Drop replication slot after failover being demoted to secondary (#43)

Replication slot record remains in pg_replication_slots after
primary gets demoted to be secondary. This commit explicitly
removes the record upon demotion.

Fixes #42

src/bin/pg_autoctl/fsm_transition.c

@@ -471,6 +471,13 @@ fsm_rewind_or_init(Keeper *keeper)
 		}
 	}
 
+	if (!primary_drop_replication_slot(postgres, config->replication_slot_name))
+	{
+		log_error("Failed to drop replication slot \"%s\" used by the standby failed",
+				  config->replication_slot_name);
+		return false;
+	}
+
 	return true;
 }
 

tests/pgautofailover_utils.py

@@ -483,6 +483,17 @@ def disable(self, feature, formation='default'):
                              name="disable feature",
                              timeout=COMMAND_TIMEOUT)
 
+    def failover(self, formation='default', group=0):
+        """
+        performs manual failover for given formation and group id
+        """
+        failover_commmand_text = "select * from pgautofailover.perform_failover('%s', %s)" %(formation, group)
+        failover_command = [shutil.which('psql'), '-d', self.database, '-c', failover_commmand_text]
+        failover_proc = self.vnode.run(failover_command)
+        wait_or_timeout_proc(failover_proc,
+                         name="manual failover",
+                         timeout=COMMAND_TIMEOUT)
+
 
 
 def wait_or_timeout_proc(proc, name, timeout):

tests/test_basic_operation.py

@@ -2,6 +2,7 @@
 from nose.tools import *
 
 cluster = None
+monitor = None
 node1 = None
 node2 = None
 node3 = None
@@ -14,7 +15,8 @@ def teardown_module():
     cluster.destroy()
 
 def test_000_create_monitor():
-    cluster.create_monitor("/tmp/monitor")
+    global monitor
+    monitor = cluster.create_monitor("/tmp/monitor")
 
 def test_001_init_primary():
     global node1
@@ -97,6 +99,23 @@ def test_014_add_new_secondary():
     assert node3.wait_until_state(target_state="secondary")
     assert node2.wait_until_state(target_state="primary")
 
-def test_015_drop_primary():
+def test_015_multiple_manual_failover_verify_replication_slot_removed():
+    monitor.failover()
+    assert node3.wait_until_state(target_state="primary")
+    assert node2.wait_until_state(target_state="secondary")
+    node2_replication_slots = node2.run_sql_query("select count(*) from pg_replication_slots")
+    assert node2_replication_slots == [(0,)]
+    node3_replication_slots = node3.run_sql_query("select count(*) from pg_replication_slots")
+    assert node3_replication_slots == [(1,)]
+
+    monitor.failover()
+    assert node2.wait_until_state(target_state="primary")
+    assert node3.wait_until_state(target_state="secondary")
+    node2_replication_slots = node2.run_sql_query("select count(*) from pg_replication_slots");
+    assert node2_replication_slots == [(1,)]
+    node3_replication_slots = node3.run_sql_query("select count(*) from pg_replication_slots");
+    assert node3_replication_slots == [(0,)]
+
+def test_016_drop_primary():
     node2.drop()
     assert node3.wait_until_state(target_state="single")