I've created the Java Spring Boot app and deployed it on the Tomcat, in the Apache VPS server. The operating system is Linux CentOS 7. My app is working great, but only on Sunday, around 02:00 am UTC + 1 until 12:00 am UTC + 1 pages are loaded extremely slow. Not only pages of my app, but also PHPMyAdmin, and Linux terminal. And only at that time. Last night, slowing started on Sunday at 07:00 am. I don't have much knowledge about this topic, I will be very grateful if you can help me, or at least to guide me in the right direction.
I've first tried to see my MySQL slow log file, I've had a few slow queries but at 7:30 (the employees experienced huge lags at 7:00). Also, the same queries are not slow on any other day, so the problem is probably not because of the queries.
In my Apache error log I've found three types of strange errors (I'll censor the actual addresses):
[Sun Nov 28 07:04:10.585796 2021] [proxy_http:error] [pid 27425] (20014)Internal error: [client (ip address of the client)] AH01102: error reading status line from remote server my server:8080, referer: http://my_server/money_table/money_table
[18:61976] AH00898: Error reading from remote server returned by /money_table/money_table, referer: http://my_server/money_table/money_table
This error happens multiple times for different pages.
In another error log file I've got:
[Sun Nov 28 05:39:07.745375 2021] [autoindex:error] [pid 8543] [client (ip of client)] AH01276: Cannot serve directory /var/www/html/: No matching DirectoryIndex (index.html,index.php) found, and server-generated directory index forbidden by Options directive
[Sun Nov 28 05:42:04.966887 2021] [php7:error] [pid 28141] [client (ip of client)] script '/var/www/html/wp-login.php' not found or unable to stat.
I don't know why it is mentioned wp-login.php because I didn't use WordPress at all.
The hosting provider stated that everything is alright with their services.
Does this have something about the application or about the server? I think that, if the application is wrong, the error will repeat every day not only on Sunday midnight and morning (employees are doing the same job each day).
