank white page.

I then check the error log and see that error every time I tried to acces the blog. I delete the filedb.php and all is good btu the caching then doesn't seem to happen. so I deactivated the plugin again.
sirzooro
Member
Posted 1 month ago #

I have updated plugin, so it detects such situations and displays custom error message in admin section. When you have PHP 5 and Reflection extension loaded, it additionally shows file where wpdb class was previously defined.

Please upgrade to version 1.1.
Ovidiu
Member
Posted 1 month ago #
ok, seems to work now, but in the source code of my site, I always see output like this:
```


```
it always says 0 cached queries so it seems ineffctive on my site :-(

follow the link and check it out: http://pacura.ru
sirzooro
Member
Posted 1 month ago #

Do you have any warning message displayed in admin section? DB Cache Reloaded should display it if it will detect that wpdb class is already loaded.

Which WP version do you use?

Please also check your WP files. On my install (WP 2.8.4) following files are loaded before wp-content/db.php:
index.php
wp-blog-header.php
wp-load.php
wp-config.php
wp-settings.php
wp-includes/compat.php
wp-includes/functions.php
wp-includes/classes.php

or (for admin section):

wp-admin/options-general.php
wp-admin/admin.php
wp-load.php
wp-config.php
wp-settings.php
wp-includes/compat.php
wp-includes/functions.php
wp-includes/classes.php

Please check these files to make sure they are the same as in official WP archive (except for wp-config). If you have changed them (e.g. wp-config), please check your changes.
Ovidiu
Member
Posted 1 month ago #

hey,

what do you mean by admin section? do you mean on your plugins settings page? if so there are no errors or warnings.

I am on 2.8.4 and yes, my wp-config has been modified quite heavily. i.e. for use with the wp-tuner plugin, etc.

shall I post a version without my salts and secrets and passwords onto pastebin?

Oh, and wp-settings I have modified too, for wp-tuner. but those changes should not be a problem...
sirzooro
Member
Posted 1 month ago #

Admin section = admin panel or backend (all pages within wp-admin/ dir).

As I checked, WP Tuner plugin is responsible for this problem. I have notified its author about this issue - hope it will correct it and release new version soon.
Ovidiu
Member
Posted 1 month ago #

great. will wait for the update then. the author of wp-tuner is pretty good at implementing changes, although a little slow to catch up sometimes. :-)

will post again later, after a wp-tuner upgrade or try and disable that plugin for now :-)
datacode
Member
Posted 1 month ago #

I'm getting the error upon activation...
Fatal error: Call to a member function load() on a non-object in /nfs/c12/h12/mnt/12345/domains/dev.thedomain.com/html/wp-content/db.php on line 839

Both the front end and back end error this way. Only way to fix is to remove the db.php file from wp-content manually.

This is on WP 2.8.4 using DB Cache Reloaded 1.1 on a MediaTemple gs site.
sirzooro
Member
Posted 1 month ago #

@datacode: which PHP version do you use?

Please also check if upgrade to version 1.2 will help - I did some change in this version, which may help.
Phoenixheart
Member
Posted 1 month ago #

Hello,
The same happens to me here: http://www.thica.net/ too. It seems DB Cache Reloaded has no effects:



I'm using DreamHost, if that matters.
Phoenixheart
Member
Posted 1 month ago #

Yeah, and the same plugin version works very well on my localhost:


sirzooro
Member
Posted 1 month ago #

@Phoenixheart: I have added some extra code to help diagnose such
problems in last DB Cache Reloaded version - 1.4. It shows -1 as cached query count when there is a conflict with other plugin, and messages in admin backend. Could you check it and let me know if it displays them on your setup?
Phoenixheart
Member
Posted 4 weeks ago #

@sirzooro: Well, seems it was a problem with my hosting company. I switched host and DB Cache Reloaded works like a charm now. Great plugin!
dbasulto
Member
Posted 4 weeks ago #

For me, it crashes apache when enabled :(

I use nginx as a transparent proxy...
sirzooro
Member
Posted 3 weeks ago #

@Phoenixheart: good to hear that. BTW, which version of PHP you were using on DreamHost? I suspect that your problem may be related to PHP4.

@dbasulto: do you run Apache on Windows or Linux/Unix? I had some Apache crashes on my dev machine (Windows XP Pro SP3), but I have not investigated this deeper.
Ovidiu
Member
Posted 3 weeks ago #
my pages are all showing this in the source:
```


```
in the admin dashboard I see: `DB Cache Reloaded Error: wpdb class is redefined, plugin cannot work!
Previous definition is at /var/www/clients/client1/web7/web/wp-includes/wp-db.php:53.andDB Cache Reloaded Error: DB Module (wpdb class) is not loaded. Please open the Options Page, disable caching (remember to save options) and enable it again. If this will not help, please check FAQ how to do manual upgrade.`

following that advice doesn't help...

then I remembered the incompatibility with wp-tuner, disabled taht one e voila: `

`

but now that wp-tuenr doesn't work, how do I check the speed improvement? is hte figure reported by DB cache reloaded: 1.386 seconds without the caching or with the caching?
sirzooro
Member
Posted 3 weeks ago #

@Ovidiu: you can compare numbers displayed in these footer comments with caching enabled and disabled. You posted two such numbers: 1.445 sec without caching (when you had WP Tuner enabled), and 1.386 sec with caching (when you disabled WP Tuner). So there is small improvement, but numbers are still high. Please check if you have some plugin which is written in really inefficient way (try disabling all plugins one by one, or install fresh WP copy on subdomain), or your server is overloaded. You can use DB Cache Reloaded plugin to check page loading time.
Ovidiu
Member
Posted 3 weeks ago #

here are some examples with caching:







and some without caching:




looks pretty random to me. maybe its not the DB calls slowing down the page?

btw. can you also contribute to this thread, maybe? http://wordpress.org/support/topic/320578?replies=3
sirzooro
Member
Posted 3 weeks ago #

In case of such variation of results you need to calculate average. In this case average time for caching enabled is 1.55 sec, and for caching disabled is 1.93 sec.

Also please take a look on this thread.
sdhunt
Member
Posted 3 weeks ago #

sirzooro, I've been using DB Cache Reloaded for several weeks without a problem. It's been great.
Then all of a sudden this morning I found my blog had gone to a blank white page. The admin section was unaffected so I tried disabling DB Cache Reloaded and the site returned. I had not added/updated any plugins or edited the theme.
So, I'm puzzled as to why this is happening. I tried clearing the cache but that didn't help. Now, whenever I enable DB my blog goes blank and whenever I disable it the site loads correctly.

Any thoughts on what I can do about this?
dbasulto
Member
Posted 3 weeks ago #

@sirzooro,

Apache, on CentOS.

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[Plugin: DB Cache Reloaded] getting a fatal error (23 posts)

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