openstack/deb-python-cassandra-driver
Code Issues Proposed changes

More efficient replica map building for NTS

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This commit is contained in:
Tyler Hobbs
2013-09-27 11:42:32 -05:00
parent c85a323d63
commit 24b29b7a44
1 changed files with 21 additions and 15 deletions
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36
cassandra/metadata.py
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@@ -386,27 +386,30 @@ class NetworkTopologyStrategy(ReplicationStrategy):
def make_token_replica_map(self, token_to_host_owner, ring):
# note: this does not account for hosts having different racks
replica_map = defaultdict(set)
for i in range(len(ring)):
remaining = dict((dc, int(rf))
for dc, rf in self.dc_replication_factors.items()
if rf > 0)
for j in range(len(ring)):
token = ring[(i + j) % len(ring)]
host = token_to_host_owner[token]
if not host.datacenter:
continue
ring_len = len(ring)
ring_len_range = range(ring_len)
dc_rf_map = dict((dc, int(rf))
for dc, rf in self.dc_replication_factors.items() if rf > 0)
dcs = dict((h, h.datacenter) for h in set(token_to_host_owner.values()))
if not host.datacenter in remaining:
for i in ring_len_range:
remaining = dc_rf_map.copy()
for j in ring_len_range:
token = ring[(i + j) % ring_len]
host = token_to_host_owner[token]
dc = dcs[host]
if not dc in remaining:
# we already have all replicas for this DC
continue
replica_map[ring[i]].add(host)
remaining[host.datacenter] -= 1
if remaining[host.datacenter] == 0:
del remaining[host.datacenter]
if not remaining:
break
if remaining[dc] == 1:
del remaining[dc]
if not remaining:
break
else:
remaining[dc] -= 1
return replica_map
@@ -819,6 +822,9 @@ class Token(object):
else:
return 1
def __eq__(self, other):
return self.value == other.value
def __hash__(self):
return self.value