From 284d85dee34d1d79ff92c38799dabdc28a713793 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Tue, 14 May 2024 15:08:46 +0100 Subject: [PATCH] Cache literal sync filter validation (#17186) The sliding sync proxy (amongst other things) use literal json blobs as filters, and repeatedly validating them takes a bunch of CPU. --- changelog.d/17186.misc | 1 + synapse/rest/client/sync.py | 14 +++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) create mode 100644 changelog.d/17186.misc diff --git a/changelog.d/17186.misc b/changelog.d/17186.misc new file mode 100644 index 000000000..358209d5a --- /dev/null +++ b/changelog.d/17186.misc @@ -0,0 +1 @@ +Cache literal sync filter validation for performance. diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py index 2b103ca6a..d19aaf0e2 100644 --- a/synapse/rest/client/sync.py +++ b/synapse/rest/client/sync.py @@ -47,6 +47,7 @@ from synapse.http.site import SynapseRequest from synapse.logging.opentracing import trace_with_opname from synapse.types import JsonDict, Requester, StreamToken from synapse.util import json_decoder +from synapse.util.caches.lrucache import LruCache from ._base import client_patterns, set_timeline_upper_limit @@ -110,6 +111,11 @@ class SyncRestServlet(RestServlet): self._msc2654_enabled = hs.config.experimental.msc2654_enabled self._msc3773_enabled = hs.config.experimental.msc3773_enabled + self._json_filter_cache: LruCache[str, bool] = LruCache( + max_size=1000, + cache_name="sync_valid_filter", + ) + async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]: # This will always be set by the time Twisted calls us. assert request.args is not None @@ -177,7 +183,13 @@ class SyncRestServlet(RestServlet): filter_object = json_decoder.decode(filter_id) except Exception: raise SynapseError(400, "Invalid filter JSON", errcode=Codes.NOT_JSON) - self.filtering.check_valid_filter(filter_object) + + # We cache the validation, as this can get quite expensive if people use + # a literal json blob as a query param. + if not self._json_filter_cache.get(filter_id): + self.filtering.check_valid_filter(filter_object) + self._json_filter_cache[filter_id] = True + set_timeline_upper_limit( filter_object, self.hs.config.server.filter_timeline_limit )