diff --git a/Cargo.lock b/Cargo.lock
index 2a7791ce15245e8381c40cd5e354e9def4480abf..cf60ae4385ff7acb7c9fc69a7ff8745ad8475cb6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2045,7 +2045,7 @@ dependencies = [
 [[package]]
 name = "ruma"
 version = "0.3.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "assign",
  "js_int",
@@ -2066,7 +2066,7 @@ dependencies = [
 [[package]]
 name = "ruma-api"
 version = "0.18.3"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "bytes",
  "http",
@@ -2082,7 +2082,7 @@ dependencies = [
 [[package]]
 name = "ruma-api-macros"
 version = "0.18.3"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "proc-macro-crate",
  "proc-macro2",
@@ -2093,7 +2093,7 @@ dependencies = [
 [[package]]
 name = "ruma-appservice-api"
 version = "0.4.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "ruma-api",
  "ruma-common",
@@ -2107,7 +2107,7 @@ dependencies = [
 [[package]]
 name = "ruma-client-api"
 version = "0.12.2"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "assign",
  "bytes",
@@ -2127,7 +2127,7 @@ dependencies = [
 [[package]]
 name = "ruma-common"
 version = "0.6.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "indexmap",
  "js_int",
@@ -2142,7 +2142,7 @@ dependencies = [
 [[package]]
 name = "ruma-events"
 version = "0.24.4"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "indoc",
  "js_int",
@@ -2158,7 +2158,7 @@ dependencies = [
 [[package]]
 name = "ruma-events-macros"
 version = "0.24.4"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "proc-macro-crate",
  "proc-macro2",
@@ -2169,7 +2169,7 @@ dependencies = [
 [[package]]
 name = "ruma-federation-api"
 version = "0.3.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "js_int",
  "ruma-api",
@@ -2184,7 +2184,7 @@ dependencies = [
 [[package]]
 name = "ruma-identifiers"
 version = "0.20.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "paste",
  "rand 0.8.4",
@@ -2198,7 +2198,7 @@ dependencies = [
 [[package]]
 name = "ruma-identifiers-macros"
 version = "0.20.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "quote",
  "ruma-identifiers-validation",
@@ -2208,7 +2208,7 @@ dependencies = [
 [[package]]
 name = "ruma-identifiers-validation"
 version = "0.5.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "thiserror",
 ]
@@ -2216,7 +2216,7 @@ dependencies = [
 [[package]]
 name = "ruma-identity-service-api"
 version = "0.3.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "js_int",
  "ruma-api",
@@ -2229,7 +2229,7 @@ dependencies = [
 [[package]]
 name = "ruma-push-gateway-api"
 version = "0.3.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "js_int",
  "ruma-api",
@@ -2244,7 +2244,7 @@ dependencies = [
 [[package]]
 name = "ruma-serde"
 version = "0.5.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "bytes",
  "form_urlencoded",
@@ -2258,7 +2258,7 @@ dependencies = [
 [[package]]
 name = "ruma-serde-macros"
 version = "0.5.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "proc-macro-crate",
  "proc-macro2",
@@ -2269,7 +2269,7 @@ dependencies = [
 [[package]]
 name = "ruma-signatures"
 version = "0.9.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "base64 0.13.0",
  "ed25519-dalek",
@@ -2286,7 +2286,7 @@ dependencies = [
 [[package]]
 name = "ruma-state-res"
 version = "0.3.0"
-source = "git+https://github.com/DevinR528/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
+source = "git+https://github.com/timokoesters/ruma?rev=2215049b60a1c3358f5a52215adf1e7bb88619a1#2215049b60a1c3358f5a52215adf1e7bb88619a1"
 dependencies = [
  "itertools 0.10.1",
  "js_int",
diff --git a/Cargo.toml b/Cargo.toml
index 291f51e673d7d1adecb1f3f1c67ada52a6ffb0ff..0b0dda94dbeb471bf3c2c1b830f96f27b3a9fc42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ rocket = { version = "0.5.0-rc.1", features = ["tls"] } # Used to handle request
 
 # Used for matrix spec type definitions and helpers
 #ruma = { git = "https://github.com/ruma/ruma", rev = "f5ab038e22421ed338396ece977b6b2844772ced", features = ["compat", "rand", "appservice-api-c", "client-api", "federation-api", "push-gateway-api-c", "state-res", "unstable-pre-spec", "unstable-exhaustive-types"] }
-ruma = { git = "https://github.com/DevinR528/ruma", rev = "2215049b60a1c3358f5a52215adf1e7bb88619a1", features = ["compat", "rand", "appservice-api-c", "client-api", "federation-api", "push-gateway-api-c", "state-res", "unstable-pre-spec", "unstable-exhaustive-types"] }
+ruma = { git = "https://github.com/timokoesters/ruma", rev = "2215049b60a1c3358f5a52215adf1e7bb88619a1", features = ["compat", "rand", "appservice-api-c", "client-api", "federation-api", "push-gateway-api-c", "state-res", "unstable-pre-spec", "unstable-exhaustive-types"] }
 #ruma = { path = "../ruma/crates/ruma", features = ["compat", "rand", "appservice-api-c", "client-api", "federation-api", "push-gateway-api-c", "state-res", "unstable-pre-spec", "unstable-exhaustive-types"] }
 
 # Used for long polling and federation sender, should be the same as rocket::tokio
diff --git a/src/database/rooms.rs b/src/database/rooms.rs
index 8bb32fead24c7aa7158a3e65de6c3daf3acedea3..0d99c52b8bc6f071bcd71c6a0fd94b2a8642bd47 100644
--- a/src/database/rooms.rs
+++ b/src/database/rooms.rs
@@ -19,7 +19,7 @@
     },
     push::{self, Action, Tweak},
     serde::{CanonicalJsonObject, CanonicalJsonValue, Raw},
-    state_res::{self, Event, RoomVersion, StateMap},
+    state_res::{self, RoomVersion, StateMap},
     uint, EventId, RoomAliasId, RoomId, RoomVersionId, ServerName, UserId,
 };
 use std::{
@@ -91,7 +91,7 @@ pub struct Rooms {
     pub(super) referencedevents: Arc<dyn Tree>,
 
     pub(super) pdu_cache: Mutex<LruCache<EventId, Arc<PduEvent>>>,
-    pub(super) auth_chain_cache: Mutex<LruCache<u64, HashSet<u64>>>,
+    pub(super) auth_chain_cache: Mutex<LruCache<Vec<u64>, HashSet<u64>>>,
     pub(super) shorteventid_cache: Mutex<LruCache<u64, EventId>>,
     pub(super) eventidshort_cache: Mutex<LruCache<EventId, u64>>,
     pub(super) statekeyshort_cache: Mutex<LruCache<(EventType, String), u64>>,
@@ -3166,7 +3166,7 @@ pub fn is_left(&self, user_id: &UserId, room_id: &RoomId) -> Result<bool> {
     }
 
     #[tracing::instrument(skip(self))]
-    pub fn auth_chain_cache(&self) -> std::sync::MutexGuard<'_, LruCache<u64, HashSet<u64>>> {
+    pub fn auth_chain_cache(&self) -> std::sync::MutexGuard<'_, LruCache<Vec<u64>, HashSet<u64>>> {
         self.auth_chain_cache.lock().unwrap()
     }
 }
diff --git a/src/server_server.rs b/src/server_server.rs
index e8ea48621856eb83f20537f230d111f661b630e6..cb89e40dc220ba4673cc8f91deae742e2bd64e0f 100644
--- a/src/server_server.rs
+++ b/src/server_server.rs
@@ -1976,27 +1976,39 @@ fn get_auth_chain(
 ) -> Result<impl Iterator<Item = EventId> + '_> {
     let mut full_auth_chain = HashSet::new();
 
-    let starting_events = starting_events
-        .iter()
-        .map(|id| {
-            db.rooms
-                .get_or_create_shorteventid(id, &db.globals)
-                .map(|s| (s, id))
-        })
-        .collect::<Result<Vec<_>>>()?;
+    const NUM_BUCKETS: usize = 100;
+
+    let mut buckets = vec![HashSet::new(); NUM_BUCKETS];
+
+    for id in starting_events {
+        let short = db.rooms.get_or_create_shorteventid(&id, &db.globals)?;
+        let bucket_id = (short % NUM_BUCKETS as u64) as usize;
+        buckets[bucket_id].insert((short, id));
+    }
 
     let mut cache = db.rooms.auth_chain_cache();
 
-    for (sevent_id, event_id) in starting_events {
-        if let Some(cached) = cache.get_mut(&sevent_id) {
+    for chunk in buckets {
+        let chunk_key = chunk.iter().map(|(short, _)| short).copied().collect();
+        if let Some(cached) = cache.get_mut(&chunk_key) {
             full_auth_chain.extend(cached.iter().cloned());
-        } else {
-            drop(cache);
-            let auth_chain = get_auth_chain_inner(&event_id, db)?;
-            cache = db.rooms.auth_chain_cache();
-            cache.insert(sevent_id, auth_chain.clone());
-            full_auth_chain.extend(auth_chain);
-        };
+            continue;
+        }
+
+        let mut chunk_cache = HashSet::new();
+        for (sevent_id, event_id) in chunk {
+            if let Some(cached) = cache.get_mut(&[sevent_id][..]) {
+                chunk_cache.extend(cached.iter().cloned());
+            } else {
+                drop(cache);
+                let auth_chain = get_auth_chain_inner(&event_id, db)?;
+                cache = db.rooms.auth_chain_cache();
+                cache.insert(vec![sevent_id], auth_chain.clone());
+                chunk_cache.extend(auth_chain);
+            };
+        }
+        cache.insert(chunk_key, chunk_cache.clone());
+        full_auth_chain.extend(chunk_cache);
     }
 
     drop(cache);