Add basic dictionary cache

This commit is contained in:
Erik Johnston 2015-08-04 15:56:56 +01:00
parent 2e35a733cc
commit e7768e77f5
2 changed files with 195 additions and 0 deletions

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# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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.
from synapse.util.lrucache import LruCache
from collections import namedtuple
import threading
DictionaryEntry = namedtuple("DictionaryEntry", ("full", "value"))
class DictionaryCache(object):
def __init__(self, name, max_entries=1000):
self.cache = LruCache(max_size=max_entries)
self.name = name
self.sequence = 0
self.thread = None
# caches_by_name[name] = self.cache
class Sentinel(object):
__slots__ = []
self.sentinel = Sentinel()
def check_thread(self):
expected_thread = self.thread
if expected_thread is None:
self.thread = threading.current_thread()
else:
if expected_thread is not threading.current_thread():
raise ValueError(
"Cache objects can only be accessed from the main thread"
)
def get(self, key, dict_keys=None):
entry = self.cache.get(key, self.sentinel)
if entry is not self.sentinel:
# cache_counter.inc_hits(self.name)
if dict_keys is None:
return DictionaryEntry(entry.full, dict(entry.value))
else:
return DictionaryEntry(entry.full, {
k: entry.value[k]
for k in dict_keys
if k in entry.value
})
# cache_counter.inc_misses(self.name)
return DictionaryEntry(False, {})
def invalidate(self, key):
self.check_thread()
# Increment the sequence number so that any SELECT statements that
# raced with the INSERT don't update the cache (SYN-369)
self.sequence += 1
self.cache.pop(key, None)
def invalidate_all(self):
self.check_thread()
self.sequence += 1
self.cache.clear()
def update(self, sequence, key, value, full=False):
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)
if full:
self._insert(key, value)
else:
self._update_or_insert(key, value)
def _update_or_insert(self, key, value):
entry = self.cache.setdefault(key, DictionaryEntry(False, {}))
entry.value.update(value)
def _insert(self, key, value):
self.cache[key] = DictionaryEntry(True, value)

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# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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.
from twisted.internet import defer
from tests import unittest
from synapse.storage.util.caches import DictionaryCache
class DictCacheTestCase(unittest.TestCase):
def setUp(self):
self.cache = DictionaryCache("foobar")
def test_simple_cache_hit_full(self):
key = "test_simple_cache_hit_full"
v = self.cache.get(key)
self.assertEqual((False, {}), v)
seq = self.cache.sequence
test_value = {"test": "test_simple_cache_hit_full"}
self.cache.update(seq, key, test_value, full=True)
c = self.cache.get(key)
self.assertEqual(test_value, c.value)
def test_simple_cache_hit_partial(self):
key = "test_simple_cache_hit_partial"
seq = self.cache.sequence
test_value = {
"test": "test_simple_cache_hit_partial"
}
self.cache.update(seq, key, test_value, full=True)
c = self.cache.get(key, ["test"])
self.assertEqual(test_value, c.value)
def test_simple_cache_miss_partial(self):
key = "test_simple_cache_miss_partial"
seq = self.cache.sequence
test_value = {
"test": "test_simple_cache_miss_partial"
}
self.cache.update(seq, key, test_value, full=True)
c = self.cache.get(key, ["test2"])
self.assertEqual({}, c.value)
def test_simple_cache_hit_miss_partial(self):
key = "test_simple_cache_hit_miss_partial"
seq = self.cache.sequence
test_value = {
"test": "test_simple_cache_hit_miss_partial",
"test2": "test_simple_cache_hit_miss_partial2",
"test3": "test_simple_cache_hit_miss_partial3",
}
self.cache.update(seq, key, test_value, full=True)
c = self.cache.get(key, ["test2"])
self.assertEqual({"test2": "test_simple_cache_hit_miss_partial2"}, c.value)
def test_multi_insert(self):
key = "test_simple_cache_hit_miss_partial"
seq = self.cache.sequence
test_value_1 = {
"test": "test_simple_cache_hit_miss_partial",
}
self.cache.update(seq, key, test_value_1, full=False)
seq = self.cache.sequence
test_value_2 = {
"test2": "test_simple_cache_hit_miss_partial2",
}
self.cache.update(seq, key, test_value_2, full=False)
c = self.cache.get(key)
self.assertEqual(
{
"test": "test_simple_cache_hit_miss_partial",
"test2": "test_simple_cache_hit_miss_partial2",
},
c.value
)