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https://mau.dev/maunium/synapse.git
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f85b6ca494
Instead of calculating the size of the cache repeatedly, which can take a long time now that it can use a callback, instead cache the size and update that on insertion and deletion. This requires changing the cache descriptors to have two caches, one for pending deferreds and the other for the actual values. There's no reason to evict from the pending deferreds as they won't take up any more memory.
106 lines
3.4 KiB
Python
106 lines
3.4 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2015, 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from synapse.util.caches.lrucache import LruCache
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from collections import namedtuple
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from . import register_cache
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import threading
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import logging
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logger = logging.getLogger(__name__)
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class DictionaryEntry(namedtuple("DictionaryEntry", ("full", "value"))):
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def __len__(self):
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return len(self.value)
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class DictionaryCache(object):
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"""Caches key -> dictionary lookups, supporting caching partial dicts, i.e.
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fetching a subset of dictionary keys for a particular key.
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"""
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def __init__(self, name, max_entries=1000):
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self.cache = LruCache(max_size=max_entries, size_callback=len)
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self.name = name
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self.sequence = 0
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self.thread = None
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# caches_by_name[name] = self.cache
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class Sentinel(object):
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__slots__ = []
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self.sentinel = Sentinel()
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self.metrics = register_cache(name, self.cache)
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def check_thread(self):
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expected_thread = self.thread
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if expected_thread is None:
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self.thread = threading.current_thread()
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else:
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if expected_thread is not threading.current_thread():
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raise ValueError(
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"Cache objects can only be accessed from the main thread"
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)
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def get(self, key, dict_keys=None):
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entry = self.cache.get(key, self.sentinel)
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if entry is not self.sentinel:
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self.metrics.inc_hits()
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if dict_keys is None:
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return DictionaryEntry(entry.full, dict(entry.value))
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else:
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return DictionaryEntry(entry.full, {
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k: entry.value[k]
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for k in dict_keys
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if k in entry.value
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})
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self.metrics.inc_misses()
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return DictionaryEntry(False, {})
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def invalidate(self, key):
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self.check_thread()
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# Increment the sequence number so that any SELECT statements that
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# raced with the INSERT don't update the cache (SYN-369)
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self.sequence += 1
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self.cache.pop(key, None)
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def invalidate_all(self):
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self.check_thread()
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self.sequence += 1
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self.cache.clear()
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def update(self, sequence, key, value, full=False):
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self.check_thread()
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if self.sequence == sequence:
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# Only update the cache if the caches sequence number matches the
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# number that the cache had before the SELECT was started (SYN-369)
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if full:
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self._insert(key, value)
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else:
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self._update_or_insert(key, value)
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def _update_or_insert(self, key, value):
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entry = self.cache.setdefault(key, DictionaryEntry(False, {}))
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entry.value.update(value)
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def _insert(self, key, value):
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self.cache[key] = DictionaryEntry(True, value)
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