diff options
Diffstat (limited to 'synapse/util')
| -rw-r--r-- | synapse/util/caches/lrucache.py | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py index 6e8c1e84ac..a1b4f5b6a7 100644 --- a/synapse/util/caches/lrucache.py +++ b/synapse/util/caches/lrucache.py @@ -35,6 +35,7 @@ from typing import ( Iterable, List, Optional, + Set, Tuple, Type, TypeVar, @@ -386,6 +387,7 @@ class LruCache(Generic[KT, VT]): apply_cache_factor_from_config: bool = True, clock: Optional[Clock] = None, prune_unread_entries: bool = True, + extra_index_cb: Optional[Callable[[KT, VT], KT]] = None, ): """ Args: @@ -416,6 +418,20 @@ class LruCache(Generic[KT, VT]): prune_unread_entries: If True, cache entries that haven't been read recently will be evicted from the cache in the background. Set to False to opt-out of this behaviour. + + extra_index_cb: If provided, the cache keeps a second index from a + (different) key to a cache entry based on the return value of + the callback. This can then be used to invalidate entries based + on the second type of key. + + For example, for the event cache this would be a callback that + maps an event to its room ID, allowing invalidation of all + events in a given room. + + Note: Though the two types of key have the same type, they are + in different namespaces. + + Note: The new key does not have to be unique. """ # Default `clock` to something sensible. Note that we rename it to # `real_clock` so that mypy doesn't think its still `Optional`. @@ -463,6 +479,8 @@ class LruCache(Generic[KT, VT]): lock = threading.Lock() + extra_index: Dict[KT, Set[KT]] = {} + def evict() -> None: while cache_len() > self.max_size: # Get the last node in the list (i.e. the oldest node). @@ -521,6 +539,11 @@ class LruCache(Generic[KT, VT]): if size_callback: cached_cache_len[0] += size_callback(node.value) + if extra_index_cb: + index_key = extra_index_cb(node.key, node.value) + mapped_keys = extra_index.setdefault(index_key, set()) + mapped_keys.add(node.key) + if caches.TRACK_MEMORY_USAGE and metrics: metrics.inc_memory_usage(node.memory) @@ -537,6 +560,14 @@ class LruCache(Generic[KT, VT]): node.run_and_clear_callbacks() + if extra_index_cb: + index_key = extra_index_cb(node.key, node.value) + mapped_keys = extra_index.get(index_key) + if mapped_keys is not None: + mapped_keys.discard(node.key) + if not mapped_keys: + extra_index.pop(index_key, None) + if caches.TRACK_MEMORY_USAGE and metrics: metrics.dec_memory_usage(node.memory) @@ -748,6 +779,8 @@ class LruCache(Generic[KT, VT]): if size_callback: cached_cache_len[0] = 0 + extra_index.clear() + if caches.TRACK_MEMORY_USAGE and metrics: metrics.clear_memory_usage() @@ -755,6 +788,28 @@ class LruCache(Generic[KT, VT]): def cache_contains(key: KT) -> bool: return key in cache + @synchronized + def cache_invalidate_on_extra_index(index_key: KT) -> None: + """Invalidates all entries that match the given extra index key. + + This can only be called when `extra_index_cb` was specified. + """ + + assert extra_index_cb is not None + + keys = extra_index.pop(index_key, None) + if not keys: + return + + for key in keys: + node = cache.pop(key, None) + if not node: + continue + + evicted_len = delete_node(node) + if metrics: + metrics.inc_evictions(EvictionReason.invalidation, evicted_len) + # make sure that we clear out any excess entries after we get resized. self._on_resize = evict @@ -771,6 +826,7 @@ class LruCache(Generic[KT, VT]): self.len = synchronized(cache_len) self.contains = cache_contains self.clear = cache_clear + self.invalidate_on_extra_index = cache_invalidate_on_extra_index def __getitem__(self, key: KT) -> VT: result = self.get(key, _Sentinel.sentinel) @@ -864,6 +920,9 @@ class AsyncLruCache(Generic[KT, VT]): # This method should invalidate any external cache and then invalidate the LruCache. return self._lru_cache.invalidate(key) + def invalidate_on_extra_index_local(self, index_key: KT) -> None: + self._lru_cache.invalidate_on_extra_index(index_key) + def invalidate_local(self, key: KT) -> None: """Remove an entry from the local cache |