Files
patroni/tests/test_slots.py
T
Alexander KukushkinandGitHub c687838074 Fix race condition with logical slot advance and copy (#3098)
The `SlotsAdvanceThread` is asynchronously calling
pg_replication_slot_advance() and providing feedback about logical
replication slots that must be reinitialized by copying from the
primary. That is, the parent thread will learn about slots to be copied
only when scheduling the next pg_replication_slot_advance() call.
As a result it was possible situation when logical slot was copied with
PostgreSQL restart more than once.

To improve it we implement following measures:
1. do not schedule slot sync if it is in the list to be copied
2. remove to be copued slots from the `self._scheduled` structure
3. clean state of `SlotsAdvanceThread` when slot files are copied.
2024-07-10 17:40:17 +02:00

305 lines
17 KiB
Python

import os
import unittest
from threading import Thread
from unittest import mock
from unittest.mock import Mock, PropertyMock, patch
from patroni import global_config, psycopg
from patroni.dcs import Cluster, ClusterConfig, Member, Status, SyncState
from patroni.postgresql import Postgresql
from patroni.postgresql.misc import fsync_dir
from patroni.postgresql.slots import SlotsAdvanceThread, SlotsHandler
from patroni.tags import Tags
from . import BaseTestPostgresql, psycopg_connect, MockCursor
class TestTags(Tags):
@property
def tags(self):
return {}
@patch('subprocess.call', Mock(return_value=0))
@patch('patroni.psycopg.connect', psycopg_connect)
@patch.object(Thread, 'start', Mock())
@patch.object(Postgresql, 'is_running', Mock(return_value=True))
class TestSlotsHandler(BaseTestPostgresql):
@patch('subprocess.call', Mock(return_value=0))
@patch('os.rename', Mock())
@patch('patroni.postgresql.CallbackExecutor', Mock())
@patch.object(Postgresql, 'get_major_version', Mock(return_value=130000))
@patch.object(Postgresql, 'is_running', Mock(return_value=True))
def setUp(self):
super(TestSlotsHandler, self).setUp()
self.s = self.p.slots_handler
self.p.start()
config = ClusterConfig(1, {'slots': {'ls': {'database': 'a', 'plugin': 'b'}, 'ls2': None}}, 1)
self.cluster = Cluster(True, config, self.leader, Status(0, {'ls': 12345, 'ls2': 12345}),
[self.me, self.other, self.leadermem], None, SyncState.empty(), None, None)
global_config.update(self.cluster)
self.tags = TestTags()
def test_sync_replication_slots(self):
config = ClusterConfig(1, {'slots': {'test_3': {'database': 'a', 'plugin': 'b'},
'A': 0, 'ls': 0, 'b': {'type': 'logical', 'plugin': '1'}},
'ignore_slots': [{'name': 'blabla'}]}, 1)
cluster = Cluster(True, config, self.leader, Status(0, {'test_3': 10}),
[self.me, self.other, self.leadermem], None, SyncState.empty(), None, None)
global_config.update(cluster)
with mock.patch('patroni.postgresql.Postgresql._query', Mock(side_effect=psycopg.OperationalError)):
self.s.sync_replication_slots(cluster, self.tags)
self.p.set_role('standby_leader')
with patch.object(SlotsHandler, 'drop_replication_slot', Mock(return_value=(True, False))), \
patch.object(global_config.__class__, 'is_standby_cluster', PropertyMock(return_value=True)), \
patch('patroni.postgresql.slots.logger.debug') as mock_debug:
self.s.sync_replication_slots(cluster, self.tags)
mock_debug.assert_called_once()
self.p.set_role('replica')
with patch.object(Postgresql, 'is_primary', Mock(return_value=False)), \
patch.object(global_config.__class__, 'is_paused', PropertyMock(return_value=True)), \
patch.object(SlotsHandler, 'drop_replication_slot') as mock_drop:
config.data['slots'].pop('ls')
self.s.sync_replication_slots(cluster, self.tags)
mock_drop.assert_not_called()
self.p.set_role('primary')
with mock.patch('patroni.postgresql.Postgresql.role', new_callable=PropertyMock(return_value='replica')):
self.s.sync_replication_slots(cluster, self.tags)
with patch('patroni.dcs.logger.error', new_callable=Mock()) as errorlog_mock:
alias1 = Member(0, 'test-3', 28, {'conn_url': 'postgres://replicator:[email protected]:5436/postgres'})
alias2 = Member(0, 'test.3', 28, {'conn_url': 'postgres://replicator:[email protected]:5436/postgres'})
cluster.members.extend([alias1, alias2])
self.s.sync_replication_slots(cluster, self.tags)
self.assertEqual(errorlog_mock.call_count, 5)
ca = errorlog_mock.call_args_list[0][0][1]
self.assertTrue("test-3" in ca, "non matching {0}".format(ca))
self.assertTrue("test.3" in ca, "non matching {0}".format(ca))
with patch.object(Postgresql, 'major_version', PropertyMock(return_value=90618)):
self.s.sync_replication_slots(cluster, self.tags)
self.p.set_role('replica')
self.s.sync_replication_slots(cluster, self.tags)
def test_cascading_replica_sync_replication_slots(self):
"""Test sync with a cascading replica so physical slots are present on a replica."""
config = ClusterConfig(1, {'slots': {'ls': {'database': 'a', 'plugin': 'b'}}}, 1)
cascading_replica = Member(0, 'test-2', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'replicatefrom': 'postgresql0'}
})
cluster = Cluster(True, config, self.leader, Status(0, {'ls': 10}),
[self.me, self.other, self.leadermem, cascading_replica], None, SyncState.empty(), None, None)
self.p.set_role('replica')
with patch.object(Postgresql, '_query') as mock_query, \
patch.object(Postgresql, 'is_primary', Mock(return_value=False)):
mock_query.return_value = [('ls', 'logical', 104, 'b', 'a', 5, 12345, 105)]
ret = self.s.sync_replication_slots(cluster, self.tags)
self.assertEqual(ret, [])
def test_process_permanent_slots(self):
config = ClusterConfig(1, {'slots': {'ls': {'database': 'a', 'plugin': 'b'}, 'blabla': {'type': 'physical'}},
'ignore_slots': [{'name': 'blabla'}]}, 1)
cluster = Cluster(True, config, self.leader, Status.empty(), [self.me, self.other, self.leadermem],
None, SyncState.empty(), None, None)
global_config.update(cluster)
self.s.sync_replication_slots(cluster, self.tags)
with patch.object(Postgresql, '_query') as mock_query:
self.p.reset_cluster_info_state(None)
mock_query.return_value = [(
1, 0, 0, 0, 0, 0, 0, 0, 0, None, None,
[{"slot_name": "ls", "type": "logical", "datoid": 5, "plugin": "b",
"confirmed_flush_lsn": 12345, "catalog_xmin": 105, "restart_lsn": 12344},
{"slot_name": "blabla", "type": "physical", "datoid": None, "plugin": None,
"confirmed_flush_lsn": None, "catalog_xmin": 105, "restart_lsn": 12344}])]
self.assertEqual(self.p.slots(), {'ls': 12345, 'blabla': 12344})
self.p.reset_cluster_info_state(None)
mock_query.return_value = [(
1, 0, 0, 0, 0, 0, 0, 0, 0, None, None,
[{"slot_name": "ls", "type": "logical", "datoid": 6, "plugin": "b",
"confirmed_flush_lsn": 12345, "catalog_xmin": 105}])]
self.assertEqual(self.p.slots(), {})
def test_nostream_slot_processing(self):
config = ClusterConfig(
1, {'slots': {'foo': {'type': 'logical', 'database': 'a', 'plugin': 'b'}, 'bar': {'type': 'physical'}}}, 1)
nostream_node = Member(0, 'test-2', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'nostream': 'True'}
})
cascade_node = Member(0, 'test-3', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'replicatefrom': 'test-2'}
})
stream_node = Member(0, 'test-4', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres'})
cluster = Cluster(
True, config, self.leader, Status.empty(),
[self.leadermem, nostream_node, cascade_node, stream_node], None, SyncState.empty(), None, None)
global_config.update(cluster)
# sanity for primary
self.p.name = self.leadermem.name
self.assertEqual(
cluster._get_permanent_slots(self.p, self.leadermem, 'primary'),
{'foo': {'type': 'logical', 'database': 'a', 'plugin': 'b'}, 'bar': {'type': 'physical'}})
self.assertEqual(
cluster._get_members_slots(self.p.name, 'primary'),
{'test_4': {'type': 'physical'}})
# nostream node must not have slot on primary
self.p.name = nostream_node.name
# permanent logical slots are not allowed on nostream node
self.assertEqual(
cluster._get_permanent_slots(self.p, nostream_node, 'replica'),
{'bar': {'type': 'physical'}})
self.assertEqual(
cluster.get_slot_name_on_primary(self.p.name, nostream_node),
None)
# check cascade member-slot existence on nostream node
self.assertEqual(
cluster._get_members_slots(nostream_node.name, 'replica'),
{'test_3': {'type': 'physical'}})
# cascade also does not entitled to have logical slot on itself ...
self.p.name = cascade_node.name
self.assertEqual(
cluster._get_permanent_slots(self.p, cascade_node, 'replica'),
{'bar': {'type': 'physical'}})
# ... and member-slot on primary
self.assertEqual(
cluster.get_slot_name_on_primary(self.p.name, cascade_node),
None)
# simple replica must have every permanent slot ...
self.p.name = stream_node.name
self.assertEqual(
cluster._get_permanent_slots(self.p, stream_node, 'replica'),
{'foo': {'type': 'logical', 'database': 'a', 'plugin': 'b'}, 'bar': {'type': 'physical'}})
# ... and member-slot on primary
self.assertEqual(
cluster.get_slot_name_on_primary(self.p.name, stream_node),
'test_4')
def test_get_slot_name_on_primary(self):
node1 = Member(0, 'node1', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'replicatefrom': 'node2'}
})
node2 = Member(0, 'node2', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'replicatefrom': 'node1'}
})
cluster = Cluster(True, None, self.leader, Status.empty(), [self.leadermem, node1, node2],
None, SyncState.empty(), None, None)
self.assertIsNone(cluster.get_slot_name_on_primary('node1', node1))
def test_should_enforce_hot_standby_feedback(self):
node1 = Member(0, 'postgresql0', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'replicatefrom': 'postgresql1'}
})
node2 = Member(0, 'postgresql1', 28, {
'state': 'running', 'conn_url': 'postgres://replicator:[email protected]:5436/postgres',
'tags': {'replicatefrom': 'postgresql0'}
})
cluster = Cluster(True, None, self.leader, Status.empty(), [self.leadermem, node1, node2],
None, SyncState.empty(), None, None)
self.assertFalse(cluster.should_enforce_hot_standby_feedback(self.p, node1))
@patch.object(Postgresql, 'is_primary', Mock(return_value=False))
def test__ensure_logical_slots_replica(self):
self.p.set_role('replica')
self.cluster.slots['ls'] = 12346
with patch.object(SlotsHandler, 'check_logical_slots_readiness', Mock(return_value=False)):
self.assertEqual(self.s.sync_replication_slots(self.cluster, self.tags), [])
with patch.object(SlotsHandler, '_query', Mock(return_value=[('ls', 'logical', 499, 'b', 'a', 5, 100, 500)])), \
patch.object(MockCursor, 'execute', Mock(side_effect=psycopg.OperationalError)), \
patch.object(SlotsAdvanceThread, 'schedule', Mock(return_value=(True, ['ls']))), \
patch.object(psycopg.OperationalError, 'diag') as mock_diag:
type(mock_diag).sqlstate = PropertyMock(return_value='58P01')
self.assertEqual(self.s.sync_replication_slots(self.cluster, self.tags), ['ls'])
self.cluster.slots['ls'] = 'a'
self.assertEqual(self.s.sync_replication_slots(self.cluster, self.tags), [])
self.cluster.config.data['slots']['ls']['database'] = 'b'
self.cluster.slots['ls'] = '500'
with patch.object(MockCursor, 'rowcount', PropertyMock(return_value=1), create=True):
self.assertEqual(self.s.sync_replication_slots(self.cluster, self.tags), ['ls'])
def test_copy_logical_slots(self):
self.cluster.config.data['slots']['ls']['database'] = 'b'
self.s.copy_logical_slots(self.cluster, self.tags, ['ls'])
with patch.object(MockCursor, 'execute', Mock(side_effect=psycopg.OperationalError)):
self.s.copy_logical_slots(self.cluster, self.tags, ['foo'])
with patch.object(Cluster, 'leader', PropertyMock(return_value=None)):
self.s.copy_logical_slots(self.cluster, self.tags, ['foo'])
@patch.object(Postgresql, 'stop', Mock(return_value=True))
@patch.object(Postgresql, 'start', Mock(return_value=True))
@patch.object(Postgresql, 'is_primary', Mock(return_value=False))
def test_check_logical_slots_readiness(self):
self.s.copy_logical_slots(self.cluster, self.tags, ['ls'])
with patch.object(MockCursor, '__iter__', Mock(return_value=iter([('postgresql0', None)]))), \
patch.object(MockCursor, 'fetchall', Mock(side_effect=Exception)):
self.assertFalse(self.s.check_logical_slots_readiness(self.cluster, self.tags))
with patch.object(MockCursor, '__iter__', Mock(return_value=iter([('postgresql0', None)]))), \
patch.object(MockCursor, 'fetchall', Mock(return_value=[(False,)])):
self.assertFalse(self.s.check_logical_slots_readiness(self.cluster, self.tags))
with patch.object(MockCursor, '__iter__', Mock(return_value=iter([('ls', 100)]))):
self.s.check_logical_slots_readiness(self.cluster, self.tags)
@patch.object(Postgresql, 'stop', Mock(return_value=True))
@patch.object(Postgresql, 'start', Mock(return_value=True))
@patch.object(Postgresql, 'is_primary', Mock(return_value=False))
def test_on_promote(self):
self.s.schedule_advance_slots({'foo': {'bar': 100}})
self.s.copy_logical_slots(self.cluster, self.tags, ['ls'])
self.s.on_promote()
@unittest.skipIf(os.name == 'nt', "Windows not supported")
@patch('os.open', Mock())
@patch('os.close', Mock())
@patch('os.fsync', Mock(side_effect=OSError))
def test_fsync_dir(self):
self.assertRaises(OSError, fsync_dir, 'foo')
def test_slots_advance_thread(self):
with patch.object(MockCursor, 'execute', Mock(side_effect=psycopg.OperationalError)), \
patch.object(psycopg.OperationalError, 'diag') as mock_diag:
for err in ('58P01', '55000'):
type(mock_diag).sqlstate = PropertyMock(return_value=err)
self.s.schedule_advance_slots({'foo': {'bar': 100}})
self.s._advance.sync_slots()
self.assertEqual(self.s._advance._copy_slots, ["bar"])
# we don't want to make attempts to advance slots that are to be copied
self.s.schedule_advance_slots({'foo': {'bar': 101}})
self.assertEqual(self.s._advance._scheduled, {})
self.s._advance.clean()
with patch.object(SlotsAdvanceThread, 'sync_slots', Mock(side_effect=Exception)):
self.s._advance._condition.wait = Mock()
self.assertRaises(Exception, self.s._advance.run)
with patch.object(SlotsHandler, 'get_local_connection_cursor', Mock(side_effect=Exception)):
self.s.schedule_advance_slots({'foo': {'bar': 100}})
self.s._advance.sync_slots()
@patch.object(Postgresql, 'is_primary', Mock(return_value=False))
def test_advance_physical_slots(self):
config = ClusterConfig(1, {'slots': {'blabla': {'type': 'physical'}, 'leader': None}}, 1)
cluster = Cluster(True, config, self.leader, Status(0, {'blabla': 12346}),
[self.me, self.other, self.leadermem], None, SyncState.empty(), None, None)
global_config.update(cluster)
self.s.sync_replication_slots(cluster, self.tags)
with patch.object(SlotsHandler, '_query', Mock(side_effect=[[('blabla', 'physical', 12345, None, None, None,
None, None)], Exception])) as mock_query, \
patch('patroni.postgresql.slots.logger.error') as mock_error:
self.s.sync_replication_slots(cluster, self.tags)
self.assertEqual(mock_query.call_args[0],
("SELECT pg_catalog.pg_replication_slot_advance(%s, %s)", "blabla", '0/303A'))
self.assertEqual(mock_error.call_args[0][0],
"Error while advancing replication slot %s to position '%s': %r")