diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index af65bfe7b8..f8a07df6b8 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -1,5 +1,6 @@
# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
@@ -12,25 +13,26 @@
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
+import functools
+import inspect
import logging
+import threading
+from collections import namedtuple
+
+import six
+from six import itervalues, string_types
+
+from twisted.internet import defer
+from synapse.util import logcontext, unwrapFirstError
from synapse.util.async import ObservableDeferred
-from synapse.util import unwrapFirstError, logcontext
-from synapse.util.caches import CACHE_SIZE_FACTOR
+from synapse.util.caches import get_cache_factor_for
from synapse.util.caches.lrucache import LruCache
from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
from synapse.util.stringutils import to_ascii
from . import register_cache
-from twisted.internet import defer
-from collections import namedtuple
-
-import functools
-import inspect
-import threading
-
-
logger = logging.getLogger(__name__)
@@ -39,12 +41,11 @@ _CacheSentinel = object()
class CacheEntry(object):
__slots__ = [
- "deferred", "sequence", "callbacks", "invalidated"
+ "deferred", "callbacks", "invalidated"
]
- def __init__(self, deferred, sequence, callbacks):
+ def __init__(self, deferred, callbacks):
self.deferred = deferred
- self.sequence = sequence
self.callbacks = set(callbacks)
self.invalidated = False
@@ -62,7 +63,6 @@ class Cache(object):
"max_entries",
"name",
"keylen",
- "sequence",
"thread",
"metrics",
"_pending_deferred_cache",
@@ -75,13 +75,16 @@ class Cache(object):
self.cache = LruCache(
max_size=max_entries, keylen=keylen, cache_type=cache_type,
size_callback=(lambda d: len(d)) if iterable else None,
+ evicted_callback=self._on_evicted,
)
self.name = name
self.keylen = keylen
- self.sequence = 0
self.thread = None
- self.metrics = register_cache(name, self.cache)
+ self.metrics = register_cache("cache", name, self.cache)
+
+ def _on_evicted(self, evicted_count):
+ self.metrics.inc_evictions(evicted_count)
def check_thread(self):
expected_thread = self.thread
@@ -109,11 +112,10 @@ class Cache(object):
callbacks = [callback] if callback else []
val = self._pending_deferred_cache.get(key, _CacheSentinel)
if val is not _CacheSentinel:
- if val.sequence == self.sequence:
- val.callbacks.update(callbacks)
- if update_metrics:
- self.metrics.inc_hits()
- return val.deferred
+ val.callbacks.update(callbacks)
+ if update_metrics:
+ self.metrics.inc_hits()
+ return val.deferred
val = self.cache.get(key, _CacheSentinel, callbacks=callbacks)
if val is not _CacheSentinel:
@@ -133,12 +135,9 @@ class Cache(object):
self.check_thread()
entry = CacheEntry(
deferred=value,
- sequence=self.sequence,
callbacks=callbacks,
)
- entry.callbacks.update(callbacks)
-
existing_entry = self._pending_deferred_cache.pop(key, None)
if existing_entry:
existing_entry.invalidate()
@@ -146,13 +145,25 @@ class Cache(object):
self._pending_deferred_cache[key] = entry
def shuffle(result):
- if self.sequence == entry.sequence:
- existing_entry = self._pending_deferred_cache.pop(key, None)
- if existing_entry is entry:
- self.cache.set(key, result, entry.callbacks)
- else:
- entry.invalidate()
+ existing_entry = self._pending_deferred_cache.pop(key, None)
+ if existing_entry is entry:
+ self.cache.set(key, result, entry.callbacks)
else:
+ # oops, the _pending_deferred_cache has been updated since
+ # we started our query, so we are out of date.
+ #
+ # Better put back whatever we took out. (We do it this way
+ # round, rather than peeking into the _pending_deferred_cache
+ # and then removing on a match, to make the common case faster)
+ if existing_entry is not None:
+ self._pending_deferred_cache[key] = existing_entry
+
+ # we're not going to put this entry into the cache, so need
+ # to make sure that the invalidation callbacks are called.
+ # That was probably done when _pending_deferred_cache was
+ # updated, but it's possible that `set` was called without
+ # `invalidate` being previously called, in which case it may
+ # not have been. Either way, let's double-check now.
entry.invalidate()
return result
@@ -164,25 +175,29 @@ class Cache(object):
def invalidate(self, key):
self.check_thread()
+ self.cache.pop(key, None)
- # Increment the sequence number so that any SELECT statements that
- # raced with the INSERT don't update the cache (SYN-369)
- self.sequence += 1
+ # if we have a pending lookup for this key, remove it from the
+ # _pending_deferred_cache, which will (a) stop it being returned
+ # for future queries and (b) stop it being persisted as a proper entry
+ # in self.cache.
entry = self._pending_deferred_cache.pop(key, None)
+
+ # run the invalidation callbacks now, rather than waiting for the
+ # deferred to resolve.
if entry:
entry.invalidate()
- self.cache.pop(key, None)
-
def invalidate_many(self, key):
self.check_thread()
if not isinstance(key, tuple):
raise TypeError(
"The cache key must be a tuple not %r" % (type(key),)
)
- self.sequence += 1
self.cache.del_multi(key)
+ # if we have a pending lookup for this key, remove it from the
+ # _pending_deferred_cache, as above
entry_dict = self._pending_deferred_cache.pop(key, None)
if entry_dict is not None:
for entry in iterate_tree_cache_entry(entry_dict):
@@ -190,8 +205,10 @@ class Cache(object):
def invalidate_all(self):
self.check_thread()
- self.sequence += 1
self.cache.clear()
+ for entry in itervalues(self._pending_deferred_cache):
+ entry.invalidate()
+ self._pending_deferred_cache.clear()
class _CacheDescriptorBase(object):
@@ -294,7 +311,7 @@ class CacheDescriptor(_CacheDescriptorBase):
orig, num_args=num_args, inlineCallbacks=inlineCallbacks,
cache_context=cache_context)
- max_entries = int(max_entries * CACHE_SIZE_FACTOR)
+ max_entries = int(max_entries * get_cache_factor_for(orig.__name__))
self.max_entries = max_entries
self.tree = tree
@@ -376,9 +393,10 @@ class CacheDescriptor(_CacheDescriptorBase):
ret.addErrback(onErr)
- # If our cache_key is a string, try to convert to ascii to save
- # a bit of space in large caches
- if isinstance(cache_key, basestring):
+ # If our cache_key is a string on py2, try to convert to ascii
+ # to save a bit of space in large caches. Py3 does this
+ # internally automatically.
+ if six.PY2 and isinstance(cache_key, string_types):
cache_key = to_ascii(cache_key)
result_d = ObservableDeferred(ret, consumeErrors=True)
@@ -549,7 +567,7 @@ class CacheListDescriptor(_CacheDescriptorBase):
return results
return logcontext.make_deferred_yieldable(defer.gatherResults(
- cached_defers.values(),
+ list(cached_defers.values()),
consumeErrors=True,
).addCallback(update_results_dict).addErrback(
unwrapFirstError
|
