Error 2013 (HY000): Lost connection to MySQL server during query

I had my 10.2.15-MariaDB server crashed after a select count(*) from a 18.6 Gb table. It's not a HeidiSQL error because it also happens if i do it using MariaDB's command prompt.

After this crash, i can't do a select count(*) over a couple of seconds that i get the same error again.

It doesn't seem like a configuration issue as this weren't happening before the first crash. I used to run several hours querys without a problem.

My interactive_timeout variable is set to 28800:

"Variable_name";"Value" "connect_timeout";"36000" "delayed_insert_timeout";"300" "innodb_flush_log_at_timeout";"1" "innodb_lock_wait_timeout";"50" "innodb_rollback_on_timeout";"OFF" "interactive_timeout";"28800" "lock_wait_timeout";"86400" "net_read_timeout";"30" "net_write_timeout";"60" "slave_net_timeout";"60" "thread_pool_idle_timeout";"60" "wait_timeout";"28800"

I know this is not a HeidiSQL problem, but you help me?

Thanks!

Oh, i forgot to say that i still have 62 Gb. free in my hard drive. My PC has 32 Gb. of RAM memory.

In order to be precise, my timeout happens after approximately 2 minutes.