fix: fixed Slave Replication Lag metric to exclude master server from calculation

Author: cuprumtan

mamonsu/plugins/pgsql/driver/pool.py

@@ -17,7 +17,7 @@ class Pool(object):
         ),
         "replication_lag_slave_query": (
             """
-            SELECT CASE WHEN coalesce(pg_last_{1}(), '0/00000000') = coalesce(pg_last_{2}(), '0/00000000')
+            SELECT CASE WHEN NOT pg_is_in_recovery() OR coalesce(pg_last_{1}(), '0/00000000') = coalesce(pg_last_{2}(), '0/00000000')
                         THEN 0
                         ELSE extract (epoch FROM now() - coalesce(pg_last_xact_replay_timestamp(), now() - INTERVAL '{0} seconds'))
                    END;

mamonsu/plugins/pgsql/xlog.py

@@ -23,7 +23,7 @@ class Xlog(Plugin):
     """
     # get time of replication lag
     query_agent_replication_lag = """
-    SELECT CASE WHEN coalesce(pg_last_{1}(), '0/00000000') = coalesce(pg_last_{2}(), '0/00000000')
+    SELECT CASE WHEN NOT pg_is_in_recovery() OR coalesce(pg_last_{1}(), '0/00000000') = coalesce(pg_last_{2}(), '0/00000000')
                 THEN 0
                 ELSE extract (epoch FROM now() - coalesce(pg_last_xact_replay_timestamp(), now() - INTERVAL '{0} seconds'))
             END;

mamonsu/tools/bootstrap/sql.py

@@ -49,7 +49,7 @@
 CREATE OR REPLACE FUNCTION mamonsu.timestamp_get()
 RETURNS double precision AS $$
   SELECT
-      CASE WHEN pg_last_{11}() = pg_last_{12}() THEN 0
+      CASE WHEN NOT pg_is_in_recovery() OR pg_last_{11}() = pg_last_{12}() THEN 0
       ELSE extract (epoch FROM now() - coalesce(pg_last_xact_replay_timestamp(), to_timestamp(ts)))
       END
   FROM mamonsu.timestamp_master_{1}