From b616a8717be7e71be5494d65e45e99713068ac1b Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 19 Mar 2019 16:04:49 +0000
Subject: [PATCH 1/2] Add note on tuning postgres

---
 docs/postgres.rst | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/docs/postgres.rst b/docs/postgres.rst
index 237754229..f7ebbed0c 100644
--- a/docs/postgres.rst
+++ b/docs/postgres.rst
@@ -49,6 +49,24 @@ As with Debian/Ubuntu, postgres support depends on the postgres python connector
     export PATH=/usr/pgsql-9.4/bin/:$PATH
     pip install psycopg2
 
+Tuning Postgres
+===============
+
+The default settings should be fine for most deployments. For larger scale
+deployments tuning some of the settings is recommended, details of which can be
+found at https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server.
+
+In particular, we've found tuning the following values helpful for performance:
+
+- ``shared_buffers``
+- ``effective_cache_size``
+- ``work_mem``
+- ``maintenance_work_mem``
+- ``autovacuum_work_mem``
+
+Note that the appropriate values for those fields depend on the amount of free
+memory the database host has available.
+
 Synapse config
 ==============
 
@@ -129,8 +147,8 @@ Once that has completed, change the synapse config to point at the PostgreSQL
 database configuration file ``homeserver-postgres.yaml``::
 
     ./synctl stop
-    mv homeserver.yaml homeserver-old-sqlite.yaml 
-    mv homeserver-postgres.yaml homeserver.yaml 
+    mv homeserver.yaml homeserver-old-sqlite.yaml
+    mv homeserver-postgres.yaml homeserver.yaml
     ./synctl start
 
 Synapse should now be running against PostgreSQL.

From 38ae23d5c2d4f2934724775d7d0f77f16cb91735 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 19 Mar 2019 16:07:07 +0000
Subject: [PATCH 2/2] Newsfile

---
 changelog.d/4895.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/4895.misc

diff --git a/changelog.d/4895.misc b/changelog.d/4895.misc
new file mode 100644
index 000000000..81a326153
--- /dev/null
+++ b/changelog.d/4895.misc
@@ -0,0 +1 @@
+Add some notes about tuning postgres for larger deployments.