openstack
/
swift
Code Issues Proposed changes

Always update shard brokers with their own range and sharding metadata 

There is no need to conditionally update shard brokers when they are
created. The 'force' flag was a leftover from when own shard range
state was stored in sysmeta and the most recent writer of state would
take precedence.  We consequently needed to avoid updating the
sharding meta-timestamp in sysmeta as a side-effect of getting the
shard broker.

Since [1] the meta-timestamp is managed by the shard range merging
logic so that the most recent time takes precedence rather than the
most recent writer.

[1] Related-Change: Ie65cd4ce0abc98452163f6acdfad3cce5cdd216f

Change-Id: I3f3d13cf1caa684260f2ddfdb731ca941336f319
This commit is contained in:
Alistair Coles 2018-04-27 10:41:44 +01:00
parent bfbc18c2f6
commit 55bc15b873
1 changed files with 15 additions and 16 deletions
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31
swift/container/sharder.py
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@ -534,17 +534,20 @@ class ContainerSharder(ContainerReplicator):
results = pool.waitall(None)
return results.count(True) >= quorum_size(self.ring.replica_count)
def _get_shard_broker(self, shard_range, root_path, policy_index,
force=False):
def _get_shard_broker(self, shard_range, root_path, policy_index):
"""
Get a container broker for given shard range.
Get a broker for a container db for the given shard range. If one of
the shard container's primary nodes is a local device then that will be
chosen for the db, otherwise the first of the shard container's handoff
nodes that is local will be chosen.
:param shard_range: a :class:`~swift.common.utils.ShardRange`
:param root_path: the path of the shard's root container
:param policy_index: the storage policy index
:param force: if True set the broker's sharding metadata even if
sharding metadata already exists
:returns: a shard container broker
:returns: a tuple of ``(part, broker, node_id)`` where ``part`` is the
shard container's partition, ``broker`` is an instance of
:class:`~swift.container.backend.ContainerBroker`,
``node_id`` is the id of the selected node.
"""
part = self.ring.get_part(shard_range.account, shard_range.container)
node = self.find_local_handoff_for_part(part)
@ -559,13 +562,11 @@ class ContainerSharder(ContainerReplicator):
# Get the valid info into the broker.container, etc
shard_broker.get_info()
if not shard_broker.get_sharding_info('Root') or force:
shard_broker.merge_shard_ranges(shard_range)
shard_broker.update_sharding_info({'Root': root_path})
shard_broker.update_metadata({
'X-Container-Sysmeta-Sharding':
('True', Timestamp.now().internal)})
shard_broker.merge_shard_ranges(shard_range)
shard_broker.update_sharding_info({'Root': root_path})
shard_broker.update_metadata({
'X-Container-Sysmeta-Sharding':
('True', Timestamp.now().internal)})
return part, shard_broker, node['id']
@ -1070,10 +1071,8 @@ class ContainerSharder(ContainerReplicator):
start = time.time()
policy_index = broker.storage_policy_index
try:
# use force here because we may want to update existing shard
# metadata timestamps
shard_part, shard_broker, node_id = self._get_shard_broker(
shard_range, broker.root_path, policy_index, force=True)
shard_range, broker.root_path, policy_index)
except DeviceUnavailable as duex:
self.logger.warning(str(duex))
self._increment_stat('cleaved', 'failure', statsd=True)