502 Bad Gateway - Using Siteground Server


I installed the Matomo wordpress plugin on sentispec.com some time ago. During initial installation/configuration I got a series of 502 Bad Gateway errors. I was unable to trace the exact cause at the time and, since the error did not reoccur, I simply ignored the problem.

But, today, the problem came back and, with the help of Siteground support services, it looks like we might have narrowed the problem down to a matomo function that’s looking for mysqli:

The cause for the issue was that the site had hit the processes limit of 80 simultaneous processes and there were a significant number of processes identified like these examples below:

9605 u1293-wqoutvsudjf5 grep grep mysqli


21059 u1293-wqoutvsudjf5 grep grep mysqli

These seem to have originated from the following function:

u1293-wqoutvsudjf5@uk10.siteground.eu:~/www/sentispec.com/public_html$ grep -i “grep mysqli” wp-content/plugins/matomo/classes/WpMatomo/Admin/SystemReport.php
switch ( $this->get_phpcli_output( ‘-m | grep mysqli’ ) ) {

Inspection of the public_html shows no sign of mysqli - is this the problem ??

If so, how should I go about rectifying the problem ?

Will removing and re-installing the matomo plugin be the simplest way forward - or will I risk loosing matomo data in the process ??