Merge commit 'f76194a02' into anoa/dinsic_release_1_21_x

* commit 'f76194a02':
  1.21.0
  Update change log
  1.21.0rc3
  Reduce serialization errors in MultiWriterIdGen (#8456)
  Add Ubuntu 20.10 (Groovy Gorilla) to build scripts. (#8475)
  move #8444 to 'feature'
  linkify changelog

1 files changed, 17 insertions, 0 deletions

diff --git a/synapse/storage/engines/_base.py b/synapse/storage/engines/_base.py

index 908cbc79e3..d6d632dc10 100644
--- a/synapse/storage/engines/_base.py
+++ b/synapse/storage/engines/_base.py
@@ -97,3 +97,20 @@ class BaseDatabaseEngine(Generic[ConnectionType], metaclass=abc.ABCMeta):
         """Gets a string giving the server version. For example: '3.22.0'
         """
         ...
+
+    @abc.abstractmethod
+    def in_transaction(self, conn: Connection) -> bool:
+        """Whether the connection is currently in a transaction.
+        """
+        ...
+
+    @abc.abstractmethod
+    def attempt_to_set_autocommit(self, conn: Connection, autocommit: bool):
+        """Attempt to set the connections autocommit mode.
+
+        When True queries are run outside of transactions.
+
+        Note: This has no effect on SQLite3, so callers still need to
+        commit/rollback the connections.
+        """
+        ...