MySQL

Problem:

# mysqldump --user=mydbuser --password=mypassword --tab=backup/db mydbname
mysqldump: Got error: 1: "Can't create/write to file '/www/backup/db/yourls_log.txt' (Errcode: 13 "Permission denied")" when executing 'SELECT INTO OUTFILE'

Command(s):

Create DB Table:

Problem (Drupal Status Report) "/admin/reports/status":

Transaction isolation level
REPEATABLE-READ
The recommended level for Drupal is "READ COMMITTED". 
See the setting MySQL transaction isolation level page for more information.

Solution (in sites/default/settings.php):

Give DB User File permission:

mysqldump --user=MyDBUser --password --tab=/tmp/my_export_dir MyDBName

In /etc/mysql/mariadb.conf.d/50-server.cnf

[mysqld]

#my custom changes
innodb_buffer_pool_size = 8G
query_cache_size=256M

Problem:

drush sql-cli
drush sql:cli

select * from table1;
truncate table2;

Mysql Group Concat & Order By Rand()

Watch MySQL full-processlist every 0.5 seconds :

while : ; do mysql -u MY_USERNAME --password='MY_PASSWORD' -e "show full processlist"; sleep 0.5; done