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track replication destination health, and perform exponential back-off when sending transactions. does *not* yet retry transactions, but drops them on the floor if waiting for a server to recover.

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This commit is contained in:
Matthew Hodgson 2014-12-07 02:26:07 +00:00
parent ce212eb83a
commit aed62a3583
9 changed files with 156 additions and 18 deletions
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43
synapse/federation/replication.py
View file

@ -723,6 +723,8 @@ class _TransactionQueue(object):
deferreds = []
for destination in destinations:
# XXX: why don't we specify an errback for this deferred
# like we do for EDUs? --matthew
deferred = defer.Deferred()
self.pending_pdus_by_dest.setdefault(destination, []).append(
(pdu, deferred, order)
@ -738,6 +740,9 @@ class _TransactionQueue(object):
# NO inlineCallbacks
def enqueue_edu(self, edu):
destination = edu.destination
if destination == self.server_name:
return
deferred = defer.Deferred()
self.pending_edus_by_dest.setdefault(destination, []).append(
@ -766,14 +771,23 @@ class _TransactionQueue(object):
)
yield deferred
@defer.inlineCallbacks
@log_function
def _attempt_new_transaction(self, destination):
(retry_last_ts, retry_interval) = self.store.get_destination_retry_timings(destination)
if retry_last_ts + retry_interval > int(self._clock.time_msec()):
logger.info("TX [%s] not ready for retry yet - dropping transaction for now")
return
if destination in self.pending_transactions:
# XXX: pending_transactions can get stuck on by a never-ending request
# at which point pending_pdus_by_dest just keeps growing.
# we need application-layer timeouts of some flavour of these requests
return
# list of (pending_pdu, deferred, order)
# list of (pending_pdu, deferred, order)
pending_pdus = self.pending_pdus_by_dest.pop(destination, [])
pending_edus = self.pending_edus_by_dest.pop(destination, [])
pending_failures = self.pending_failures_by_dest.pop(destination, [])
@ -781,7 +795,8 @@ class _TransactionQueue(object):
if not pending_pdus and not pending_edus and not pending_failures:
return
logger.debug("TX [%s] Attempting new transaction", destination)
logger.debug("TX [%s] Attempting new transaction (pdus: %d, edus: %d, failures: %d)",
destination, len(pending_pdus), len(pending_edus), len(pending_failures))
# Sort based on the order field
pending_pdus.sort(key=lambda t: t[2])
@ -814,7 +829,7 @@ class _TransactionQueue(object):
yield self.transaction_actions.prepare_to_send(transaction)
logger.debug("TX [%s] Persisted transaction", destination)
logger.debug("TX [%s] Sending transaction...", destination)
logger.info("TX [%s] Sending transaction [%s]", destination, transaction.transaction_id)
# Actually send the transaction
@ -835,6 +850,8 @@ class _TransactionQueue(object):
transaction, json_data_cb
)
logger.info("TX [%s] got %d response", destination, code)
logger.debug("TX [%s] Sent transaction", destination)
logger.debug("TX [%s] Marking as delivered...", destination)
@ -849,6 +866,7 @@ class _TransactionQueue(object):
if code == 200:
deferred.callback(None)
else:
start_retrying(destination, retry_interval)
deferred.errback(RuntimeError("Got status %d" % code))
# Ensures we don't continue until all callbacks on that
@ -861,12 +879,12 @@ class _TransactionQueue(object):
logger.debug("TX [%s] Yielded to callbacks", destination)
except Exception as e:
logger.error("TX Problem in _attempt_transaction")
# We capture this here as there as nothing actually listens
# for this finishing functions deferred.
logger.exception(e)
logger.exception("TX [%s] Problem in _attempt_transaction: %s", destination, e)
start_retrying(destination, retry_interval)
for deferred in deferreds:
if not deferred.called:
deferred.errback(e)
@ -877,3 +895,14 @@ class _TransactionQueue(object):
# Check to see if there is anything else to send.
self._attempt_new_transaction(destination)
def start_retrying(destination, retry_interval):
# track that this destination is having problems and we should
# give it a chance to recover before trying it again
if retry_interval:
retry_interval *= 2
else:
retry_interval = 2 # try again at first after 2 seconds
self.store.set_destination_retry_timings(destination,
int(self._clock.time_msec()), retry_interval)

2
synapse/federation/transport.py
View file

@ -155,7 +155,7 @@ class TransportLayer(object):
@defer.inlineCallbacks
@log_function
def send_transaction(self, transaction, json_data_callback=None):
""" Sends the given Transaction to it's destination
""" Sends the given Transaction to its destination
Args:
transaction (Transaction)

16
synapse/http/matrixfederationclient.py
View file

@ -89,7 +89,7 @@ class MatrixFederationHttpClient(object):
("", "", path_bytes, param_bytes, query_bytes, "",)
)
logger.debug("Sending request to %s: %s %s",
logger.info("Sending request to %s: %s %s",
destination, method, url_bytes)
logger.debug(
@ -101,7 +101,10 @@ class MatrixFederationHttpClient(object):
]
)
retries_left = 5
# was 5; for now, let's only try once at the HTTP layer and then
# rely on transaction-layer retries for exponential backoff and
# getting the message through.
retries_left = 0
endpoint = self._getEndpoint(reactor, destination)
@ -131,7 +134,8 @@ class MatrixFederationHttpClient(object):
e)
raise SynapseError(400, "Domain specified not found.")
logger.exception("Got error in _create_request")
logger.exception("Sending request failed to %s: %s %s : %s",
destination, method, url_bytes, e)
_print_ex(e)
if retries_left:
@ -140,15 +144,15 @@ class MatrixFederationHttpClient(object):
else:
raise
logger.info("Received response %d %s for %s: %s %s",
response.code, response.phrase, destination, method, url_bytes)
if 200 <= response.code < 300:
# We need to update the transactions table to say it was sent?
pass
else:
# :'(
# Update transactions table?
logger.error(
"Got response %d %s", response.code, response.phrase
)
raise CodeMessageException(
response.code, response.phrase
)

2
synapse/rest/transactions.py
View file

@ -19,7 +19,7 @@ import logging
logger = logging.getLogger(__name__)
# FIXME: elsewhere we use FooStore to indicate something in the storage layer...
class HttpTransactionStore(object):
def __init__(self):

2
synapse/storage/__init__.py
View file

@ -67,7 +67,7 @@ SCHEMAS = [
# Remember to update this number every time an incompatible change is made to
# database schema files, so the users will be informed on server restarts.
SCHEMA_VERSION = 8
SCHEMA_VERSION = 9
class _RollbackButIsFineException(Exception):

2
synapse/storage/_base.py
View file

@ -650,7 +650,7 @@ class JoinHelper(object):
to dump the results into.
Attributes:
taples (list): List of `Table` classes
tables (list): List of `Table` classes
EntryType (type)
"""

23
synapse/storage/schema/delta/v9.sql Normal file
View file

@ -0,0 +1,23 @@
/* Copyright 2014 OpenMarket Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
-- To track destination health
CREATE TABLE IF NOT EXISTS destinations(
destination TEXT PRIMARY KEY,
retry_last_ts INTEGER,
retry_interval INTEGER
);
PRAGMA user_version = 9;

6
synapse/storage/schema/transactions.sql
View file

@ -59,3 +59,9 @@ CREATE INDEX IF NOT EXISTS transaction_id_to_pdu_tx ON transaction_id_to_pdu(tra
CREATE INDEX IF NOT EXISTS transaction_id_to_pdu_dest ON transaction_id_to_pdu(destination);
CREATE INDEX IF NOT EXISTS transaction_id_to_pdu_index ON transaction_id_to_pdu(transaction_id, destination);
-- To track destination health
CREATE TABLE IF NOT EXISTS destinations(
destination TEXT PRIMARY KEY,
retry_last_ts INTEGER,
retry_interval INTEGER
);

78
synapse/storage/transactions.py
View file

@ -114,7 +114,7 @@ class TransactionStore(SQLBaseStore):
def _prep_send_transaction(self, txn, transaction_id, destination,
origin_server_ts):
# First we find out what the prev_txs should be.
# First we find out what the prev_txns should be.
# Since we know that we are only sending one transaction at a time,
# we can simply take the last one.
query = "%s ORDER BY id DESC LIMIT 1" % (
@ -205,6 +205,71 @@ class TransactionStore(SQLBaseStore):
return ReceivedTransactionsTable.decode_results(txn.fetchall())
def get_destination_retry_timings(self, destination):
"""Gets the current retry timings (if any) for a given destination.
Args:
destination (str)
Returns:
None if not retrying
tuple: (retry_last_ts, retry_interval)
retry_ts: time of last retry attempt in unix epoch ms
retry_interval: how long until next retry in ms
"""
return self.runInteraction(
"get_destination_retry_timings",
self._get_destination_retry_timings, destination)
def _get_destination_retry_timings(cls, txn, destination):
query = DestinationsTable.select_statement("destination = ?")
txn.execute(query, (destination,))
result = DestinationsTable.decode_single_result(txn.fetchone())
if result and result[0] > 0:
return result
else:
return None
def set_destination_retry_timings(self, destination):
"""Sets the current retry timings for a given destination.
Both timings should be zero if retrying is no longer occuring.
Args:
destination (str)
retry_last_ts (int) - time of last retry attempt in unix epoch ms
retry_interval (int) - how long until next retry in ms
"""
return self.runInteraction(
"set_destination_retry_timings",
self._set_destination_retry_timings, destination, retry_last_ts, retry_interval)
def _set_destination_retry_timings(cls, txn, destination, retry_last_ts, retry_interval):
query = (
"INSERT OR REPLACE INTO %s "
"(retry_last_ts, retry_interval) "
"VALUES (?, ?) "
"WHERE destination = ?"
) % DestinationsTable.table_name
txn.execute(query, (retry_last_ts, retry_interval, destination))
def get_destinations_needing_retry(self):
"""Get all destinations which are due a retry for sending a transaction.
Returns:
list: A list of `DestinationsTable.EntryType`
"""
return self.runInteraction(
"get_destinations_needing_retry",
self._get_destinations_needing_retry
)
def _get_destinations_needing_retry(cls, txn):
where = "retry_last_ts > 0 and retry_next_ts < now()"
query = DestinationsTable.select_statement(where)
txn.execute(query)
return DestinationsTable.decode_results(txn.fetchall())
class ReceivedTransactionsTable(Table):
table_name = "received_transactions"
@ -247,3 +312,14 @@ class TransactionsToPduTable(Table):
]
EntryType = namedtuple("TransactionsToPduEntry", fields)
class DestinationsTable(Table):
table_name = "destinations"
fields = [
"destination",
"retry_last_ts",
"retry_interval",
]
EntryType = namedtuple("DestinationsEntry", fields)