Merge branch 'update_1231' into 'dev'

mysql: remove some unused indices and add thr_parent index. pgsql: sync...

See merge request !1560
4 jobs for dev in 8 minutes and 43 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #356526
php7.2_mariadb

00:07:31

passed #356524
php7.2_mysql 1/2

00:07:15

passed #356525
php7.2_mysql 2/2

00:08:12

passed #356527
php7.2_postgres

00:07:52