Same Query extremely slower on MariaDB 10.3.4 than on MariaDB 10.3.2

SELECT * FROM dev_welu_pdm.appadaptive_pdm_domain_model_stammdaten_artikel a LEFT JOIN (SELECT b.artikel, GROUP_CONCAT(c.reference) AS referenz FROM dev_welu_pdm.appadaptive_pdm_domain_model_stammdaten_artikelreference b

INNER JOIN dev_welu_pdm.appadaptive_pdm_domain_model_klassifizierung_reference c ON b.reference = c.persistence_object_identifier GROUP BY b.artikel) AS x on a.persistence_object_identifier = x.artikel

CREATE TABLE `appadaptive_pdm_domain_model_stammdaten_artikel` (

  `persistence_object_identifier` varchar(40) COLLATE utf8_unicode_ci NOT NULL,

  `artikelnr` varchar(255) CHARACTER SET latin1 COLLATE latin1_general_cs NOT NULL,

  `bezeichnung` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `produkt` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `bonus` tinyint(1) NOT NULL,

  `warengruppe` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `supplychain` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `status` int(11) NOT NULL,

  `mindestbestellmenge` int(11) NOT NULL,

  `verpackungmenge` int(11) NOT NULL,

  `ekmindestbestellmenge` int(11) NOT NULL,

  `laenge` int(11) NOT NULL,

  `breite` int(11) NOT NULL,

  `hoehe` int(11) NOT NULL,

  `bestelllosgroesse` int(11) NOT NULL,

  `gewicht` double NOT NULL,

  `zolltarifnummer` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `gebuehrendsd` double NOT NULL,

  `markenanonym` tinyint(1) NOT NULL,

  `altartikelnr` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `mengeneinheit` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `durchmesser` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `standardlieferant` int(11) NOT NULL,

  `varkey` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `klassegruppe` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `branding` int(11) NOT NULL,

  `verpackung` int(11) NOT NULL,

  `zeichnungsnummer` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `eigenschaften` longtext COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)',

  `verwendungen` longtext COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)',

  `mkategorieen` longtext COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)',

  `gdimandant` int(11) NOT NULL,

  `statustype` int(11) NOT NULL,

  `statushistory` longtext COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)',

  `imagelink` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `qc` tinyint(1) NOT NULL,

  `qp` tinyint(1) NOT NULL,

  `artikelart` int(11) NOT NULL,

  `gdiwgr` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `gdiselektion` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `isoa2` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `gdilazo` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `gdikzhsl` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `bulkprocessflag` int(11) NOT NULL,

  `verwendung` int(11) NOT NULL,

  `verkauflosgroesse` int(11) NOT NULL,

  `lieferzeit` int(11) NOT NULL,

  `pmchecked` tinyint(1) NOT NULL,

  `isstandard` tinyint(1) NOT NULL,

  `referenz` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  `kzal` tinyint(1) NOT NULL,

  `kzsperre` tinyint(1) NOT NULL,

  PRIMARY KEY (`persistence_object_identifier`),

  UNIQUE KEY `UNIQ_307622BC79EBCBC` (`artikelnr`),

  KEY `altArtikelNr` (`altartikelnr`),

  CONSTRAINT `FK_9D3C6D1D21E3D446` FOREIGN KEY (`persistence_object_identifier`) REFERENCES `appadaptive_pdm_domain_model_stammdaten_abstractstammdatum` (`persistence_object_identifier`) ON DELETE CASCADE

) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

CREATE TABLE `appadaptive_pdm_domain_model_stammdaten_artikelreference` (

  `persistence_object_identifier` varchar(40) COLLATE utf8_unicode_ci NOT NULL,

  `artikel` varchar(40) COLLATE utf8_unicode_ci DEFAULT NULL,

  `reference` varchar(40) COLLATE utf8_unicode_ci DEFAULT NULL,

  PRIMARY KEY (`persistence_object_identifier`),

  KEY `IDX_3062FD0DA4375C33` (`artikel`),

  KEY `IDX_3062FD0DAEA34913` (`reference`),

  CONSTRAINT `FK_FDC375A6A4375C33` FOREIGN KEY (`artikel`) REFERENCES `appadaptive_pdm_domain_model_stammdaten_artikel` (`persistence_object_identifier`),

  CONSTRAINT `FK_FDC375A6AEA34913` FOREIGN KEY (`reference`) REFERENCES `appadaptive_pdm_domain_model_klassifizierung_reference` (`persistence_object_identifier`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

CREATE TABLE `appadaptive_pdm_domain_model_klassifizierung_reference` (

  `persistence_object_identifier` varchar(40) COLLATE utf8_unicode_ci NOT NULL,

  `reference` int(11) NOT NULL,

  `bezeichnung` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,

  PRIMARY KEY (`persistence_object_identifier`),

  KEY `bezeichnung` (`bezeichnung`),

  KEY `UNIQ_586EC305AEA34913` (`reference`) USING BTREE,

  CONSTRAINT `FK_A17A64547A46B0A` FOREIGN KEY (`persistence_object_identifier`) REFERENCES `appadaptive_pdm_domain_model_stammdaten_abstractstammdatum` (`persistence_object_identifier`) ON DELETE CASCADE

) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

# Example MariaDB config file for very large systems.

#

# This is for a large system with memory of 1G-2G where the system runs mainly

# MariaDB.

#

# MariaDB programs look for option files in a set of

# locations which depend on the deployment platform.

# You can copy this option file to one of those

# locations. For information about these locations, do:

# 'my_print_defaults --help' and see what is printed under

# Default options are read from the following files in the given order:

# More information at: http://dev.mysql.com/doc/mysql/en/option-files.html

#

# In this file, you can use all long options that a program supports.

# If you want to know which options a program supports, run the program

# with the "--help" option.

# The following options will be passed to all MySQL clients

[client]

#password	= your_password

port		= 3306

socket		= /tmp/mysql.sock

# Here follows entries for some specific programs

# The MySQL server

[mysqld]

port		= 3306

socket		= /tmp/mysql.sock

#skip-external-locking

#thread_stack = 128K

#table_cache = 8192

#tmp_table_size = 320M

max_heap_table_size = 320M

#query_cache_type = 1

query_cache_limit = 64M

#query_cache_min_res_unit = 2k

query_cache_size = 64M

#key_buffer_size = 384M

max_allowed_packet = 1M

#table_open_cache = 512

#sort_buffer_size = 2M

#read_buffer_size = 2M

#read_rnd_buffer_size = 8M

#myisam_sort_buffer_size = 64M

#thread_handling = pool-of-threads

#thread_cache_size = 8

# Try number of CPU's*2 for thread_concurrency

#thread_pool_size = 8

#thread_pool_priority = auto

# Point the following paths to a dedicated disk

#tmpdir		= /tmp/

# Skip reverse DNS lookup of clients

skip-name-resolve

# Don't listen on a TCP/IP port at all. This can be a security enhancement,

# if all processes that need to connect to mysqld run on the same host.

# All interaction with mysqld must be made via Unix sockets or named pipes.

# Note that using this option without enabling named pipes on Windows

# (via the "enable-named-pipe" option) will render mysqld useless!

# 

#skip-networking

# Replication Master Server (default)

# binary logging is required for replication

# log-bin=mysql-bin

# required unique id between 1 and 2^32 - 1

# defaults to 1 if master-host is not set

# but will not function as a master if omitted

server-id	= 1

# Replication Slave (comment out master section to use this)

#

# To configure this host as a replication slave, you can choose between

# two methods :

#

# 1) Use the CHANGE MASTER TO command (fully described in our manual) -

#    the syntax is:

#

#    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,

#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;

#

#    where you replace <host>, <user>, <password> by quoted strings and

#    <port> by the master's port number (3306 by default).

#

#    Example:

#

#    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,

#    MASTER_USER='joe', MASTER_PASSWORD='secret';

#

# OR

#

# 2) Set the variables below. However, in case you choose this method, then

#    start replication for the first time (even unsuccessfully, for example

#    if you mistyped the password in master-password and the slave fails to

#    connect), the slave will create a master.info file, and any later

#    change in this file to the variables' values below will be ignored and

#    overridden by the content of the master.info file, unless you shutdown

#    the slave server, delete master.info and restart the slaver server.

#    For that reason, you may want to leave the lines below untouched

#    (commented) and instead use CHANGE MASTER TO (see above)

#

# required unique id between 2 and 2^32 - 1

# (and different from the master)

# defaults to 2 if master-host is set

# but will not function as a slave if omitted

#server-id       = 2

#

# The replication master for this slave - required

#master-host     =   <hostname>

#

# The username the slave will use for authentication when connecting

# to the master - required

#master-user     =   <username>

#

# The password the slave will authenticate with when connecting to

# the master - required

#master-password =   <password>

#

# The port the master is listening on.

# optional - defaults to 3306

#master-port     =  <port>

#

# binary logging - not required for slaves, but recommended

#log-bin=mysql-bin

#

# binary logging format - mixed recommended 

#binlog_format=mixed

# Uncomment the following if you are using InnoDB tables

#innodb_force_recovery = 0

innodb_data_home_dir = /usr/local/var/mysql/

#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend

innodb_file_per_table

innodb_log_group_home_dir = /usr/local/var/mysql

# You can set .._buffer_pool_size up to 50 - 80 %

# of RAM but beware of setting memory usage too high

innodb_buffer_pool_size = 5G

# innodb_additional_mem_pool_size = 20M

# Set .._log_file_size to 25 % of buffer pool size

innodb_log_file_size = 2500M

innodb_log_buffer_size = 8M

#innodb_flush_log_at_trx_commit = 1

#innodb_lock_wait_timeout = 50

#innodb_large_prefix = 1

[mysqldump]

quick

max_allowed_packet = 16M

[mysql]

no-auto-rehash

# Remove the next comment character if you are not familiar with SQL

#safe-updates

[myisamchk]

#key_buffer_size = 256M

#sort_buffer_size = 256M

#read_buffer = 2M

#write_buffer = 2M

[mysqlhotcopy]

interactive-timeout

#

# These groups are read by MariaDB server.

# Use it for options that only the server (but not clients) should see

#

# See the examples of server my.cnf files in /usr/share/mysql/

#

[client]

#password	= your_password

port		= 3306

socket		= /databases/mysql/mysql.sock

# this is read by the standalone daemon and embedded servers

[server]

# this is only for the mysqld standalone daemon

[mysqld]

#

# * Galera-related settings

#

[galera]

# Mandatory settings

#wsrep_on=ON

#wsrep_provider=

#wsrep_cluster_address=

#binlog_format=row

#default_storage_engine=InnoDB

#innodb_autoinc_lock_mode=2

#

# Allow server to accept connections on all interfaces.

#

#bind-address=0.0.0.0

#

# Optional setting

#wsrep_slave_threads=1

#innodb_flush_log_at_trx_commit=0

# this is only for embedded server

[embedded]

# This group is only read by MariaDB servers, not by MySQL.

# If you use the same .cnf file for MySQL and MariaDB,

# you can put MariaDB-only options here

[mariadb]

port		= 3306

socket		= /databases/mysql/mysql.sock

datadir 	= /databases/mysql

#skip-external-locking

#thread_stack = 128K

#table_cache = 8192

#tmp_table_size = 320M

max_heap_table_size = 320M

#query_cache_type = 1

query_cache_limit = 64M

query_cache_min_res_unit = 2k

query_cache_size = 64M

#key_buffer_size = 384M

max_allowed_packet = 1M

#table_open_cache = 512

#sort_buffer_size = 2M

#read_buffer_size = 2M

#read_rnd_buffer_size = 8M

#myisam_sort_buffer_size = 64M

#thread_handling = pool-of-threads

#thread_cache_size = 8

# Try number of CPU's*2 for thread_concurrency

#thread_pool_size = 4

#thread_pool_priority = auto

# Point the following paths to a dedicated disk

#tmpdir		= /tmp/

# Skip reverse DNS lookup of clients

skip-name-resolve

# Don't listen on a TCP/IP port at all. This can be a security enhancement,

# if all processes that need to connect to mysqld run on the same host.

# All interaction with mysqld must be made via Unix sockets or named pipes.

# Note that using this option without enabling named pipes on Windows

# (via the "enable-named-pipe" option) will render mysqld useless!

# 

#skip-networking

# Replication Master Server (default)

# binary logging is required for replication

# log-bin=mysql-bin

# required unique id between 1 and 2^32 - 1

# defaults to 1 if master-host is not set

# but will not function as a master if omitted

server-id	= 1

# Replication Slave (comment out master section to use this)

#

# To configure this host as a replication slave, you can choose between

# two methods :

#

# 1) Use the CHANGE MASTER TO command (fully described in our manual) -

#    the syntax is:

#

#    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,

#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;

#

#    where you replace <host>, <user>, <password> by quoted strings and

#    <port> by the master's port number (3306 by default).

#

#    Example:

#

#    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,

#    MASTER_USER='joe', MASTER_PASSWORD='secret';

#

# OR

#

# 2) Set the variables below. However, in case you choose this method, then

#    start replication for the first time (even unsuccessfully, for example

#    if you mistyped the password in master-password and the slave fails to

#    connect), the slave will create a master.info file, and any later

#    change in this file to the variables' values below will be ignored and

#    overridden by the content of the master.info file, unless you shutdown

#    the slave server, delete master.info and restart the slaver server.

#    For that reason, you may want to leave the lines below untouched

#    (commented) and instead use CHANGE MASTER TO (see above)

#

# required unique id between 2 and 2^32 - 1

# (and different from the master)

# defaults to 2 if master-host is set

# but will not function as a slave if omitted

#server-id       = 2

#

# The replication master for this slave - required

#master-host     =   <hostname>

#

# The username the slave will use for authentication when connecting

# to the master - required

#master-user     =   <username>

#

# The password the slave will authenticate with when connecting to

# the master - required

#master-password =   <password>

#

# The port the master is listening on.

# optional - defaults to 3306

#master-port     =  <port>

#

# binary logging - not required for slaves, but recommended

#log-bin=mysql-bin

#

# binary logging format - mixed recommended 

#binlog_format=mixed

# Uncomment the following if you are using InnoDB tables

#innodb_force_recovery = 0

innodb_data_home_dir = /databases/mysql/

#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend

innodb_file_per_table

innodb_log_group_home_dir = /databases/mysql

# You can set .._buffer_pool_size up to 50 - 80 %

# of RAM but beware of setting memory usage too high

innodb_buffer_pool_size = 32G

# innodb_additional_mem_pool_size = 20M

# Set .._log_file_size to 25 % of buffer pool size

innodb_log_file_size = 8G

innodb_log_buffer_size = 8M

#innodb_flush_log_at_trx_commit = 1

#innodb_lock_wait_timeout = 50

#innodb_large_prefix = 1

[mysql]

no-auto-rehash

# This group is only read by MariaDB-10.1 servers.

# If you use the same .cnf file for MariaDB of different versions,

# use this group for options that older servers don't understand

[mariadb-10.1]