Minor cleanups

The playbook is not happy with the previous state of this patch so this commit hopefully fixes it

docs/maintenance-synapse.md

@@ -74,7 +74,7 @@ Synapse's presence feature which tracks which users are online and which are off
 
 If you have enough compute resources (CPU & RAM), you can make Synapse better use of them by [enabling load-balancing with workers](configuring-playbook-synapse.md#load-balancing-with-workers).
 
-Tuning Synapse's cache factor can help reduce RAM usage. [See the upstream documentation](https://github.com/element-hq/synapse#help-synapse-is-slow-and-eats-all-my-ram-cpu) for more information on what value to set the cache factor to. Use the variable `matrix_synapse_caches_global_factor` to set the cache factor.
+Tuning Synapse's cache factor can help reduce RAM usage. Use the variable `matrix_synapse_caches_global_factor` to set the cache factor.
 
 [Tuning your PostgreSQL database](maintenance-postgres.md#tuning-postgresql) could also improve Synapse performance. The playbook tunes the integrated Postgres database automatically, but based on your needs you may wish to adjust tuning variables manually. If you're using an [external Postgres database](configuring-playbook-external-postgres.md), you will aslo need to tune Postgres manually.
 

roles/custom/matrix-synapse/defaults/main.yml

@@ -546,8 +546,16 @@ matrix_synapse_event_cache_size: "100K"
 
 # Controls cache sizes for Synapse.
 # Raise this to increase cache sizes or lower it to potentially lower memory use.
-# To learn more, see: https://github.com/matrix-org/synapse/issues/3939
-matrix_synapse_caches_global_factor: 0.5
+# To learn more, see:
+# - https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#caching
+# - https://github.com/matrix-org/synapse/issues/3939
+matrix_synapse_caches_global_factor: 10
+matrix_synapse_caches_expire_caches: true
+matrix_synapse_caches_cache_entry_ttl: "30m"
+matrix_synapse_caches_sync_response_cache_duration: "2m"
+matrix_synapse_caches_autotuning_max_cache_memory_usage: "2048M"
+matrix_synapse_caches_autotuning_target_cache_memory_usage: "1024M"
+matrix_synapse_caches_autotuning_min_cache_ttl: "5m"
 
 # Controls whether Synapse will federate at all.
 # Disable this to completely isolate your server from the rest of the Matrix network.

roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -760,49 +760,48 @@ federation_domain_whitelist: {{ matrix_synapse_federation_domain_whitelist|to_js
 # The number of events to cache in memory. Not affected by
 # caches.global_factor.
 #
-event_cache_size: "{{ matrix_synapse_event_cache_size }}"
+event_cache_size: {{ matrix_synapse_event_cache_size | to_json }}
 
 caches:
-   # Controls the global cache factor, which is the default cache factor
-   # for all caches if a specific factor for that cache is not otherwise
-   # set.
-   #
-   # This can also be set by the "SYNAPSE_CACHE_FACTOR" environment
-   # variable. Setting by environment variable takes priority over
-   # setting through the config file.
-   #
-   # Defaults to 0.5, which will half the size of all caches.
-   #
-   global_factor: {{ matrix_synapse_caches_global_factor }}
-
-   # A dictionary of cache name to cache factor for that individual
-   # cache. Overrides the global cache factor for a given cache.
-   #
-   # These can also be set through environment variables comprised
-   # of "SYNAPSE_CACHE_FACTOR_" + the name of the cache in capital
-   # letters and underscores. Setting by environment variable
-   # takes priority over setting through the config file.
-   # Ex. SYNAPSE_CACHE_FACTOR_GET_USERS_WHO_SHARE_ROOM_WITH_USER=2.0
-   #
-   # Some caches have '*' and other characters that are not
-   # alphanumeric or underscores. These caches can be named with or
-   # without the special characters stripped. For example, to specify
-   # the cache factor for `*stateGroupCache*` via an environment
-   # variable would be `SYNAPSE_CACHE_FACTOR_STATEGROUPCACHE=2.0`.
-   #
-   per_cache_factors:
-     #get_users_who_share_room_with_user: 2.0
+  # Controls the global cache factor, which is the default cache factor
+  # for all caches if a specific factor for that cache is not otherwise
+  # set.
+  #
+  # This can also be set by the "SYNAPSE_CACHE_FACTOR" environment
+  # variable. Setting by environment variable takes priority over
+  # setting through the config file.
+  #
+  # Defaults to 0.5, which will half the size of all caches.
+  #
+  global_factor: {{ matrix_synapse_caches_global_factor | to_json }}
+  # A dictionary of cache name to cache factor for that individual
+  # cache. Overrides the global cache factor for a given cache.
+  #
+  # These can also be set through environment variables comprised
+  # of "SYNAPSE_CACHE_FACTOR_" + the name of the cache in capital
+  # letters and underscores. Setting by environment variable
+  # takes priority over setting through the config file.
+  # Ex. SYNAPSE_CACHE_FACTOR_GET_USERS_WHO_SHARE_ROOM_WITH_USER=2.0
+  #
+  # Some caches have '*' and other characters that are not
+  # alphanumeric or underscores. These caches can be named with or
+  # without the special characters stripped. For example, to specify
+  # the cache factor for `*stateGroupCache*` via an environment
+  # variable would be `SYNAPSE_CACHE_FACTOR_STATEGROUPCACHE=2.0`.
+  #
+  per_cache_factors:
+    #get_users_who_share_room_with_user: 2.0
 
   # Controls whether cache entries are evicted after a specified time
   # period. Defaults to true. Uncomment to disable this feature.
   #
-  #expire_caches: false
+  expire_caches: {{ matrix_synapse_caches_expire_caches | to_json }}
 
   # If expire_caches is enabled, this flag controls how long an entry can
   # be in a cache without having been accessed before being evicted.
   # Defaults to 30m. Uncomment to set a different time to live for cache entries.
   #
-  #cache_entry_ttl: 30m
+  cache_entry_ttl: {{ matrix_synapse_caches_cache_entry_ttl | to_json }}
 
   # Controls how long the results of a /sync request are cached for after
   # a successful response is returned. A higher duration can help clients with
@@ -811,7 +810,16 @@ caches:
   # By default, this is zero, which means that sync responses are not cached
   # at all.
   #
-  #sync_response_cache_duration: 2m
+  sync_response_cache_duration: {{ matrix_synapse_caches_sync_response_cache_duration | to_json }}
+
+  #FIX ME add documentation notes about these settings or remove this note.
+  # Check upstream https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#caching
+  # for information for now
+  #
+  cache_autotuning:
+    max_cache_memory_usage: {{ matrix_synapse_caches_autotuning_max_cache_memory_usage | to_json }}
+    target_cache_memory_usage: {{ matrix_synapse_caches_autotuning_target_cache_memory_usage | to_json }}
+    min_cache_ttl: {{ matrix_synapse_caches_autotuning_min_cache_ttl | to_json }}
 
 
 ## Database ##