Request partial joins by default (#14905)

* Request partial joins by default

This is a little sloppy, but we are trying to gain confidence in faster
joins in the upcoming RC.

Admins can still opt out by adding the following to their Synapse
config:

```yaml
experimental:
    faster_joins: false
```

We may revert this change before the release proper, depending on how
testing in the wild goes.

* Changelog

* Try to fix the backfill test failures

* Upgrade notes

* Postgres compat?

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/config/experimental.py b/synapse/config/experimental.py

index 89586db763..2590c88cde 100644
--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@@ -84,7 +84,7 @@ class ExperimentalConfig(Config):
         # experimental support for faster joins over federation
         # (MSC2775, MSC3706, MSC3895)
         # requires a target server that can provide a partial join response (MSC3706)
-        self.faster_joins_enabled: bool = experimental.get("faster_joins", False)
+        self.faster_joins_enabled: bool = experimental.get("faster_joins", True)
 
         # MSC3720 (Account status endpoint)
         self.msc3720_enabled: bool = experimental.get("msc3720_enabled", False)