Test DROP TRIGGER in a Galera cluster

The docker-compose.yml file describes three containers – db00, db01 and db02 – based on bitnami/mariadb-galera, each running MariaDB 10.5.5 with Galera 4.5 and linked into a single multi-master cluster.

The script run_test.sh starts the cluster via docker-compose, waits for all three servers to be operational and then executes three scripts:

1. test0.sql – executed on db02 – initialises two databeses with one table each. Then it adds a trigger to one of the tables, which inserts a value into the other table (i.e. writes a log), whenever the first table receives a new row (after insert). To test the trigger, three random values are added to this table. Finally the trigger is dropped.
2. test1.sql – executed on db01 - simply adds further two values to the table, which has had the trigger.
3. We count – and echo – on db00 the number of logged items.

The trigger has been dropped after three inserts, so the echoed number should be 3, but the drop trigger on db02 is not propagated by Galera, so the insert on db01 still runs the trigger, resulting in 5 log entries.