openstack/swift
Code Issues Proposed changes

Sharding: Use the metadata timestamp as last_modified

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This is a follow up patch from the cleaning up cleave context's patch
(patch 681970). Instead of tracking a last_modified timestamp, and storing
it in the context metadata, use the timestamp we use when storing any
metadata.

Reducing duplication is nice, but there's a more significant reason to
do this: affected container DBs can start getting cleaned up as soon as
they're running the new code rather than needing to wait for an
additional reclaim_age.

Change-Id: I2cdbe11f06ffb5574e573c4a60ba4e5d41a00c50
This commit is contained in:
Matthew Oliver 2019-09-21 16:06:24 +10:00 committed by Tim Burke
parent 81a41da542
commit 370ac4cd70
4 changed files with 37 additions and 79 deletions
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10
swift/container/backend.py
View File

@ -1996,20 +1996,24 @@ class ContainerBroker(DatabaseBroker):
self.update_metadata({'X-Container-Sysmeta-Shard-' + key:
(value, Timestamp.now().internal)})
def get_sharding_sysmeta(self, key=None):
def get_sharding_sysmeta(self, key=None, include_timestamps=False):
"""
Returns sharding specific info from the broker's metadata.
:param key: if given the value stored under ``key`` in the sharding
info will be returned.
:param include_timestamps: bool, return the metadata timestamps
along with the metadata. I.e last modified timestamp.
:return: either a dict of sharding info or the value stored under
``key`` in that dict.
"""
prefix = 'X-Container-Sysmeta-Shard-'
metadata = self.metadata
info = dict((k[len(prefix):], v[0]) for
k, v in metadata.items() if k.startswith(prefix))
info = dict((k[len(prefix):], v if include_timestamps else v[0])
for k, v in metadata.items() if k.startswith(prefix))
if key:
if include_timestamps:
return info.get(key, (None, None))
return info.get(key)
return info

21
swift/container/sharder.py
View File

@ -197,8 +197,7 @@ def find_shrinking_candidates(broker, shrink_threshold, merge_size):
class CleavingContext(object):
def __init__(self, ref, cursor='', max_row=None, cleave_to_row=None,
last_cleave_to_row=None, cleaving_done=False,
misplaced_done=False, ranges_done=0, ranges_todo=0,
last_modified=None):
misplaced_done=False, ranges_done=0, ranges_todo=0):
self.ref = ref
self._cursor = None
self.cursor = cursor
@ -209,7 +208,6 @@ class CleavingContext(object):
self.misplaced_done = misplaced_done
self.ranges_done = ranges_done
self.ranges_todo = ranges_todo
self.last_modified = last_modified
def __iter__(self):
yield 'ref', self.ref
@ -221,7 +219,6 @@ class CleavingContext(object):
yield 'misplaced_done', self.misplaced_done
yield 'ranges_done', self.ranges_done
yield 'ranges_todo', self.ranges_todo
yield 'last_modified', self.last_modified
def _encode(cls, value):
if value is not None and six.PY2 and isinstance(value, six.text_type):
@ -250,17 +247,17 @@ class CleavingContext(object):
Returns all cleaving contexts stored in the broker.
:param broker:
:return: list of CleavingContexts
:return: list of tuples of (CleavingContext, timestamp)
"""
brokers = broker.get_brokers()
sysmeta = brokers[-1].get_sharding_sysmeta()
sysmeta = brokers[-1].get_sharding_sysmeta(include_timestamps=True)
for key, val in sysmeta.items():
for key, (val, timestamp) in sysmeta.items():
# If the value is of length 0, then the metadata is
# marked for deletion
if key.startswith("Context-") and len(val) > 0:
try:
yield cls(**json.loads(val))
yield cls(**json.loads(val)), timestamp
except ValueError:
continue
@ -288,7 +285,6 @@ class CleavingContext(object):
return cls(**data)
def store(self, broker):
self.last_modified = Timestamp.now().internal
broker.set_sharding_sysmeta('Context-' + self.ref,
json.dumps(dict(self)))
@ -754,12 +750,9 @@ class ContainerSharder(ContainerReplicator):
return True
def _audit_cleave_contexts(self, broker):
for context in CleavingContext.load_all(broker):
for context, last_mod in CleavingContext.load_all(broker):
now = Timestamp.now()
last_mod = context.last_modified
if not last_mod:
context.store(broker)
elif Timestamp(last_mod).timestamp + self.reclaim_age < \
if Timestamp(last_mod).timestamp + self.reclaim_age < \
now.timestamp:
context.delete(broker)

1
test/unit/cli/test_manage_shard_ranges.py
View File

@ -201,7 +201,6 @@ class TestManageShardRanges(unittest.TestCase):
' "cleaving_done": false,',
' "cursor": "",',
' "last_cleave_to_row": null,',
' "last_modified": null,',
' "max_row": -1,',
' "misplaced_done": false,',
' "ranges_done": 0,',

84
test/unit/container/test_sharder.py
View File

@ -4499,12 +4499,11 @@ class TestSharder(BaseTestSharder):
'misplaced_done': True,
'ranges_done': 2,
'ranges_todo': 4}
if last_modified is not None:
params['last_modified'] = last_modified
key = 'X-Container-Sysmeta-Shard-Context-%s' % id
with mock_timestamp_now(Timestamp(0)):
with mock_timestamp_now(Timestamp(last_modified)):
broker.update_metadata(
{key: (json.dumps(params), Timestamp.now().internal)})
{key: (json.dumps(params),
Timestamp(last_modified).internal)})
def get_context(id, broker):
data = broker.get_sharding_sysmeta().get('Context-%s' % id)
@ -4520,9 +4519,8 @@ class TestSharder(BaseTestSharder):
self.assertEqual(UNSHARDED, broker.get_db_state())
# Setup some cleaving contexts
id_missing_lm, id_old, id_newish = [str(uuid4()) for _ in range(3)]
contexts = ((id_missing_lm, None),
(id_old, 1),
id_old, id_newish = [str(uuid4()) for _ in range(2)]
contexts = ((id_old, 1),
(id_newish, reclaim_age // 2))
for id, last_modified in contexts:
add_cleave_context(id, last_modified)
@ -4531,12 +4529,6 @@ class TestSharder(BaseTestSharder):
with mock_timestamp_now(Timestamp(reclaim_age + 2)):
sharder._audit_cleave_contexts(broker)
# now is reclaim_age + 1, so the old should've been removed and the
# context with the missing last modified should now be reclaim + 1
missing_lm_ctx = get_context(id_missing_lm, broker)
self.assertEqual(missing_lm_ctx.last_modified,
Timestamp(reclaim_age + 2).internal)
old_ctx = get_context(id_old, broker)
self.assertEqual(old_ctx, "")
@ -4549,21 +4541,9 @@ class TestSharder(BaseTestSharder):
with mock_timestamp_now(Timestamp(reclaim_age * 2)):
sharder._audit_cleave_contexts(broker)
missing_lm_ctx = get_context(id_missing_lm, broker)
self.assertEqual(missing_lm_ctx.last_modified,
Timestamp(reclaim_age + 2).internal)
newish_ctx = get_context(id_newish, broker)
self.assertEqual(newish_ctx, "")
# Fast forward again and they're all cleaned up
with self._mock_sharder({'reclaim_age': str(reclaim_age)}) as sharder:
with mock_timestamp_now(Timestamp(reclaim_age * 3)):
sharder._audit_cleave_contexts(broker)
missing_lm_ctx = get_context(id_missing_lm, broker)
self.assertEqual(missing_lm_ctx, "")
class TestCleavingContext(BaseTestSharder):
def test_init(self):
@ -4583,7 +4563,6 @@ class TestCleavingContext(BaseTestSharder):
'max_row': 12,
'cleave_to_row': 11,
'last_cleave_to_row': 10,
'last_modified': None,
'cleaving_done': False,
'misplaced_done': True,
'ranges_done': 0,
@ -4603,7 +4582,6 @@ class TestCleavingContext(BaseTestSharder):
'max_row': 12,
'cleave_to_row': 11,
'last_cleave_to_row': 10,
'last_modified': None,
'cleaving_done': False,
'misplaced_done': True,
'ranges_done': 0,
@ -4654,6 +4632,7 @@ class TestCleavingContext(BaseTestSharder):
def test_load_all(self):
broker = self._make_broker()
last_ctx = None
timestamp = Timestamp.now()
db_ids = [str(uuid4()) for _ in range(6)]
for db_id in db_ids:
@ -4668,17 +4647,29 @@ class TestCleavingContext(BaseTestSharder):
'ranges_todo': 4}
key = 'X-Container-Sysmeta-Shard-Context-%s' % db_id
broker.update_metadata(
{key: (json.dumps(params), Timestamp.now().internal)})
for ctx in CleavingContext.load_all(broker):
{key: (json.dumps(params), timestamp.internal)})
first_ctx = None
for ctx, lm in CleavingContext.load_all(broker):
if not first_ctx:
first_ctx = ctx
last_ctx = ctx
self.assertIn(ctx.ref, db_ids)
self.assertEqual(lm, timestamp.internal)
# If a context is deleted (metadata is "") then it's skipped
last_ctx.delete(broker)
db_ids.remove(last_ctx.ref)
for ctx in CleavingContext.load_all(broker):
# and let's modify the first
with mock_timestamp_now() as new_timestamp:
first_ctx.store(broker)
for ctx, lm in CleavingContext.load_all(broker):
self.assertIn(ctx.ref, db_ids)
if ctx.ref == first_ctx.ref:
self.assertEqual(lm, new_timestamp.internal)
else:
self.assertEqual(lm, timestamp.internal)
def test_delete(self):
broker = self._make_broker()
@ -4710,36 +4701,6 @@ class TestCleavingContext(BaseTestSharder):
else:
self.fail("Deleted context 'Context-%s' not found")
def test_last_modified(self):
broker = self._make_broker()
db_id = broker.get_info()['id']
params = {'ref': db_id,
'cursor': 'curs',
'max_row': 2,
'cleave_to_row': 2,
'last_cleave_to_row': 1,
'cleaving_done': False,
'misplaced_done': True,
'ranges_done': 2,
'ranges_todo': 4}
key = 'X-Container-Sysmeta-Shard-Context-%s' % db_id
broker.update_metadata(
{key: (json.dumps(params), Timestamp.now().internal)})
ctx = CleavingContext.load(broker)
self.assertIsNone(ctx.last_modified)
# after a store/save the last_modified will be updated
ctx.store(broker)
ctx = CleavingContext.load(broker)
self.assertIsNotNone(ctx.last_modified)
last_modified = ctx.last_modified
# Store again it'll be updated again
ctx.store(broker)
ctx = CleavingContext.load(broker)
self.assertGreater(ctx.last_modified, last_modified)
def test_store(self):
broker = self._make_sharding_broker()
old_db_id = broker.get_brokers()[0].get_info()['id']
@ -4754,12 +4715,13 @@ class TestCleavingContext(BaseTestSharder):
'max_row': 12,
'cleave_to_row': 11,
'last_cleave_to_row': 2,
'last_modified': last_mod.internal,
'cleaving_done': True,
'misplaced_done': True,
'ranges_done': 2,
'ranges_todo': 4}
self.assertEqual(expected, data)
# last modified is the metadata timestamp
self.assertEqual(broker.metadata[key][1], last_mod.internal)
def test_store_add_row_load(self):
# adding row to older db changes only max_row in the context