fix: make sure application_name for discovery rule is unique

Author: casperr0

mamonsu/plugins/pgsql/driver/pool.py

@@ -37,7 +37,7 @@ class Pool(object):
             'select size, twice_used, dirty from public.mamonsu_buffer_cache()'
         ),
         'wal_lag_lsn': (
-            "SELECT application_name, " \
+            "SELECT CONCAT(application_name, ' ', pid) as application_name, " \
             " flush_lag, replay_lag, write_lag, " \
             " pg_wal_lsn_diff(pg_current_wal_lsn(), replay_lsn) AS total_lag " \
             " FROM pg_stat_replication;",
@@ -46,7 +46,7 @@ class Pool(object):
             " FROM public.mamonsu_count_wal_lag_lsn()"
         ),
         'xlog_lag_lsn': (
-            "SELECT application_name, " \
+            "SELECT CONCAT(application_name, ' ', pid) as application_name, " \
             "pg_xlog_location_diff(pg_current_xlog_location(), replay_location) AS total_lag  " \
             "FROM pg_stat_replication;",
             "SELECT application_name, total_lag "\

mamonsu/tools/bootstrap/sql.py

@@ -127,7 +127,7 @@
 CREATE OR REPLACE FUNCTION public.mamonsu_count_{3}_lag_lsn()
 RETURNS TABLE(application_name TEXT, {8} total_lag NUMERIC ) AS $$
 SELECT 
-application_name,
+CONCAT(application_name, ' ', pid) as application_name,
 {6}
 pg_{7}_diff(pg_current_{7}(), replay_{9}) AS total_lag 
 FROM pg_stat_replication