I am experiencing strange database-related behaviours on my server that hosts a few versions of the same website.

The problem relates to making content and theme updates to one of the subdomain sites and somehow they are appearing on the main domain's WordPress.

The main website is domain.ca and the other two can be found at staging.domain.ca and beta.domain.ca.

Each site has its own database with a shared wordpressuser for managing them. Each database is set to use the default wp_ prefix. The database names are unique and should not conflict with each other.

I have also tested with a completely unique user, but the same issues occur.

I have replaced the Authentication Unique Keys and Salts on all three sites, so they are unique to each one.

Each site has its own defined URLs in their respective wp-config.php files.

define( 'WP_HOME', 'https://domain.ca' );
define( 'WP_SITEURL', 'https://domain.ca' );

define( 'WP_HOME', 'https://staging.domains.ca' );
define( 'WP_SITEURL', 'https://staging.domain.ca' );

define( 'WP_HOME', 'https://beta.domains.ca' );
define( 'WP_SITEURL', 'https://beta.domain.ca' );

I have used similar setups on other WordPress-based websites with no issues.

Can anyone shed some insight on why this could be occurring?


  • Just because you didn’t mention it explicitly, but are your wp-config.php files each properly pointing to separate databases? Dec 5, 2023 at 1:01
  • @JacobPeattie Yes, each wp-config.php file has its own unique DB_NAME set. Dec 5, 2023 at 1:17
  • 1
    Can you be more specific about the things you are seeing modified? Examples? And are you using some kind of caching plugin?
    – vancoder
    Dec 5, 2023 at 20:20
  • @vancoder All three sites have the Salmon theme installed. When I have edited slideshow items, the text and images change on the subdomains and/or parent domain. The only caching is the Redis Object Cache plugin and what Nginx offers outside of WordPress. Dec 5, 2023 at 21:07

1 Answer 1


I have resolved my issues by reviewing the Redis Cache plugin installation guide and making the following changes inside the wp-config.php files on each WordPress installation.

The define( 'WP_REDIS_PREFIX', '' ); was added with the values set as production, staging, and beta for each respective site.

The define( 'WP_REDIS_DATABASE', 0 ); values for the staging and beta sites were change to 1 and 2 respectively.

After making these changes, the cache data collision issues were resolved and there was no longer any data being overwritten between the websites.

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