MySQL: How can I reduce the number of mysqld processes?

Question

linux

Hello. Debian Jessie has MariaDB version 10.1.19 installed. Running htop noticed that there are many mysqld processes running:

/etc/mysql/my.cnf

[mysql]
port                                = 3306
socket                              = /var/run/mysqld/mysqld.sock

[mysqld]
user                                = mysql
default-storage-engine              = InnoDB
socket                              = /var/run/mysqld/mysqld.sock
pid-file                            = /var/run/mysqld/mysqld.pid
bind-address                        = 127.0.0.1
long-query-time                     = 5
low-priority-updates

# Safety #
max-allowed-packet                  = 16M
max-connect-errors                  = 1000000
skip-name-resolve
skip-external-locking
sql-mode                            = STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ENGINE_SUBSTITUTION,NO_ZERO_DATE,NO_ZERO_IN_DATE
sysdate-is-now                      = 1
innodb                              = FORCE
transaction-isolation               = READ-COMMITTED

# Data storage #
basedir                             = /usr
datadir                             = /var/lib/mysql
tmpdir                              = /tmp

# Caches and limits #
tmp-table-size                      = 32M
max-heap-table-size                 = 32M
query-cache-type                    = 1
query-cache-size                    = 1M
query-cache-limit                   = 128K
query-cache-min-res-unit            = 4096
query-cache-strip-comments          = 1
max-connections                     = 9
thread-cache-size                   = 50
open-files-limit                    = 65535
table-definition-cache              = 4096
table-open-cache                    = 4096

# MyISAM #
key-buffer-size                     = 128K
myisam-recover                      = FORCE,BACKUP

# InnoDB #
innodb-flush-method                 = O_DIRECT_NO_FSYNC
innodb-log-files-in-group           = 2
innodb-log-file-size                = 16M
innodb-flush-log-at-trx-commit      = 0
innodb-file-per-table               = 1
innodb-file-format                  = Barracuda
innodb-buffer-pool-size             = 64M
innodb-buffer-pool-instances        = 1
innodb-buffer-pool-dump-at-shutdown = 1
innodb-buffer-pool-load-at-startup  = 1

# Logging #
#log-error                           = /var/log/mysql/mariadb-errors.log
log-queries-not-using-indexes       = 0
slow-query-log                      = 0
slow-query-log-file                 = /var/log/mysql/mariadb-slow.log

!includedir /etc/mysql/conf.d/

How can I reduce the number of mysqld processes? To run a minimum of processes with the possibility of increasing them if necessary.

Answer 1

These are not processes, but threads.
Don't dig there, don't touch.