I am having a database connection error on wordpress.

After a post, the site spins for a long time and gives one liner database connection issue. Sometimes, the site shows wordpress error page "Error establishing a database connection" and wants me to check wp-config.php and states cant contact the database server.

When I check the log. I see...
[error] PHP Fatal error: Call to undefined function wp_cache_get() in /srv/www/example.com/public_html/wp-includes/functions.php on line 346

I checked on line 346

      $notoptions = wp_cache_get( 'notoptions', 'options' );

from line 344 to 350

   if ( ! defined( 'WP_INSTALLING' ) ) {
      // prevent non-existent options from triggering multiple queries
      $notoptions = wp_cache_get( 'notoptions', 'options' );
      if ( isset( $notoptions[$option] ) )
         return $default;

      $alloptions = wp_load_alloptions();

I have
mysql 5.1.41
wordpress 3.2.1
apache

for cache I have w3tc

???

I am on lamp set up.

thank you.

I followed a few of the threads, and seemed to solve the issue

these links should help anyone that has the same issue
http://library.linode.com/troubleshooti ... networking
http://library.linode.com/lamp-guides/u ... 0.04-lucid

The second link is broken

http://library.linode.com/lamp-guides/u ... 0.04-lucid

This is most likely because 10.04 isn't supported at all by Canonical at this point. If you're using Ubuntu 10.04 I'd really recommend upgrading to a more recent version of Ubuntu to avoid running into complications.

If you're actually running a more recent version, these guides should be applicable:

https://www.linode.com/docs/websites/la ... e-pangolin

https://www.linode.com/docs/websites/la ... untu-14-04

If you're not running Ubuntu at all, we have guides for CentOS 6/7, Debian 7/8 and Arch Linux as well:

https://www.linode.com/docs/websites/lamp/

Hope this helps!

It's a 4.5 year old post...