From c10ac7806e2cde04f344b641d01efa46d34f9985 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 12 Aug 2015 17:16:30 +0100 Subject: Explain why we're prefilling dict with Nones --- synapse/storage/state.py | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/synapse/storage/state.py b/synapse/storage/state.py index a3fc859b06..57e334cc3e 100644 --- a/synapse/storage/state.py +++ b/synapse/storage/state.py @@ -412,6 +412,10 @@ class StateStore(SQLBaseStore): for group, state_ids in group_state_dict.items(): if types: + # We delibrately put key -> None mappings into the cache to + # cache absence of the key, on the assumption that if we've + # explicitly asked for some types then we will probably ask + # for them again. state_dict = { key: None for key in types -- cgit 1.4.1