1 files changed, 11 insertions, 4 deletions
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index f088dd430e..1c5a982094 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -154,14 +154,21 @@ class LruCache(object):
def cache_set(key, value, callbacks=[]):
node = cache.get(key, None)
if node is not None:
- if value != node.value:
+ # We sometimes store large objects, e.g. dicts, which cause
+ # the inequality check to take a long time. So let's only do
+ # the check if we have some callbacks to call.
+ if node.callbacks and value != node.value:
for cb in node.callbacks:
cb()
node.callbacks.clear()
- if size_callback:
- cached_cache_len[0] -= size_callback(node.value)
- cached_cache_len[0] += size_callback(value)
+ # We don't bother to protect this by value != node.value as
+ # generally size_callback will be cheap compared with equality
+ # checks. (For example, taking the size of two dicts is quicker
+ # than comparing them for equality.)
+ if size_callback:
+ cached_cache_len[0] -= size_callback(node.value)
+ cached_cache_len[0] += size_callback(value)
node.callbacks.update(callbacks)
|
