Retry event persistence on IntegrityError

Due to a bug in the porting script some backfilled events were not
correctly persisted, causing irrecoverable IntegrityErrors on future
attempts to persist those events.

This commit adds a retry mechanism invoked upon IntegrityError,
where when retried the tables are purged for all references to the
events being persisted.
This commit is contained in:
Erik Johnston 2016-08-04 15:02:15 +01:00
parent ea0b767114
commit 59fa91fe88

View file

@ -27,6 +27,7 @@ from synapse.api.errors import SynapseError
from canonicaljson import encode_canonical_json
from collections import deque, namedtuple, OrderedDict
from functools import wraps
import synapse
import synapse.metrics
@ -150,6 +151,27 @@ class _EventPeristenceQueue(object):
_EventCacheEntry = namedtuple("_EventCacheEntry", ("event", "redacted_event"))
def _retry_on_integrity_error(func):
"""Wraps a database function so that it gets retried on IntegrityError,
with `delete_existing=True` passed in.
Args:
func: function that returns a Deferred and accepts a `delete_existing` arg
"""
@wraps(func)
@defer.inlineCallbacks
def f(self, *args, **kwargs):
try:
res = yield func(self, *args, **kwargs)
defer.returnValue(res)
except self.database_engine.module.IntegrityError:
logger.exception("IntegrityError, retrying.")
res = yield func(self, *args, delete_existing=True, **kwargs)
defer.returnValue(res)
return f
class EventsStore(SQLBaseStore):
EVENT_ORIGIN_SERVER_TS_NAME = "event_origin_server_ts"
EVENT_FIELDS_SENDER_URL_UPDATE_NAME = "event_fields_sender_url"
@ -229,8 +251,10 @@ class EventsStore(SQLBaseStore):
self._event_persist_queue.handle_queue(room_id, persisting_queue)
@_retry_on_integrity_error
@defer.inlineCallbacks
def _persist_events(self, events_and_contexts, backfilled=False):
def _persist_events(self, events_and_contexts, backfilled=False,
delete_existing=False):
if not events_and_contexts:
return
@ -273,12 +297,15 @@ class EventsStore(SQLBaseStore):
self._persist_events_txn,
events_and_contexts=chunk,
backfilled=backfilled,
delete_existing=delete_existing,
)
persist_event_counter.inc_by(len(chunk))
@_retry_on_integrity_error
@defer.inlineCallbacks
@log_function
def _persist_event(self, event, context, current_state=None, backfilled=False):
def _persist_event(self, event, context, current_state=None, backfilled=False,
delete_existing=False):
try:
with self._stream_id_gen.get_next() as stream_ordering:
with self._state_groups_id_gen.get_next() as state_group_id:
@ -291,6 +318,7 @@ class EventsStore(SQLBaseStore):
context=context,
current_state=current_state,
backfilled=backfilled,
delete_existing=delete_existing,
)
persist_event_counter.inc()
except _RollbackButIsFineException:
@ -353,7 +381,8 @@ class EventsStore(SQLBaseStore):
defer.returnValue({e.event_id: e for e in events})
@log_function
def _persist_event_txn(self, txn, event, context, current_state, backfilled=False):
def _persist_event_txn(self, txn, event, context, current_state, backfilled=False,
delete_existing=False):
# We purposefully do this first since if we include a `current_state`
# key, we *want* to update the `current_state_events` table
if current_state:
@ -393,15 +422,20 @@ class EventsStore(SQLBaseStore):
txn,
[(event, context)],
backfilled=backfilled,
delete_existing=delete_existing,
)
@log_function
def _persist_events_txn(self, txn, events_and_contexts, backfilled):
def _persist_events_txn(self, txn, events_and_contexts, backfilled,
delete_existing=False):
"""Insert some number of room events into the necessary database tables.
Rejected events are only inserted into the events table, the events_json table,
and the rejections table. Things reading from those table will need to check
whether the event was rejected.
If delete_existing is True then existing events will be purged from the
database before insertion. This is useful when retrying due to IntegrityError.
"""
# Ensure that we don't have the same event twice.
# Pick the earliest non-outlier if there is one, else the earliest one.
@ -537,6 +571,33 @@ class EventsStore(SQLBaseStore):
]
}
if delete_existing:
# For paranoia reasons, we go and delete all the existing entries
# for these events so we can reinsert them.
# This gets around any problems with some tables already having
# entries.
for table in (
"events",
"event_json",
"event_content_hashes",
"event_destinations",
"event_edge_hashes",
"event_edges",
"event_forward_extremities",
"event_push_actions",
"event_reference_hashes",
"event_search",
"event_signatures",
"event_to_state_groups",
"rejections",
"redactions",
):
txn.executemany(
"DELETE FROM %s WHERE event_id = ?" % (table,),
[ev for ev, _ in events_and_contexts]
)
self._simple_insert_many_txn(
txn,
table="event_json",