Stop purging tables which are slated for removal.

changelog.d/16273.misc

@@ -0,0 +1 @@
+Stop purging from tables slated for removal.

synapse/storage/databases/main/purge_events.py

@@ -450,10 +450,6 @@ def _purge_room_txn(self, txn: LoggingTransaction, room_id: str) -> List[int]:
             "e2e_room_keys",
             "event_push_summary",
             "pusher_throttle",
-            "insertion_events",
-            "insertion_event_extremities",
-            "insertion_event_edges",
-            "batch_events",
             "room_account_data",
             "room_tags",
             # "rooms" happens last, to keep the foreign keys in the other tables

synapse/storage/schema/__init__.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-SCHEMA_VERSION = 81  # remember to update the list below when updating
+SCHEMA_VERSION = 82  # remember to update the list below when updating
 """Represents the expectations made by the codebase about the database schema
 
 This should be incremented whenever the codebase changes its requirements on the
@@ -117,6 +117,10 @@
 
 Changes in SCHEMA_VERSION = 81
     - The event_txn_id is no longer written to for new events.
+
+Changes in SCHEMA_VERSION = 82
+    - The insertion_events, insertion_event_extremities, insertion_event_edges, and
+      batch_events tables are no longer purged in preparation for their removal.
 """