Title: Constant 500 Server Errors
Last modified: August 31, 2016

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# Constant 500 Server Errors

 *  [gbbgadmin](https://wordpress.org/support/users/gbbgadmin/)
 * (@gbbgadmin)
 * [10 years, 4 months ago](https://wordpress.org/support/topic/constant-500-server-errors/)
 * I can’t seem to make this plugin work, and I can’t seem to find any similar support
   issues/discussions. In addition, it seems this particular plugin gets very little
   replies when people have problems, so I am shooting in the dark and hoping for
   something…
 * I have a configuration like this:
    1. Load balancer using tcp balancing 2. 3 
   application servers (ubuntu 14.04, php7.0-fpm, etc.) 3. 1 Master Percona(MySQL
   5.6) 4. 1 Slave Percona(MySQL 5.6)
 * Slave server is configured to replicate from master, and it is working perfectly
   as expected.
 * My load balancer works perfectly to balance traffic among the 3 app servers. 
   All three app servers can connect to the database servers without issue. I have
   manually tested via terminal from all three app servers.
 * App servers have a Read/Write user that can connect to the Master DB server. 
   App servers have a Read-Only user that can connect to the Slave DB server.
 * I have WordPress 4.4.1 running on the app servers using Gluster and the site 
   is working perfectly, as long as I only connect with the Master DB. It is when
   I try to add HyperDB and distribute reads/writes to their appropriate DB that
   problems arise.
 * My wp-config defines the master DB host and slave DB host. It also defines the
   users and their respective passwords. I have tried the following scenarios:
 * 1. Use only 1 username/pw combo for both db servers with full privileges
    2. 
   Use 2 username/pw combos for each server (which i truly want because readonly
   has read only access to the particular db)
 * I have tried configuring the hosts using their hostname (properly set in /etc/
   hosts on all servers and tested multiple times to ensure no networking issues).
 * I have tried configuring the hosts using their private IP addresses, and even
   port 3306, just in case that was an issue.
 * I have tried even using only the master db server as both the read/write and 
   the read-only server. I have tried using the slave db server as the read/write
   and read-only server (making sure to restore all db back to sync with master 
   so we are not out of sync or having corrupt tables).
 * Here is my experience:
 * 1. When I run the WordPress site using normal setup (standard config and only
   1 db connection) everything works perfectly. Can browse the site, can edit/save
   pages and posts, can install, delete plugins, etc. Everything works 100% as expected.
   Whether I connect to the Master or Slave DB server.
 * 2. When I add db.php to the /wp-content folder to activate HyperDB, I get 2 outcomes:
   
   a. Either I can see the static homepage with out-of-date information, but when
   I try to access /wp-admin I get 500 server error b. I get 500 server error on
   all pages
 * I have tried to define the hosts in db-config.php with many settings. Currently
   it is:
 * $wpdb->add_database(array(
    ‘host’ => ‘xxx.xxx.xxx.xx’, ‘user’ => ‘user’, ‘password’
   => ‘password’, ‘name’ => ‘db-name’, ‘write’ => 1, ‘read’ => 1,
 * ));
 * $wpdb->add_database(array(
    ‘host’ => ‘xxx.xxx.xxx.xx’, ‘user’ => ‘user’, ‘password’
   => ‘password’, ‘name’ => ‘db-name’, ‘write’ => 0, ‘read’ => 1, ));
 * *note – I have omitted the ip addresses, username, pw, and db-name to protect
   the security of our system. They are correctly in the file. At present trying
   to hard-code them to db-config to override wp-config. I have also tried setting
   them as variables and then defining them in wp-config.
 * No matter what I do, how much I check connections, networking, wp-config, db-
   config, caching setting, etc. NOTHING WORKS. All I get is 500 server errors from
   HyperDB.
 * Any ideas?
 * [https://wordpress.org/plugins/hyperdb/](https://wordpress.org/plugins/hyperdb/)

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Thread Starter [gbbgadmin](https://wordpress.org/support/users/gbbgadmin/)
 * (@gbbgadmin)
 * [10 years, 4 months ago](https://wordpress.org/support/topic/constant-500-server-errors/#post-6993799)
 * After nearly 24 hours working on this issue, I am beginning to think there are
   serious problems between HyperDB and WordPress 4.4.1 version. I am going to downgrade
   to WordPress 4.3.2 version (latest that says HyperDB works with on the plugin
   page) and see what happens. Will post results here. If it works on 4.3.2 we will
   know it is a WordPress version incompatibility issue.
 *  [kodedigital](https://wordpress.org/support/users/kodedigital/)
 * (@kodedigital)
 * [10 years, 4 months ago](https://wordpress.org/support/topic/constant-500-server-errors/#post-6994076)
 * We were looking into a similar issue and it’s actually down to a few things but
   mainly the fact you like us are trying to use PHP7 and that mysql-connect ([http://php.net/manual/en/function.mysql-connect.php](http://php.net/manual/en/function.mysql-connect.php))
   is no longer part of it.
 * HyperDb as it stands is written to use mysql-connect not mysqli-connect so you
   will get the 500 error and due to a bunch of error suppression no actual error.
 * We are currently evaluating this fork with mysqli support to see if it suits 
   our purposes.
    [https://github.com/soulseekah/hyperdb-mysqli](https://github.com/soulseekah/hyperdb-mysqli)
 *  Thread Starter [gbbgadmin](https://wordpress.org/support/users/gbbgadmin/)
 * (@gbbgadmin)
 * [10 years, 1 month ago](https://wordpress.org/support/topic/constant-500-server-errors/#post-6994121)
 * We have solved this issue by reverting our entire infrastructure back to MySQL
   5.6 (not Percona) and rolling back to PHP-FPM V. 5.6. Now HyperDB works as expected.
   So, apparently you are correct. The issue is in PHP 7.0 or versions above 5.6
   as we can see in our testing.

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘Constant 500 Server Errors’ is closed to new replies.

 * ![](https://s.w.org/plugins/geopattern-icon/hyperdb_33353d.svg)
 * [HyperDB](https://wordpress.org/plugins/hyperdb/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/hyperdb/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/hyperdb/)
 * [Active Topics](https://wordpress.org/support/plugin/hyperdb/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/hyperdb/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/hyperdb/reviews/)

 * 3 replies
 * 2 participants
 * Last reply from: [gbbgadmin](https://wordpress.org/support/users/gbbgadmin/)
 * Last activity: [10 years, 1 month ago](https://wordpress.org/support/topic/constant-500-server-errors/#post-6994121)
 * Status: not resolved