Steps to reproduce:

1. Upgrade agent2 + plugin from 6.0.17 to 6.0.18

Result:

[PostgreSQL] Connection failed: failed to connect to `host=/var/run/postgresql user=zabbix database=user=zabbix`: server error (FATAL: database "user=zabbix" does not exist (SQLSTATE 3D000)). 

Expected:

No error

Fix:
Downgrade zabbix-agent2-plugin-postgresql to 6.0.17.

Environment:
EL7 x86_64

Official Zabbix Repository for RHEL7.

User-macro-override for the PostgreSQL-user {$PG.USER} }}and for the URI {{{$PG.URI}