MariaDB my.cnf

[client-server]
port                            = 3306
socket                          = /run/mysqld/mysqld.sock

[client]

[mysqld]
user                            = mysql
pid-file                        = /run/mysqld/mysqld.pid
basedir                         = /usr
datadir                         = /var/lib/mysql
tmpdir                          = /tmp
lc_messages_dir                 = /usr/share/mysql
lc_messages                     = en_US
skip-external-locking
skip-name-resolve
performance_schema
bind-address                    = 127.0.0.1
character-set-server            = utf8mb4
collation-server                = utf8mb4_general_ci

# Main
max_connections                 = 250 # change if many connections errors
connect_timeout                 = 5
wait_timeout                    = 600
max_allowed_packet              = 64M
thread_cache_size               = 250 # same as max_connections
key_buffer_size                 = 2048M # 1Gb=128M 2Gb=256M 4Gb=512M 8Gb=1024M 16Gb=2048M 32Gb=4096M
join_buffer_size                = 4M
sort_buffer_size                = 4M
bulk_insert_buffer_size         = 16M
tmp_table_size                  = 2048M # 1Gb=128M 2Gb=256M 4Gb=512M 8Gb=1024M 16Gb=2048M 32Gb=4096M
max_heap_table_size             = 2048M # 1Gb=128M 2Gb=256M 4Gb=512M 8Gb=1024M 16Gb=2048M 32Gb=4096M
table_open_cache                = 4096
table_definition_cache          = 800

# Query Cache
query_cache_type                = 1
query_cache_limit               = 2M
query_cache_size                = 32M

# Logging
log_warnings                    = 2
slow_query_log_file             = /var/log/mysql/mariadb-slow.log
long_query_time                 = 3
log_slow_verbosity              = query_plan
#log_bin                        = /var/log/mysql/mariadb-bin
#log_bin_index                  = /var/log/mysql/mariadb-bin.index
#expire_logs_days               = 10
#max_binlog_size                = 100M
#general_log
#general_log_file                = /var/log/mysql/mysql_query.log
#log_error                       = /var/log/mysql/mysql_error.log

# InnoDB
default_storage_engine          = InnoDB
innodb_log_file_size            = 96M # 1Gb=16M 2Gb=64M >=4Gb=96M (25% from innodb_buffer_pool_size)
innodb_buffer_pool_size         = 768M # 1Gb=128M 2Gb=512M >=4Gb=768M 
innodb_log_buffer_size          = 8M
innodb_file_per_table           = 1
innodb_open_files               = 400
innodb_io_capacity              = 400
innodb_flush_method             = O_DIRECT
innodb_flush_log_at_trx_commit  = 2
innodb_buffer_pool_instances    = 1

[mysqld_safe]
nice = 0
skip_log_error
syslog

[mysqldump]
quick
quote-names
max_allowed_packet              = 64M

[isamchk]
key_buffer                      = 16M

!includedir /etc/mysql/conf.d/