This error means that the MySQL/MariaDB server is not able to process the request. You will see in the error_log files entries like:
[21-Feb-2020 21:34:00 UTC] PHP Warning: Error while sending QUERY packet. PID=4697 in /home/flighting/public_html/wp-includes/wp-db.php on line 2030
[21-Feb-2020 21:34:00 UTC] PHP Warning: Error while sending QUERY packet. PID=4726 in /home/flighting/public_html/wp-includes/wp-db.php on line 2030
[21-Feb-2020 21:34:00 UTC] PHP Warning: Error while sending QUERY packet. PID=4734 in /home/flighting/public_html/wp-includes/wp-db.php on line 2030
[21-Feb-2020 21:34:19 UTC] PHP Warning: Error while sending QUERY packet. PID=4734 in /home/flighting/public_html/wp-includes/wp-db.php on line 2030
[21-Feb-2020 21:34:19 UTC] PHP Warning: Error while sending QUERY packet. PID=4726 in /home/flighting/public_html/wp-includes/wp-db.php on line 2030
[21-Feb-2020 21:34:19 UTC] PHP Warning: Error while sending QUERY packet. PID=4697 in /home/flighting/public_html/wp-includes/wp-db.php on line 2030
This issue can happen during a site/server attack. Because of the huge number of requests, at some point, the SQL server might be killed, or it can produce errors.
Another cause can be the server configuration. Some hosts limit the maximum number of database requests in a specific time interval.
In any case, it’s a server thing, and you should ask your host about the warnings.
A server admin should check the database – if there are any tables that need to be repaired. You can check our article on how to optimize MySQL/MariaDB tables.