Prevent replication wedging

This commit is contained in:
Andrew Morgan 2019-03-04 13:56:49 +00:00
parent 1beebe916f
commit 5f0c449dd5

View File

@ -451,7 +451,7 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
@defer.inlineCallbacks
def subscribe_to_stream(self, stream_name, token):
"""Subscribe the remote to a streams.
"""Subscribe the remote to a stream.
This invloves checking if they've missed anything and sending those
updates down if they have. During that time new updates for the stream
@ -478,7 +478,27 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
# Now we can send any updates that came in while we were subscribing
pending_rdata = self.pending_rdata.pop(stream_name, [])
batch_updates = []
for token, update in pending_rdata:
# If the token is null, it is part of a batch update. Batches
# are multiple updates that share a single token. To denote
# this, the token is set to None for all tokens in the batch
# except for the last. If we find a None token, we keep looking
# through tokens until we find one that is not None and then
# process all previous updates in the batch as if they had the
# final token.
if not token or len(batch_updates) > 0:
batch_updates.append(update)
if token and not token > current_token:
# This batch is older than current_token, dismiss
batch_updates = []
continue
if token:
# Send all updates that are part of this batch with the
# found token
for update in batch_updates:
self.send_command(RdataCommand(stream_name, token, update))
else:
# Only send updates newer than the current token
if token > current_token:
self.send_command(RdataCommand(stream_name, token, update))