Use dictionary cache to do group -> state fetching

1 files changed, 26 insertions, 13 deletions

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 7b76ee3b73..803b9d599d 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -18,6 +18,7 @@ from synapse.api.errors import StoreError
 from synapse.util.logutils import log_function
 from synapse.util.logcontext import preserve_context_over_fn, LoggingContext
 from synapse.util.lrucache import LruCache
+from synapse.util.dictionary_cache import DictionaryCache
 import synapse.metrics
 
 from util.id_generators import IdGenerator, StreamIdGenerator
@@ -87,23 +88,33 @@ class Cache(object):
                 )
 
     def get(self, *keyargs):
-        if len(keyargs) != self.keylen:
-            raise ValueError("Expected a key to have %d items", self.keylen)
+        try:
+            if len(keyargs) != self.keylen:
+                raise ValueError("Expected a key to have %d items", self.keylen)
 
-        val = self.cache.get(keyargs, self.sentinel)
-        if val is not self.sentinel:
-            cache_counter.inc_hits(self.name)
-            return val
+            val = self.cache.get(keyargs, self.sentinel)
+            if val is not self.sentinel:
+                cache_counter.inc_hits(self.name)
+                return val
 
-        cache_counter.inc_misses(self.name)
-        raise KeyError()
+            cache_counter.inc_misses(self.name)
+            raise KeyError()
+        except KeyError:
+            raise
+        except:
+            logger.exception("Cache.get failed for %s" % (self.name,))
+            raise
 
     def update(self, sequence, *args):
-        self.check_thread()
-        if self.sequence == sequence:
-            # Only update the cache if the caches sequence number matches the
-            # number that the cache had before the SELECT was started (SYN-369)
-            self.prefill(*args)
+        try:
+            self.check_thread()
+            if self.sequence == sequence:
+                # Only update the cache if the caches sequence number matches the
+                # number that the cache had before the SELECT was started (SYN-369)
+                self.prefill(*args)
+        except:
+            logger.exception("Cache.update failed for %s" % (self.name,))
+            raise
 
     def prefill(self, *args):  # because I can't  *keyargs, value
         keyargs = args[:-1]
@@ -327,6 +338,8 @@ class SQLBaseStore(object):
         self._get_event_cache = Cache("*getEvent*", keylen=3, lru=True,
                                       max_entries=hs.config.event_cache_size)
 
+        self._state_group_cache = DictionaryCache("*stateGroupCache*", 100000)
+
         self._event_fetch_lock = threading.Condition()
         self._event_fetch_list = []
         self._event_fetch_ongoing = 0