From 79eded1ae4f0d341918f5c58076f1e60cd400e8a Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Fri, 21 Sep 2018 14:52:21 +0100 Subject: [PATCH 1/6] Make ExpiringCache slightly more performant --- synapse/util/caches/expiringcache.py | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py index 921a9c5b2..48ca2d634 100644 --- a/synapse/util/caches/expiringcache.py +++ b/synapse/util/caches/expiringcache.py @@ -16,6 +16,8 @@ import logging from collections import OrderedDict +from six import iteritems + from synapse.metrics.background_process_metrics import run_as_background_process from synapse.util.caches import register_cache @@ -127,7 +129,7 @@ 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) @@ -149,6 +151,8 @@ class ExpiringCache(object): class _CacheEntry(object): + __slots__ = ["time", "value"] + def __init__(self, time, value): self.time = time self.value = value From fdd1a62e8d09ddccbe685fe7d7840990a9c06241 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Fri, 21 Sep 2018 14:55:47 +0100 Subject: [PATCH 2/6] Add a five minute cache to get_destination_retry_timings Hopefully helps with #3931 --- synapse/storage/transactions.py | 23 ++++++++++++++++++++++- synapse/util/caches/expiringcache.py | 13 +++++++++++++ 2 files changed, 35 insertions(+), 1 deletion(-) diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py index baf0379a6..ab54977a7 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 48ca2d634..346669e4c 100644 --- a/synapse/util/caches/expiringcache.py +++ b/synapse/util/caches/expiringcache.py @@ -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): @@ -102,6 +105,16 @@ class ExpiringCache(object): return entry.value + def pop(self, key, default=None): + value = self._cache.pop(key, SENTINEL) + if value is SENTINEL: + return default + + if self.iterable: + self._size_estimate -= len(value.value) + + return value + def __contains__(self, key): return key in self._cache From 5230bc147159d6ffbe04d27e695064cac44166d2 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Fri, 21 Sep 2018 15:05:37 +0100 Subject: [PATCH 3/6] Newsfile --- changelog.d/3933.misc | 1 + 1 file changed, 1 insertion(+) create mode 100644 changelog.d/3933.misc diff --git a/changelog.d/3933.misc b/changelog.d/3933.misc new file mode 100644 index 000000000..6545871f5 --- /dev/null +++ b/changelog.d/3933.misc @@ -0,0 +1 @@ +Add a cache to get_destination_retry_timings From 19dc676d1aaf66a45c9a1810132952f7ae3ca2aa Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Fri, 21 Sep 2018 16:25:42 +0100 Subject: [PATCH 4/6] Fix ExpiringCache.__len__ to be accurate It used to try and produce an estimate, which was sometimes negative. This caused metrics to be sad, so lets always just calculate it from scratch. --- synapse/util/caches/expiringcache.py | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py index 346669e4c..8ac56d85f 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 iteritems +from six import iteritems, itervalues from synapse.metrics.background_process_metrics import run_as_background_process from synapse.util.caches import register_cache @@ -59,8 +59,6 @@ class ExpiringCache(object): self.iterable = iterable - self._size_estimate = 0 - self.metrics = register_cache("expiring", cache_name, self) if not self._expiry_ms: @@ -79,16 +77,11 @@ class ExpiringCache(object): now = self._clock.time_msec() self._cache[key] = _CacheEntry(now, value) - if self.iterable: - self._size_estimate += len(value) - # Evict if there are now too many items while self._max_len and len(self) > self._max_len: _key, value = self._cache.popitem(last=False) if self.iterable: - removed_len = len(value.value) - self.metrics.inc_evictions(removed_len) - self._size_estimate -= removed_len + self.metrics.inc_evictions(len(value.value)) else: self.metrics.inc_evictions() @@ -111,7 +104,9 @@ class ExpiringCache(object): return default if self.iterable: - self._size_estimate -= len(value.value) + self.metrics.inc_evictions(len(value.value)) + else: + self.metrics.inc_evictions() return value @@ -149,7 +144,9 @@ class ExpiringCache(object): for k in keys_to_delete: value = self._cache.pop(k) if self.iterable: - self._size_estimate -= len(value.value) + self.metrics.inc_evictions(len(value.value)) + else: + self.metrics.inc_evictions() logger.debug( "[%s] _prune_cache before: %d, after len: %d", @@ -158,7 +155,7 @@ class ExpiringCache(object): def __len__(self): if self.iterable: - return self._size_estimate + return sum(len(entry.value) for entry in itervalues(self._cache)) else: return len(self._cache) From 8ea887856c1bcb97c90d88fe20f7f82ed7f48967 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Mon, 1 Oct 2018 11:59:52 +0100 Subject: [PATCH 5/6] Don't update eviction metrics on explicit removal --- synapse/util/caches/expiringcache.py | 5 ----- 1 file changed, 5 deletions(-) diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py index 8ac56d85f..f2f55ba6c 100644 --- a/synapse/util/caches/expiringcache.py +++ b/synapse/util/caches/expiringcache.py @@ -103,11 +103,6 @@ class ExpiringCache(object): if value is SENTINEL: return default - if self.iterable: - self.metrics.inc_evictions(len(value.value)) - else: - self.metrics.inc_evictions() - return value def __contains__(self, key): From 4f3e3ac192f2c5ff37198f50af99bc8fbd57beca Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Mon, 1 Oct 2018 12:25:27 +0100 Subject: [PATCH 6/6] Correctly match 'dict.pop' api --- synapse/util/caches/expiringcache.py | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py index f2f55ba6c..f36978027 100644 --- a/synapse/util/caches/expiringcache.py +++ b/synapse/util/caches/expiringcache.py @@ -98,10 +98,18 @@ class ExpiringCache(object): return entry.value - def pop(self, key, default=None): - value = self._cache.pop(key, SENTINEL) + 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: - return default + raise KeyError(key) return value