diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index 080388958f..2987c38a2d 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -15,6 +15,7 @@
from synapse.util.caches import register_cache
+from collections import OrderedDict
import logging
@@ -23,7 +24,7 @@ logger = logging.getLogger(__name__)
class ExpiringCache(object):
def __init__(self, cache_name, clock, max_len=0, expiry_ms=0,
- reset_expiry_on_get=False):
+ reset_expiry_on_get=False, iterable=False):
"""
Args:
cache_name (str): Name of this cache, used for logging.
@@ -36,6 +37,8 @@ class ExpiringCache(object):
evicted based on time.
reset_expiry_on_get (bool): If true, will reset the expiry time for
an item on access. Defaults to False.
+ iterable (bool): If true, the size is calculated by summing the
+ sizes of all entries, rather than the number of entries.
"""
self._cache_name = cache_name
@@ -47,9 +50,13 @@ class ExpiringCache(object):
self._reset_expiry_on_get = reset_expiry_on_get
- self._cache = {}
+ self._cache = OrderedDict()
- self.metrics = register_cache(cache_name, self._cache)
+ self.metrics = register_cache(cache_name, self)
+
+ self.iterable = iterable
+
+ self._size_estimate = 0
def start(self):
if not self._expiry_ms:
@@ -65,15 +72,14 @@ class ExpiringCache(object):
now = self._clock.time_msec()
self._cache[key] = _CacheEntry(now, value)
- # Evict if there are now too many items
- if self._max_len and len(self._cache.keys()) > self._max_len:
- sorted_entries = sorted(
- self._cache.items(),
- key=lambda item: item[1].time,
- )
+ if self.iterable:
+ self._size_estimate += len(value)
- for k, _ in sorted_entries[self._max_len:]:
- self._cache.pop(k)
+ # Evict if there are now too many items
+ while self._max_len and len(self) > self._max_len:
+ _key, value = self._cache.popitem(last=False)
+ if self.iterable:
+ self._size_estimate -= len(value.value)
def __getitem__(self, key):
try:
@@ -99,7 +105,7 @@ class ExpiringCache(object):
# zero expiry time means don't expire. This should never get called
# since we have this check in start too.
return
- begin_length = len(self._cache)
+ begin_length = len(self)
now = self._clock.time_msec()
@@ -110,15 +116,20 @@ class ExpiringCache(object):
keys_to_delete.add(key)
for k in keys_to_delete:
- self._cache.pop(k)
+ value = self._cache.pop(k)
+ if self.iterable:
+ self._size_estimate -= len(value.value)
logger.debug(
"[%s] _prune_cache before: %d, after len: %d",
- self._cache_name, begin_length, len(self._cache)
+ self._cache_name, begin_length, len(self)
)
def __len__(self):
- return len(self._cache)
+ if self.iterable:
+ return self._size_estimate
+ else:
+ return len(self._cache)
class _CacheEntry(object):
|
