diff --git a/changelog.d/3933.misc b/changelog.d/3933.misc
new file mode 100644
index 0000000000..6545871f55
--- /dev/null
+++ b/changelog.d/3933.misc
@@ -0,0 +1 @@
+Add a cache to get_destination_retry_timings
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index baf0379a68..ab54977a75 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -23,6 +23,7 @@ from canonicaljson import encode_canonical_json
from twisted.internet import defer
from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.util.caches.expiringcache import ExpiringCache
from ._base import SQLBaseStore, db_to_json
@@ -49,6 +50,8 @@ _UpdateTransactionRow = namedtuple(
)
)
+SENTINEL = object()
+
class TransactionStore(SQLBaseStore):
"""A collection of queries for handling PDUs.
@@ -59,6 +62,12 @@ class TransactionStore(SQLBaseStore):
self._clock.looping_call(self._start_cleanup_transactions, 30 * 60 * 1000)
+ self._destination_retry_cache = ExpiringCache(
+ cache_name="get_destination_retry_timings",
+ clock=self._clock,
+ expiry_ms=5 * 60 * 1000,
+ )
+
def get_received_txn_response(self, transaction_id, origin):
"""For an incoming transaction from a given origin, check if we have
already responded to it. If so, return the response code and response
@@ -155,6 +164,7 @@ class TransactionStore(SQLBaseStore):
"""
pass
+ @defer.inlineCallbacks
def get_destination_retry_timings(self, destination):
"""Gets the current retry timings (if any) for a given destination.
@@ -165,10 +175,20 @@ class TransactionStore(SQLBaseStore):
None if not retrying
Otherwise a dict for the retry scheme
"""
- return self.runInteraction(
+
+ result = self._destination_retry_cache.get(destination, SENTINEL)
+ if result is not SENTINEL:
+ defer.returnValue(result)
+
+ result = yield self.runInteraction(
"get_destination_retry_timings",
self._get_destination_retry_timings, destination)
+ # We don't hugely care about race conditions between getting and
+ # invalidating the cache, since we time out fairly quickly anyway.
+ self._destination_retry_cache[destination] = result
+ defer.returnValue(result)
+
def _get_destination_retry_timings(self, txn, destination):
result = self._simple_select_one_txn(
txn,
@@ -196,6 +216,7 @@ class TransactionStore(SQLBaseStore):
retry_interval (int) - how long until next retry in ms
"""
+ self._destination_retry_cache.pop(destination)
return self.runInteraction(
"set_destination_retry_timings",
self._set_destination_retry_timings,
diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index 9af4ec4aa8..f369780277 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -16,7 +16,7 @@
import logging
from collections import OrderedDict
-from six import itervalues
+from six import iteritems, itervalues
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.util.caches import register_cache
@@ -24,6 +24,9 @@ from synapse.util.caches import register_cache
logger = logging.getLogger(__name__)
+SENTINEL = object()
+
+
class ExpiringCache(object):
def __init__(self, cache_name, clock, max_len=0, expiry_ms=0,
reset_expiry_on_get=False, iterable=False):
@@ -95,6 +98,21 @@ class ExpiringCache(object):
return entry.value
+ def pop(self, key, default=SENTINEL):
+ """Removes and returns the value with the given key from the cache.
+
+ If the key isn't in the cache then `default` will be returned if
+ specified, otherwise `KeyError` will get raised.
+
+ Identical functionality to `dict.pop(..)`.
+ """
+
+ value = self._cache.pop(key, default)
+ if value is SENTINEL:
+ raise KeyError(key)
+
+ return value
+
def __contains__(self, key):
return key in self._cache
@@ -122,7 +140,7 @@ class ExpiringCache(object):
keys_to_delete = set()
- for key, cache_entry in self._cache.items():
+ for key, cache_entry in iteritems(self._cache):
if now - cache_entry.time > self._expiry_ms:
keys_to_delete.add(key)
@@ -146,6 +164,8 @@ class ExpiringCache(object):
class _CacheEntry(object):
+ __slots__ = ["time", "value"]
+
def __init__(self, time, value):
self.time = time
self.value = value
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