Content of Loomio disappeared after update - Migration command execution freezes

Hello everybody, I currently made a pull from master branch and relaunched the docker-compose.

I did the following steps as described in the help documentation:

docker-compose pull
docker-compose down
docker-compose run app rake db:migrate
docker-compose up -d

I tried to redo the procedure and I noticed, that after the command

docker-compose run app rake db:migrate

the log seems to freeze. I waited at least 20 Minutes and nothing seemed to proceed.

Here is the log until the line where it stops doing anything - any ideas? Can someone help?

gmt@bogus:~/loomio-deploy$ docker-compose run app rake db:migrate

Creating loomio-redis ... done

Creating loomio-db    ... done

Redis#exists(key) will return an Integer by default in redis-rb 4.3. The option to explicitly disable this behaviour via Redis.existsreturnsinteger will be removed in 5.0. You should use exists? instead.

Migrating to CreateEventsDescendantCount (20200815201352)

== 20200815201352 CreateEventsDescendantCount: migrating ======================

-- addcolumn(:events, :descendantcount, :integer, {:default=>0, :null=>false})

   -> 2.6092s

-- execute("UPDATE events\n             SET descendantcount = (\n               SELECT count(id) from events children\n               WHERE children.discussionid = events.eventableid\n             )\n             WHERE events.kind = 'newdiscussion'")

   -> 0.0541s

-- execute("UPDATE events\n         SET descendantcount = (\n           SELECT count(children.id)\n           FROM events children\n           WHERE\n              children.discussionid = events.discussionid AND\n              children.id != events.id AND\n              children.positionkey like CONCAT(events.positionkey, '%')\n          )\n         WHERE discussionid is not null and id > 0 and id <= 10000")