Replace DeferredCache with LruCache where possible (#8563)

Most of these uses don't need a full-blown DeferredCache; LruCache is lighter and more appropriate.

synapse/storage/databases/main/client_ips.py

@@ -19,7 +19,7 @@ from typing import Dict, Optional, Tuple
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.database import DatabasePool, make_tuple_comparison_clause
-from synapse.util.caches.deferred_cache import DeferredCache
+from synapse.util.caches.lrucache import LruCache
 
 logger = logging.getLogger(__name__)
 
@@ -410,8 +410,8 @@ class ClientIpWorkerStore(ClientIpBackgroundUpdateStore):
 class ClientIpStore(ClientIpWorkerStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
 
-        self.client_ip_last_seen = DeferredCache(
-            name="client_ip_last_seen", keylen=4, max_entries=50000
+        self.client_ip_last_seen = LruCache(
+            cache_name="client_ip_last_seen", keylen=4, max_size=50000
         )
 
         super().__init__(database, db_conn, hs)
@@ -442,7 +442,7 @@ class ClientIpStore(ClientIpWorkerStore):
         if last_seen is not None and (now - last_seen) < LAST_SEEN_GRANULARITY:
             return
 
-        self.client_ip_last_seen.prefill(key, now)
+        self.client_ip_last_seen.set(key, now)
 
         self._batch_row_update[key] = (user_agent, device_id, now)
 

synapse/storage/databases/main/devices.py

@@ -34,8 +34,8 @@ from synapse.storage.database import (
 )
 from synapse.types import Collection, JsonDict, get_verify_key_from_cross_signing_key
 from synapse.util import json_decoder, json_encoder
-from synapse.util.caches.deferred_cache import DeferredCache
 from synapse.util.caches.descriptors import cached, cachedList
+from synapse.util.caches.lrucache import LruCache
 from synapse.util.iterutils import batch_iter
 from synapse.util.stringutils import shortstr
 
@@ -1005,8 +1005,8 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
 
         # Map of (user_id, device_id) -> bool. If there is an entry that implies
         # the device exists.
-        self.device_id_exists_cache = DeferredCache(
-            name="device_id_exists", keylen=2, max_entries=10000
+        self.device_id_exists_cache = LruCache(
+            cache_name="device_id_exists", keylen=2, max_size=10000
         )
 
     async def store_device(
@@ -1052,7 +1052,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
                 )
                 if hidden:
                     raise StoreError(400, "The device ID is in use", Codes.FORBIDDEN)
-            self.device_id_exists_cache.prefill(key, True)
+            self.device_id_exists_cache.set(key, True)
             return inserted
         except StoreError:
             raise

synapse/storage/databases/main/events.py

@@ -1051,9 +1051,7 @@ class PersistEventsStore:
 
         def prefill():
             for cache_entry in to_prefill:
-                self.store._get_event_cache.prefill(
-                    (cache_entry[0].event_id,), cache_entry
-                )
+                self.store._get_event_cache.set((cache_entry[0].event_id,), cache_entry)
 
         txn.call_after(prefill)
 

synapse/storage/databases/main/events_worker.py

@@ -42,8 +42,8 @@ from synapse.storage.database import DatabasePool
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.util.id_generators import MultiWriterIdGenerator, StreamIdGenerator
 from synapse.types import Collection, get_domain_from_id
-from synapse.util.caches.deferred_cache import DeferredCache
 from synapse.util.caches.descriptors import cached
+from synapse.util.caches.lrucache import LruCache
 from synapse.util.iterutils import batch_iter
 from synapse.util.metrics import Measure
 
@@ -146,11 +146,10 @@ class EventsWorkerStore(SQLBaseStore):
                 self._cleanup_old_transaction_ids,
             )
 
-        self._get_event_cache = DeferredCache(
-            "*getEvent*",
+        self._get_event_cache = LruCache(
+            cache_name="*getEvent*",
             keylen=3,
-            max_entries=hs.config.caches.event_cache_size,
-            apply_cache_factor_from_config=False,
+            max_size=hs.config.caches.event_cache_size,
         )
 
         self._event_fetch_lock = threading.Condition()
@@ -749,7 +748,7 @@ class EventsWorkerStore(SQLBaseStore):
                 event=original_ev, redacted_event=redacted_event
             )
 
-            self._get_event_cache.prefill((event_id,), cache_entry)
+            self._get_event_cache.set((event_id,), cache_entry)
             result_map[event_id] = cache_entry
 
         return result_map