As Tom J Nowell pointed out in the comments, this is a very specific situation, which makes the question rather difficult to answer. If the source system has suitable code for pushing data to other systems, then you could consider registering a custom REST endpoint at the WordPress end. The endpoint would receive, validate and … Read more
As discussed in comments, the problem was a missing prce2 package which meant preg_match(), used by $wpdb->db_version() to parse the MySQL version number out of SELECT VERSION(), didn’t work. Solved by sudo yum install pcre2
How connection pooling can be implemented in WordPress?
Slow search queries with a large database
Does WordPress work with MySQL active-active GTID-Based Replication without any issues?
MySQL has died. How do I recover? SOLVED
SELECT option_name, option_value FROM wp_options WHERE autoload = ‘yes’ always is running
Admin backend is very slow to create or edit posts by core meta query
WordPress cannot detect (present, loaded) mysqli
So the issue was actually a DDOS attack on our site. I used urlsnarf to see what requests were being placed and there were basically hundreds of POST request from about 20-30 or so IP addresses. Seems quite small scale for what I understood is a typical DDOS attack. It also explains why it took … Read more