From 4b10880da363efed5d066191190237f1c64fddfd Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Tue, 3 Aug 2021 14:45:04 +0100 Subject: [PATCH] Make sync response cache time configurable. (#10513) --- changelog.d/10513.feature | 1 + docs/sample_config.yaml | 9 +++++++++ synapse/config/cache.py | 13 +++++++++++++ synapse/handlers/sync.py | 14 +++++++++++--- 4 files changed, 34 insertions(+), 3 deletions(-) create mode 100644 changelog.d/10513.feature diff --git a/changelog.d/10513.feature b/changelog.d/10513.feature new file mode 100644 index 000000000..153b2df7b --- /dev/null +++ b/changelog.d/10513.feature @@ -0,0 +1 @@ +Add a configuration setting for the time a `/sync` response is cached for. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index 1a217f35d..a2efc1410 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -711,6 +711,15 @@ caches: # #expiry_time: 30m + # Controls how long the results of a /sync request are cached for after + # a successful response is returned. A higher duration can help clients with + # intermittent connections, at the cost of higher memory usage. + # + # By default, this is zero, which means that sync responses are not cached + # at all. + # + #sync_response_cache_duration: 2m + ## Database ## diff --git a/synapse/config/cache.py b/synapse/config/cache.py index 8d5f38b5d..d119427ad 100644 --- a/synapse/config/cache.py +++ b/synapse/config/cache.py @@ -151,6 +151,15 @@ class CacheConfig(Config): # entries are never evicted based on time. # #expiry_time: 30m + + # Controls how long the results of a /sync request are cached for after + # a successful response is returned. A higher duration can help clients with + # intermittent connections, at the cost of higher memory usage. + # + # By default, this is zero, which means that sync responses are not cached + # at all. + # + #sync_response_cache_duration: 2m """ def read_config(self, config, **kwargs): @@ -212,6 +221,10 @@ class CacheConfig(Config): else: self.expiry_time_msec = None + self.sync_response_cache_duration = self.parse_duration( + cache_config.get("sync_response_cache_duration", 0) + ) + # Resize all caches (if necessary) with the new factors we've loaded self.resize_all_caches() diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index f30bfcc93..590642f51 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -269,14 +269,22 @@ class SyncHandler: self.presence_handler = hs.get_presence_handler() self.event_sources = hs.get_event_sources() self.clock = hs.get_clock() - self.response_cache: ResponseCache[SyncRequestKey] = ResponseCache( - hs.get_clock(), "sync" - ) self.state = hs.get_state_handler() self.auth = hs.get_auth() self.storage = hs.get_storage() self.state_store = self.storage.state + # TODO: flush cache entries on subsequent sync request. + # Once we get the next /sync request (ie, one with the same access token + # that sets 'since' to 'next_batch'), we know that device won't need a + # cached result any more, and we could flush the entry from the cache to save + # memory. + self.response_cache: ResponseCache[SyncRequestKey] = ResponseCache( + hs.get_clock(), + "sync", + timeout_ms=hs.config.caches.sync_response_cache_duration, + ) + # ExpiringCache((User, Device)) -> LruCache(user_id => event_id) self.lazy_loaded_members_cache: ExpiringCache[ Tuple[str, Optional[str]], LruCache[str, str]