From 5173d0deb59a4bdaf03026f6894610e396ddbec4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20K=C3=B6sters?= <timo@koesters.xyz>
Date: Wed, 11 Aug 2021 21:14:22 +0200
Subject: [PATCH] improvement: cache for short event ids

---
 src/database.rs       |  1 +
 src/database/rooms.rs | 16 ++++++++++++++--
 src/server_server.rs  | 20 +++++++++-----------
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/database.rs b/src/database.rs
index 1bf9434f..7996057d 100644
--- a/src/database.rs
+++ b/src/database.rs
@@ -272,6 +272,7 @@ impl Database {
                 referencedevents: builder.open_tree("referencedevents")?,
                 pdu_cache: Mutex::new(LruCache::new(100_000)),
                 auth_chain_cache: Mutex::new(LruCache::new(100_000)),
+                shorteventid_cache: Mutex::new(LruCache::new(100_000)),
             },
             account_data: account_data::AccountData {
                 roomuserdataid_accountdata: builder.open_tree("roomuserdataid_accountdata")?,
diff --git a/src/database/rooms.rs b/src/database/rooms.rs
index c53fa9ea..246aa0ba 100644
--- a/src/database/rooms.rs
+++ b/src/database/rooms.rs
@@ -89,6 +89,7 @@ pub struct Rooms {
 
     pub(super) pdu_cache: Mutex<LruCache<EventId, Arc<PduEvent>>>,
     pub(super) auth_chain_cache: Mutex<LruCache<u64, HashSet<u64>>>,
+    pub(super) shorteventid_cache: Mutex<LruCache<u64, EventId>>,
 }
 
 impl Rooms {
@@ -447,17 +448,28 @@ impl Rooms {
     }
 
     pub fn get_eventid_from_short(&self, shorteventid: u64) -> Result<EventId> {
+        if let Some(id) = self.shorteventid_cache.lock().unwrap().get_mut(&shorteventid) {
+            return Ok(id.clone());
+        }
+
         let bytes = self
             .shorteventid_eventid
             .get(&shorteventid.to_be_bytes())?
             .ok_or_else(|| Error::bad_database("Shorteventid does not exist"))?;
 
-        EventId::try_from(
+        let event_id = EventId::try_from(
             utils::string_from_bytes(&bytes).map_err(|_| {
                 Error::bad_database("EventID in roomid_pduleaves is invalid unicode.")
             })?,
         )
-        .map_err(|_| Error::bad_database("EventId in roomid_pduleaves is invalid."))
+        .map_err(|_| Error::bad_database("EventId in roomid_pduleaves is invalid."))?;
+
+        self.shorteventid_cache
+            .lock()
+            .unwrap()
+            .insert(shorteventid, event_id.clone());
+
+        Ok(event_id)
     }
 
     /// Returns the full room state.
diff --git a/src/server_server.rs b/src/server_server.rs
index 23c80ee6..0b9a7e68 100644
--- a/src/server_server.rs
+++ b/src/server_server.rs
@@ -1311,7 +1311,7 @@ pub fn handle_incoming_pdu<'a>(
             for state in fork_states {
                 auth_chain_sets.push(
                     get_auth_chain(state.iter().map(|(_, id)| id.clone()).collect(), db)
-                        .map_err(|_| "Failed to load auth chain.".to_owned())?,
+                        .map_err(|_| "Failed to load auth chain.".to_owned())?.collect(),
                 );
             }
 
@@ -1756,15 +1756,15 @@ fn append_incoming_pdu(
     Ok(pdu_id)
 }
 
-fn get_auth_chain(starting_events: Vec<EventId>, db: &Database) -> Result<HashSet<EventId>> {
+fn get_auth_chain(starting_events: Vec<EventId>, db: &Database) -> Result<impl Iterator<Item = EventId> + '_> {
     let mut full_auth_chain = HashSet::new();
 
     let starting_events = starting_events
         .iter()
         .map(|id| {
-            (db.rooms
+            db.rooms
                 .get_or_create_shorteventid(id, &db.globals)
-                .map(|s| (s, id)))
+                .map(|s| (s, id))
         })
         .collect::<Result<Vec<_>>>()?;
 
@@ -1783,10 +1783,11 @@ fn get_auth_chain(starting_events: Vec<EventId>, db: &Database) -> Result<HashSe
         };
     }
 
-    full_auth_chain
+    drop(cache);
+
+    Ok(full_auth_chain
         .into_iter()
-        .map(|sid| db.rooms.get_eventid_from_short(sid))
-        .collect()
+        .filter_map(move |sid| db.rooms.get_eventid_from_short(sid).ok()))
 }
 
 fn get_auth_chain_recursive(
@@ -1909,7 +1910,6 @@ pub fn get_event_authorization_route(
 
     Ok(get_event_authorization::v1::Response {
         auth_chain: auth_chain_ids
-            .into_iter()
             .filter_map(|id| Some(db.rooms.get_pdu_json(&id).ok()??))
             .map(|event| PduEvent::convert_to_outgoing_federation_event(event))
             .collect(),
@@ -1953,7 +1953,6 @@ pub fn get_room_state_route(
 
     Ok(get_room_state::v1::Response {
         auth_chain: auth_chain_ids
-            .into_iter()
             .map(|id| {
                 Ok::<_, Error>(PduEvent::convert_to_outgoing_federation_event(
                     db.rooms.get_pdu_json(&id)?.unwrap(),
@@ -1996,7 +1995,7 @@ pub fn get_room_state_ids_route(
     let auth_chain_ids = get_auth_chain(vec![body.event_id.clone()], &db)?;
 
     Ok(get_room_state_ids::v1::Response {
-        auth_chain_ids: auth_chain_ids.into_iter().collect(),
+        auth_chain_ids: auth_chain_ids.collect(),
         pdu_ids,
     }
     .into())
@@ -2265,7 +2264,6 @@ pub async fn create_join_event_route(
     Ok(create_join_event::v2::Response {
         room_state: RoomState {
             auth_chain: auth_chain_ids
-                .iter()
                 .filter_map(|id| db.rooms.get_pdu_json(&id).ok().flatten())
                 .map(PduEvent::convert_to_outgoing_federation_event)
                 .collect(),