From nelgin on IRC:

$ admin/setup-amqp-triggers install
setup-amqp-triggers: cannot install: file 'admin/.setup-amqp-triggers-sql' exists
Either setup-amqp-triggers is already running or stopped before its time.
Remove this file if you are sure the script is not still running:
    rm -frv admin/.setup-amqp-triggers-sql
musicbrainz@musicbrainz:~/musicbrainz-docker$ rm -frv admin/.setup-amqp-triggers-sql
removed 'admin/.setup-amqp-triggers-sql/DropFunctions.sql'
removed 'admin/.setup-amqp-triggers-sql/DropTriggers.sql'
removed 'admin/.setup-amqp-triggers-sql/CreateTriggers.sql'
removed 'admin/.setup-amqp-triggers-sql/CreateExtension.sql'
removed 'admin/.setup-amqp-triggers-sql/CreateFunctions.sql'
removed directory 'admin/.setup-amqp-triggers-sql'
musicbrainz@musicbrainz:~/musicbrainz-docker
$ admin/setup-amqp-triggers install
Installing indexer triggers ...
BEGIN
CREATE FUNCTION

[...]

CREATE FUNCTION
COMMIT
BEGIN
CREATE TRIGGER

[...]

CREATE TRIGGER
COMMIT
Regenerating SQL scripts in /tmp/indexer-sql/...
Could not find CreateTables.sql, search_path might not be correct
Could not find CreateTables.sql, skipping
Could not find CreateIndexes.sql, skipping
Could not find CreateSearchIndexes.sql, skipping
Could not find CreateReplicationTriggers.sql, skipping
Done.

The script setup-amqp-triggers use 3 generated files:

• CreateTriggers.sql
• CreateExtension.sql
• CreateFunctions.sql

But other files are expected by the script admin/GenerateSQLScripts.pl from musicbrainz-server repository. The issue is that the output of GenerateSQLScritps.pl is misleadingly logging "Could not find..." about these claimed-missing files only rather than logging the success of the 3 expected files.