diff --git a/README.rst b/README.rst
index 12f0c0c51a64f40cd43103dd97fd14d9947ca037..4491b45181c9a1b2428ae50a5f92c14492bed9a8 100644
--- a/README.rst
+++ b/README.rst
@@ -359,7 +359,7 @@ https://www.archlinux.org/packages/community/any/matrix-synapse/, which should p
the necessary dependencies. If the default web client is to be served (enabled by default in
the generated config),
https://www.archlinux.org/packages/community/any/python2-matrix-angular-sdk/ will also need to
-be installed.
+be installed.
Alternatively, to install using pip a few changes may be needed as ArchLinux
defaults to python 3, but synapse currently assumes python 2.7 by default:
@@ -899,12 +899,9 @@ cache a lot of recent room data and metadata in RAM in order to speed up
common requests. We'll improve this in future, but for now the easiest
way to either reduce the RAM usage (at the risk of slowing things down)
is to set the almost-undocumented ``SYNAPSE_CACHE_FACTOR`` environment
-variable. Roughly speaking, a SYNAPSE_CACHE_FACTOR of 1.0 will max out
-at around 3-4GB of resident memory - this is what we currently run the
-matrix.org on. The default setting is currently 0.1, which is probably
-around a ~700MB footprint. You can dial it down further to 0.02 if
-desired, which targets roughly ~512MB. Conversely you can dial it up if
-you need performance for lots of users and have a box with a lot of RAM.
+variable. The default is 0.5, which can be decreased to reduce RAM usage
+in memory constrained enviroments, or increased if performance starts to
+degrade.
.. _`key_management`: https://matrix.org/docs/spec/server_server/unstable.html#retrieving-server-keys
diff --git a/synapse/state.py b/synapse/state.py
index 5b386e31830be80e6cfa9fec0427009a94c40277..390799fbd5815a158a2db831ad4127c0a2db7f0f 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -24,13 +24,13 @@ from synapse.api.constants import EventTypes
from synapse.api.errors import AuthError
from synapse.events.snapshot import EventContext
from synapse.util.async import Linearizer
+from synapse.util.caches import CACHE_SIZE_FACTOR
from collections import namedtuple
from frozendict import frozendict
import logging
import hashlib
-import os
logger = logging.getLogger(__name__)
@@ -38,9 +38,6 @@ logger = logging.getLogger(__name__)
KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.1))
-
-
SIZE_OF_CACHE = int(100000 * CACHE_SIZE_FACTOR)
EVICTION_TIMEOUT_SECONDS = 60 * 60
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 51730a88bf878582d4355f390d5bb69df0a93b1c..6f54036d67b37f0dc438e2c2879dcaf865f9fde2 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -16,6 +16,7 @@ import logging
from synapse.api.errors import StoreError
from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
+from synapse.util.caches import CACHE_SIZE_FACTOR
from synapse.util.caches.dictionary_cache import DictionaryCache
from synapse.util.caches.descriptors import Cache
from synapse.storage.engines import PostgresEngine
@@ -27,10 +28,6 @@ from twisted.internet import defer
import sys
import time
import threading
-import os
-
-
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.1))
logger = logging.getLogger(__name__)
diff --git a/synapse/storage/client_ips.py b/synapse/storage/client_ips.py
index 88a5eb232f46d695816acd0ac71570826074151f..fc468ea18532ae7f8b35fbe8b6a07adc64ab68a3 100644
--- a/synapse/storage/client_ips.py
+++ b/synapse/storage/client_ips.py
@@ -20,7 +20,8 @@ from twisted.internet import defer, reactor
from ._base import Cache
from . import background_updates
-import os
+from synapse.util.caches import CACHE_SIZE_FACTOR
+
logger = logging.getLogger(__name__)
@@ -30,9 +31,6 @@ logger = logging.getLogger(__name__)
LAST_SEEN_GRANULARITY = 120 * 1000
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.1))
-
-
class ClientIpStore(background_updates.BackgroundUpdateStore):
def __init__(self, hs):
self.client_ip_last_seen = Cache(
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index 4a83c46d98585920b8337bde07880ffd34f34c4a..4adae96681d4a1f0a6af01876b5745d694928604 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -16,7 +16,7 @@
import synapse.metrics
import os
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.1))
+CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.5))
metrics = synapse.metrics.get_metrics_for("synapse.util.caches")
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index cbdff86596894a1d22103ccb97813d7dfbcc5082..af65bfe7b8095a9bc3687fbf9109dcb4738b613d 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -16,6 +16,7 @@ import logging
from synapse.util.async import ObservableDeferred
from synapse.util import unwrapFirstError, logcontext
+from synapse.util.caches import CACHE_SIZE_FACTOR
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
@@ -25,7 +26,6 @@ from . import register_cache
from twisted.internet import defer
from collections import namedtuple
-import os
import functools
import inspect
import threading
@@ -37,9 +37,6 @@ logger = logging.getLogger(__name__)
_CacheSentinel = object()
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.1))
-
-
class CacheEntry(object):
__slots__ = [
"deferred", "sequence", "callbacks", "invalidated"
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index 609625b3229656e07cc2b148be2bae7d2d76d2b4..941d873ab8019280881951dcc33444f6b5370a6c 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -13,20 +13,16 @@
# See the License for the specific language governing permissions and
# limitations under the License.
-from synapse.util.caches import register_cache
+from synapse.util.caches import register_cache, CACHE_SIZE_FACTOR
from blist import sorteddict
import logging
-import os
logger = logging.getLogger(__name__)
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.1))
-
-
class StreamChangeCache(object):
"""Keeps track of the stream positions of the latest change in a set of entities.
diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py
index 281eb162547810e99fbcaae092fa409e4f28d925..3cfa21c9f86fc6bfaada8b2af25dc87bc75e1778 100644
--- a/tests/storage/test__base.py
+++ b/tests/storage/test__base.py
@@ -241,7 +241,7 @@ class CacheDecoratorTestCase(unittest.TestCase):
callcount2 = [0]
class A(object):
- @cached(max_entries=20) # HACK: This makes it 2 due to cache factor
+ @cached(max_entries=4) # HACK: This makes it 2 due to cache factor
def func(self, key):
callcount[0] += 1
return key